Typology of Localities in the Warsaw Metropolitan Area Resulting from the Spatial Development Structure

Abstract

Urban sprawl in Poland has increased due to commune autonomy in spatial planning processes. Local authorities often implement planning measures based on their unit’s interests, overlooking long-term problems such as a lack of schools, kindergartens, commercial infrastructure, and traffic congestion. To address these issues, local governments should consider spatial planning and development projects alongside the development of necessary infrastructure. Many spatial planning methods delimit metropolitan areas based on existing built-up areas and urban corridors located along transport routes. This study analyzed the urban development of the Warsaw Metropolitan Area. Based on a study by the Office of Architecture and Spatial Planning of the Capital City of Warsaw, four urbanization zones of the WMA were delimited, focusing on the accessibility of infrastructure and the urban structure of settlements. At the same time, the population density of each village and each town was calculated, and the area of vacant land was counted. The study found 44 instances of locality types, grouped into four classes, representing peri-urban areas.

1. Introduction

1.1. Legal Basis

Urban sprawl is a phenomenon that has been observed throughout the history of urbanization and is now particularly intense. This process is a natural stage in the development of cities under conditions conducive to their flourishing. Adequate economic and social development attracts new residents and workers. In the past, when, due to overpopulation, settlements crossed the boundaries of cities by expanding outside their walls, the power of cities also extended to suburban areas inhabited by people who were part of the daily functioning of urban society.

Nowadays, when suburban settlements are concentrated in separate territorial units, it is difficult to introduce a mechanism to control such extended urban complexes. During the communist era in Poland, spatial planning was stimulated by a 1946 decree on the planned spatial development of the country [1]. Within the framework of a centrally controlled economy, the authorities imposed on territorial units the direction of their spatial development structure, thus deciding from the top down on the role of a given administrative unit in the plan for building the national economy, as a component of nationwide urban and social structure.

After 1989, following the change of the political system, territorial units were given broader rights in local politics, including in matters related to spatial planning. In the latter, the main regulation was the Spatial Development Act [2], which, however, left a great many doors open for changes made by municipalities. At present, spatial development directions are defined by the Act on the Principles of Development Policy [3], provincial regional development strategies, and regional spatial development plans, as well as local spatial development plans created by municipal authorities. However, the above-mentioned legal documents, as before, provide opportunities for changes in favor of municipalities or local developers. This sometimes leads to only seemingly controlled changes in land use patterns and different expansion policies in urban and suburban municipalities. Broad autonomy of communes in spatial planning processes results in the possibility of uncontrolled growth of urban complexes in directions that may be either more or less beneficial for the environment, the economy, society, or the functioning of cities themselves.

In this article, Polish urban agglomerations are understood as a complex of (urban) settlement units linked by concentrated development and common relations. The above ensembles do not constitute legal territorial units. The units responsible for local spatial planning, i.e., municipalities, are constituent units of counties (powiaty) and voivodeships, which are much larger than urban complexes. Municipalities and counties may join together to form inter-municipal associations and unions, but their participation in any tasks is voluntary. This means that it is not possible to impose or force any decisions or proceedings on the authorities of any of them. Hence, agglomerations bring together units in which suburbanization takes place, continuously expanding areas that have already been urbanized to some extent and merging them together by filling in the communication routes connecting them with development. However, suburban settlements (urban sprawl) are also common, located at a considerable distance from urban centers, even with little demographic significance. These are areas with inadequate infrastructural facilities, where connecting them to local centers generates significant costs and logistical problems. They are advertised by developers and local authorities as being fully functional. In reality, such an example of unwise suburbanization can lead to serious local spatial and socio-economic problems and even paralyze the entire agglomeration.

Another form is metropolitan associations, in which territorial units have been legally allowed to join together since 2015 [4]. So far, one such union has been established—the Upper Silesian–Zagłębian Metropolis, in which the main focus is on the shaping of spatial order, the development of public transport, social and economic development [5].

In the case of the Warsaw agglomeration, the administrative units concentrated in it form the association Metropolia Warszawa. It was created on the basis of a partnership of municipalities and currently covers the units of the NUTS2 sub-region of Warsaw known as the Warsaw Metropolitan Area (WMA), which includes 5 counties and 70 municipalities. The same problems faced by other urban complexes are present here. However, it is the most representative area due to its size and growth rate. Thus, all the problems noticeable in Polish urban complexes accumulate here.

The main legal act affecting the spatial order of the Warsaw metropolitan area is the Spatial Development Plan of the Mazowieckie Voivodeship, but the decisive acts remain the local plans indicating the directions of spatial development in the area. Local spatial development plans (MPZP) are created in compliance with the requirements adopted in the superior acts, but a large proportion of new buildings are constructed in areas not covered by the MPZP on the basis of development conditions issued by the municipal authorities. It should be added that the housing stock resulting from the coverage of the country by local plans in 2011 already exceeded the population of Poland by a factor of two (41 million in single-family housing and 36 million in multifamily housing) [6,7]. This means that issuing additional decisions and planning residential development on more land may, in many cases, be unnecessary.

1.2. Literature Review and Peri-Urban Models

The delimitation of a metropolitan area is guided by a number of factors and variables that link an area together. One criterion is the condition of spatial cohesion to prevent the formation of isolated urban islands. Demographic factors (number of inhabitants, population density, migration dynamics) and urban planning (land use, level of development) are also important [8]. The Warsaw Metropolitan Area includes units with different population densities, migration dynamics, types of land use, and, consequently, occupational structures of their inhabitants. Regardless, the WMA exists, and its boundaries are generally accepted. It can be assumed, therefore, that the above shortcomings are a certain stage in the metropolitan area’s development, which aims to unify demographic, urban, and, above all, spatial cohesion levels. If this is the case, both the city and the suburban areas should have an urban character with extensive infrastructure and technical facilities. At present, the basic act for the preservation of spatial order in the WMA is the Study of the Spatial Development Plan of the Warsaw Metropolitan Area, which includes key development concepts such as the concept of use zones [9].

In theory, the local government’s spatial planning and development projects should be implemented along with the development of the infrastructure needed for this. There are many concepts for creating and supervising spatial order. For example, the theory of the neighborhood unit focusing on the development and maintenance of the urban area level assumes, among other things [10]:

-

adequate accessibility of primary schools (in the original half mile)

-

share of green areas at 10%

-

access to daily life services

-

a unified, harmonious architecture created between the main roads and an extensive system of internal roads

The equivalent in Polish realty was the housing unit, sometimes identified with the housing estate. Although projects based on its functioning were still being realized before World War II, its concretization came during the communist era, when it was defined as “a separate system of residential development with a corresponding program of basic services, leisure and communication facilities distributed within an access distance of up to 500 m” [11]. Although the ordinance introducing it does not have the force of law, many researchers agree that local governments creating local development plans should pay attention to these assumptions, and perhaps they should be imposed in a top-down fashion [12].

Today, C. Moreno’s vision of the 15-min city is gaining popularity. This concept has emerged to meet the growing urban needs of Paris and France as a whole while combating global warming [13]. It assumes an improvement in living standards by creating access to essential services (commerce, healthcare, education, entertainment) and jobs that do not exceed a 15-min commute [14]. It involves the development of public transport in order to almost completely abandon transport by private car. This implies two solutions for the outer areas of the agglomeration: the development of transport to reach facilities easily and quickly or the localization of these goods on site in each urban settlement, the second way being closer to the original assumptions of the 15-min city.

In contemporary urban developments around the world, the Traditional Neighborhood Development (TND) concept based on the neighborhood unit is sometimes used, with the school as the focal point, assuming the development of the unit along traffic routes. TND aims to guarantee an adequate quality of life via access to social services and public transport in areas of new urban developments with appropriately landscaped urban greenery [15]. Important for this study is that the TND concept is usually implemented in areas of expanding suburbs.

The TOD (Transit Oriented Development) unit concept also involves clustering development around public transport hubs [15]. In this case, distinct functional centers are created around stations and stops, where the most relevant services are located. Such a model is largely oriented towards a residential/satellite function, where the resident population uses the aforementioned goods before and after returning from work or school by public transport.

For TND and TOD, the key is to assume an appropriate distance from transport hubs. The original in US conditions is a mile to a train station, half a mile to a tram stop, and a quarter mile to a bus stop [15]. In European conditions, 500, 400, and 300 meters are sometimes adopted, respectively [6,16], but the particular distances depend on the specific characteristics of the country and the degree of development of public transport.

The Urban Boundary Model regional planning method is based on the delimitation of metropolitan areas based on existing railway lines [15]. It provides for the delimitation of urbanization zones with different characteristics based on the extent of development. In addition to urbanized zones, non-urbanized areas divided into four classes are also delimited [6]:

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a rural reserve, available for development in exceptional situations after the use of space in current urbanized zones

-

wastelands located adjacent to urbanized zones, ready for development once the resources in the current urbanized zones are exhausted

-

marginal with only rural development permitted

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excluded, i.e., land that, due to its nature (forests, protected areas), should never be developed

These zones should be adjusted from time to time. It should be noted that the model provides for the delimitation of the above development zones on the basis of the extent of development rather than its intensity (e.g., density of development).

The Rural Boundary Model method, on the other hand, assumes the development of agglomerations within urban corridors based on the course of the railway line. The width of the corridor depends on the possibility of reaching the railway station on foot. Corridors can be connected to each other by smaller corridors, and their intersections occur at key functional nodes. In doing so, the model assumes the exclusion from development of areas distant from the main arteries and the legal protection of the most valuable ones [15].

The peri-urbanization report of Europe conducted for the PLUREL project defines a model of peri-urban and rural–urban areas surrounding a city center [17]. Mono- and poly-centric settlement patterns assume the existence of ring buffers around urban centers, whose population level decreases with distance from the city.

With these concepts and planning methods in mind, a model was developed for the Warsaw Metropolitan Area (Figure 1). According to these assumptions, the WMA should have the form of a ring with adjacent suburbs, developed most where there are railway stations and developed least in places without access to rail transport. From the center, urbanized corridors along the seven existing railway lines should diverge radially. The eighth, less-developed corridor (northwestern) may be a sequence of developments along the DK7 route (Warsaw – Zakroczym) through Łomianki, which, in the absence of a railway line with developed public transport, may play the role of an axis. The strategic sections of the corridors should include nodes from which the primary corridors are connected via second-level routes. The level of urbanization of the corridors should decrease with the distance from the central center, and their peripheries should provide facilities for expansion in the event of depletion of the corridor resources.

New urban settlements should be developed in locations with adequate infrastructure and accessibility, provided that the sites do not disturb existing exclusion zones (e.g., nature conservation areas). Such settlements should have adequate access to basic services, including a primary school, and there should be well-developed public transport in the form of rail or bus transport.

It is well known that in such a large and diverse entity as the WMA, which is also still in the process of being created, it is impossible for all urban settlements, let alone suburban ones, to meet the standards resulting from the assumptions described above. In addition, due to the different policies of the municipalities that make up the WMA, the lack of real cooperation within the metropolis, and the lack of binding top-down guidelines, some areas develop better and some less well. It is therefore crucial to maintain access to the basic amenities associated with adequate development and to closely monitor them to ensure that these amenities are maintained. As a first step, it seems natural to examine the current state of development in the various WMA areas, paying attention to the degree of development of the urban fabric and the availability of services.

Such a study was undertaken by the Office of Architecture and Spatial Planning of the Capital City of Warsaw, which carried out an analysis of the degree of development of the urban fabric of urbanized areas. The study took into account the area, intensity, and impermeability of development and the density of streets (including paved roads), as well as the availability of educational services, public transport, and utilities [18]. In this way, information on the saturation of land with buildings was obtained, and places where there is a need to develop the urban structure and related areas ready for investment were identified. However, the study was conducted only within the administrative boundaries of the city of Warsaw and not in other areas of the metropolitan area.

For the purposes of the Study of the Spatial Development Plan for the Warsaw Metropolitan Area, the entire metropolitan area was dealt with by delimiting four urbanization zones of the Warsaw Metropolitan Area: completion, development, and preservation of development, as well as a zone excluded from development. The study defined the main directions of spatial development, including the stages of development and functionality of the settlement network (urban and suburban areas of Warsaw) [9]. The study is, however, a prelude to the establishment of the WMA Development Plan, and the delineated zones have a regional rather than a local dimension.

The delimitation of metropolitan areas and agglomerations in Poland is carried out by taking municipalities or counties as the basic unit. Whole regions are then surveyed in these units. This is facilitated by the availability of data, which is usually provided for territorial units or their urban and rural parts.

For example, Majewska examines the dynamics of suburbanization processes analyzing in WMA cities [19]. Degórska analyzes ecological and landscape changes in rural areas, focusing on units in the form of rural municipalities and rural parts of urban–rural municipalities [20]. Population changes in metropolitan areas are also studied in municipalities [21]. Also, Degórska created a typology of municipalities based on the development of buildings, designating five types of municipalities: those with significant, moderate, little, and no growth and non-urbanized areas [22]. In another study, she classified the municipalities of the WMA using cluster analysis to determine their nature of development [23].

Another approach is to use raster land cover layers for land use studies. Grochowski et al. thus study WMA development scenarios based on Urban Atlas data [24]. Werner et al., on the other hand, studied land use change based on population potential, relying on Corine Land Cover data, but visualized the results for municipalities for clarity [25]. A significant item is the theoretical and practical framework for the study of urban growth and urban sprawl using remote sensing data presented by Batta [26].

There are places in Poland that are not cities, but their character is typically urban. In metropolitan areas, their occurrence is common. They are an integral part of rural territorial units, despite the frequent lack or minimal presence of agrarian resources. For a variety of reasons, political and economic, they are not part of cities or separate urban centers and are coutned as villages in statistics. The most densely populated village in Poland has over 12,000 inhabitants and is more populous than many towns. The most densely populated village, on the other hand, is also located in the vicinity of Warsaw. It is therefore necessary to take a closer look at the development of the individual villages, not the municipalities or cities themselves.

1.3. Research Goals

The Polish urban space has been facing the problem of migration for years, because the major urban agglomerations have for several decades been experiencing a continuous influx of people from rural and inner-city areas linked to the desire for better living conditions. The initial migration wave originated in rural areas and medium-sized cities. This was linked to the move away from a centrally controlled economy and the associated closure of large state-owned companies in medium-sized cities and agricultural cooperatives in rural areas.

At present, the trend is for residents to flee overcrowded city centers and move within an agglomeration, often without changing their current place of employment. The form of deciding to relocate is often no longer job-seeking factors. Financial factors are still decisive but are often related to cheaper land, cheaper living, or lower commuting fees. Although there is still an influx of people from less-developed areas into Polish cities and their surroundings, much of the change is taking place within settlement systems. In the WMA, due to the volume of the metropolitan area and the well-developed transport network, residents are able to choose where they live without having to change jobs. Their preferences—neighborhood, transport, accompanying services—therefore play a decisive role. The influx of people from outside into the cities of the WMA has led to an increase in population density, which in turn has triggered processes of migration of residents to less populated areas. Suburban areas are thus growing largely due to the migration of urban populations fearing urban overcrowding.

In the absence of top-down imposed guidelines, the implementation of planning measures is left to the local authorities, which, however, perform this task in a way that is most beneficial for their unit rather than the common benefit of the entire metropolitan area. Local authorities see interest in the increasing influx of people from both peripheral and inner-city areas. Suburban municipalities attract residents, as this provides more revenue for the budget and thus opportunities for the development of the entire municipality. Units, as well as developers, attract residents by competing with each other [6], by offering attractive qualities to potential buyers (e.g., large plots of land, peace and quiet, low price), while ignoring long-term problems (lack of schools, kindergartens, commercial infrastructure, generation of traffic jams by commuting from places far away from the cities).

Planning at the metropolitan level is intended to combat this type of practice in order to preserve harmony in the functioning of urban centers and their hinterlands. Appropriate legislation could easily control the mechanisms of sprawl resulting from high migration. The absence of such guidelines leads to chaos in both the local and regional spheres. For the local population, it can result in a lack of frontline services and the social exclusion of facilities beyond the capacity of local authorities to act. For the latter, it creates the problem of costly investment in areas away from the center of the municipality. At the regional level, the lack of regional planning activities can lead to the paralysis of an entire agglomeration. The problem includes transport routes. The higher population of suburban areas affects the capacity of the roads used by suburban residents to commute to work. It also affects the efficiency of public transport, its punctuality, and its comfort.

Such situations are the result of the uneven distribution of settlements and overcrowding, which affect both urban and rural areas. Each unit (be it a town, a village, or a whole region) has its own absorption capacity and development potential. It is therefore important to identify where these opportunities have been exhausted and where there is potential for further development.

The methods of research into metropolitan problems mentioned in subchapter 1.2 usually use the municipality as the basic unit, i.e., the basic administrative unit of Poland. This is justified, as statistical data in the most accurate form is presented precisely for municipalities. The problem begins where there is a need for a more detailed analysis and a deeper understanding of individual units.

This study undertook an examination of the current state of WMA localities in terms of urban development using its own methods and those described above. Via a thorough analysis of all the localities in the WMA, the degree of development of the urban fabric and the availability of services were measured. Another aim of the study was to create a typology of units in terms of their current character and development opportunities and to assess the correct development of the WMA in the directions assumed in the presented model.

2. Materials and Methods

The main database constituting the vector base was the Database of Topographic Objects (Baza Danych Obiektów Topograficznych—BDOT10k) made available by the Central Statistical Office, which is a complete database of land cover in Poland [27]. Ad hoc use was made of other databases and compilations introduced due to the insufficiency or incompleteness of BDOT10k.

On the basis of the BDOT10k database (ADMS layer), all localities (towns and villages) located in the WMA except Warsaw were selected for the study. Due to the proximity of the WMA and the participation of the city of Żyrardów in the partnership programs of the Association “Metropolia Warszawa” (including the EU program of Integrated Territorial Investments), the localities of Żyrardów County were also taken into account. In the further part of the study, all selected localities were analyzed in terms of urban planning and infrastructure (level of development and availability of infrastructure), demographics (population density) and use (land available for development). The localities were then combined into so-called statistical localities, which are discussed in more detail further on.

The urban–infrastructural part was carried out using built-up areas (PTZB BDOT10k layer), in which the level of development (density of buildings and number of building stories) and the availability of infrastructure (rail and road transport and public services) were checked (

Table 1. Urban and infrastructure indicators.

Sym.	Share	Indicator	Method of Calculation	Stage
Bd	25%	Building density	distance of the building from 4 neighboring buildings - average in built-up area	Urbanization Level
As	20%	Average building height	number of building stories - average in built-up area
Rd	10%	Density of paved roads	length of any paved roads in km per built-up area in km2
Rpd	10%	Density of roads	length of roads in km per built-up area in km2
Arl	15%	Rail transport	travel time from railway stations on foot and by car - average in built-up areas	Availability of Infrastructure
Ard	10%	Public transport by road	travel time from bus stops on foot and by car - average in built-up areas
Ap	10%	Access to public services	Length of distance to primary school, pharmacies, clinics on foot and by car - average in built-up areas

). The selection of parameters was modelled on the work of the Office of Architecture and Spatial Planning of the Capital City of Warsaw regarding the designation of areas with a developed urban structure [9].

Building density (Bd) was calculated by measuring the distances (l) of each building (b) from the BUBD layer (BDOT10k) from 4 neighboring buildings in a straight line and calculating the average distance value for the built-up area in which the buildings are located (Formula (1)). Distances were measured from the centroids of each building.

$$\mathrm{Bd}=\frac{\left({\mathrm{l}}_{\mathrm{b}1-\mathrm{b}2}+{\mathrm{l}}_{\mathrm{b}1-\mathrm{b}3 }+{\mathrm{l}}_{\mathrm{b}1-\mathrm{b}4}+{\mathrm{l}}_{\mathrm{b}1-\mathrm{b}5}\right)+\left({\mathrm{l}}_{\mathrm{b}2-\mathrm{b}1}+{\mathrm{l}}_{\mathrm{b}2-\mathrm{b}3}+{\mathrm{l}}_{\mathrm{b}2-\mathrm{b}4}+{\mathrm{l}}_{\mathrm{b}2-\mathrm{b}5}\right)+\left({\mathrm{l}}_{\mathrm{bn}-\mathrm{b}1}+{\mathrm{l}}_{\mathrm{bn}-\mathrm{b}2}+{\mathrm{l}}_{\mathrm{bn}-\mathrm{b}3}+{\mathrm{l}}_{\mathrm{bn}-\mathrm{b}4}\right)}{4{\mathrm{n}}_{\mathrm{b}}}$$

(1)

The average number of stories (As) of the buildings in a given built-up area was calculated from the building layer attribute table (BUBD), where the LKOND column reports the number of stories (s) in a given building (Formula (2)).

$$\mathrm{As}=\frac{{\mathrm{s}}_{\mathrm{b}1}+{\mathrm{s}}_{\mathrm{b}2}+{\mathrm{s}}_{\mathrm{bn}}}{{\mathrm{n}}_{\mathrm{b}}}$$

(2)

From the SKDR road layer (BDOT10k), the length of roads (Rd) in each built-up area was calculated by dividing the length (l) of roads (r) crossing the built-up area in kilometers by its area in square kilometers (a). The survey was repeated after road selection—rejecting unpaved roads (column MATNAWIERZ in the SKDR BDOT10k layer table). This yielded information on the density of roads and the density of paved roads in each built-up area (Formula (3)).

$$\mathrm{Rd}\left(\mathrm{Rpd}\right)=\frac{{\mathrm{l}}_{\mathrm{r}1}+{\mathrm{l}}_{\mathrm{r}2}+{\mathrm{l}}_{\mathrm{rn}}}{\mathrm{a}}$$

(3)

Each task was scored separately and performance was assessed on a three-level scale (high, medium, low intensity). Due to the level of significance, the individual tasks were given different scoring scales. The density of buildings received a maximum of 25 points, the average number of stories was 20 points, and the density of paved roads and all roads was 10 points each (

Table 2. Classification by intensity and scoring of individual urban tasks.

Task	Large (pts)	Medium (pts)	Small (pts)	Units
Bd—Building density	<50 (25)	≥50–<100 (12.5)	≥100 (0)	m.
As—Avg. number of stories	≥2.5 (20)	≥1.5–<2.5 (10)	<1.5 (0)	stories
Rpd—Road density (paved)	≥10 (10)	≥1–<10 (5)	≥10 (0)	km./km2
Rd—Road density	≥10 (10)	≥1–<10 (5)	≥10 (0)	km./km2

Note: All tasks were performed in QGIS 3.30 software.

).

The accessibility part of the infrastructure consisted of three tasks: accessibility of collective rail transport, collective wheeled transport, and public services. The study consisted of network analyses through which accessibility zones (Service Areas) were created for the key facilities selected for the study.

Rail accessibility was measured in terms of the time taken to reach a railway station on foot (30 min) and by car (15 min). The study was conducted for the entire study area, including the Warsaw area, due to the location of Warsaw’s railway stations near the city limits, which affects rail accessibility among areas adjacent to Warsaw (e.g., PKP Warszawa Gołąbki, PKP Warszawa Dawidy).

Due to the obsolescence of bus stops contained in the BDOT10k database, objects from the Open Street Map database [28] were selected for the study of circular transport. On the basis of existing timetables, diagrams, maps and mobile applications, bus stops from the OSM database were verified and corrections were made to their location and activity. For the identified stops, accessibility zones were created and measured—with access times of 5, 10 and 15 min—for each carrier separately. All zones were superimposed and, using map algebra, combined to create three non-intersecting zones: 0–5 min, 5–10 min, 10–15 min.

The third task was the accessibility of public services, measured by the length of the walking route (1 km) and the car route (3 km). This accessibility was checked for public primary schools, pharmacies, and primary health care clinics. The source for the identification of schools was the KUOS vector layer from BDOT10k verified against the list of schools from the Register of Schools and Educational Institutions [29]. The address database of currently operating pharmacies and outpatient clinics was retrieved from the eHealth Centre’s Medical Registers [30]. These addresses were then geocoded in Google Earth Pro (Register of Pharmacies) and ArcGIS Pro (Register of Medical Entities).

The built-up areas were assigned, on the basis of accessibility, a corresponding score for the coverage of the individual zones (

Table 3. Classification by accessibility zone and scoring of individual urban tasks.

Accessibility	Pedestrial (pts)			Car (pts)	Units
Arl—Rail transport	≤30 (7.5)			≤15 (7.5)	min.
Ard—Road transport	0–5 (10)	5–10 (7)	10–15 (4)	-	min.
Ap—Public services (including):	(5)			(5)
Aps—Primary schools	≤1 (2)			≤3 (2)	km.
Aph—Pharmacies	≤1 (1.5)			≤3 (1.5)	km.
Primary care clinics	≤1 (1.5)			≤3 (1.5)	km.

Note: Network analyses were performed entirely in ArcGIS Pro using Network Analysis (Service Area) tools with appropriate parameters for pedestrian and vehicular zones.

) similarly to the urban development section.

The results of the two stages were then combined to produce a total score for the built-up areas (maximum 100 points). In this way, the degree of development of the urban (urban) fabric was obtained. The results obtained were divided into three classes of built-up areas: developed (Class I—more than 75 points), developing (Class II—50–75 points) and undeveloped (Class III—less than 50 points).

The data on built-up areas prepared in this way is used to examine the urban structure of the settlements in which they are located. On this basis, the percentage share of developed areas in the locality was calculated. Again, a classification was used, this time to distinguish between types of localities, taking the urbanization level of Polish metropolises—specifically voivodeship cities—as the basis for the division.

In 2014, the size of urbanized land in each of the provincial cities exceeded 30% of the total area. Only in two cases (Białystok and Warsaw) was it above 50%. We are talking about all urbanized land and therefore also land that is not actually built up. When we look at the built-up areas, we find that the percentage drops to a maximum of 32% in Białystok and 34% in Warsaw. Nowhere, however, was it lower than 15% [31]. It should be noted that the built-up land in the provincial cities is mostly heavily urbanized and therefore theoretically has at least a moderately developed urban fabric.

With reference to the above, a five-level scale was formulated for the classification of settlements (S0–S4). The S4 group of settlements included those with a developed urban fabric covering more than 50% of the land. Settlements with an area of 30-50% covered by such areas were classified as S3. Group S2, on the other hand, is made up of units covered by Class I built-up areas at a level of 15–30%. Villages that have at least 15% of their area covered by built-up areas of at least Class II and that do not fall into the previous three groups were characterized as S1. The remaining units were classified as S0 (

Table 4. Development level of the urban structure.

S	Urban Structure	Level
4	above 50% KI	fully developed
3	30–50% KI	developed
2	15–30% KI	moderately developed
1	above 15% KI + KII	evolving
0	other units	undeveloped

).

Data from the most recent national census conducted in 2021 [32] were used to examine the population density of individual localities. Data were collected for all localities in Poland, but, due to statistical secrecy, were published for so-called statistical localities. Such units mainly correspond to towns and villages, but in special cases, villages have been combined into larger units. This is the case when the value of some characteristic obtained in the census is small enough to identify the people who possess it. However, this is a problem for small villages, and the change does not significantly affect the results. Nevertheless, despite the few cases, it was decided to use a list of statistical localities for further research. A full list of these can be found on the website for Statistics Poland [33].

The area of the units in question was calculated based on their vector visualization in the Topographic Objects Database (ADMS layer) after the objects had been combined into statistical localities.

The population density results obtained allowed for the division of settlements into five classes (G0–G4), where G0 is the least and G4 is the most populated group of settlements. The most densely populated group of settlements (G4) is that where the population density exceeds 2000 people per km². Such population density is found in the most heavily urbanized cities in Poland, including seven provincial seats [34]. A densely populated group of localities is also G3, which includes localities with a population density of 1000–2000 people per km², which is still a high value under Polish conditions (nine voivodeship cities). Units with a density of 500–1000 persons per km² were classified as moderately populated (G2) due to the fact that the median population density in cities in Poland is slightly less than 500 persons/km². Towns with fewer than 500 and more than 100 inhabitants/km² were considered sparsely populated (G1). The most sparsely populated group (G0) consists of units with fewer than 100 inhabitants per square kilometer (

Table 5. Population density level.

G	Population Density	Level
4	more than 2000 p./km2	very densely populated
3	1000–2000 p./km2	densely populated
2	500–1000 p./km2	moderately populated
1	100–500 p./km2	sparsely populated
0	0–100 p./km2	very sparsely populated

).

The study of the development of the settlements was based on the almost complete BDOT10k database. Its surface objects were used to investigate the area of built-up areas in the given localities. Objects were divided into three types—vacant, occupied, and excluded areas (

Table 6. Land cover objects selected for survey (source: BDOT10k).

Code	Name of Object Class	Attribute	Name of Facility	Status
LAND COVER (PT)
PTWP	surface water	PTWP01	seawater	excluded
		PTWP02	flowing water	excluded
		PTWP03	standing water	excluded
PTZB	built-up	PTZB01	multi-family housing	occupied
		PTZB02	single-family housing	occupied
		PTZB03	industrial and warehouse built-up areas	occupied
		PTZB04	commercial and service built-up areas	occupied
		PTZB05	other built-up areas	occupied
PTLZ	forest and wooded area	PTLZ01	forest	excluded
		PTLZ02	grove	vacant
		PTLZ03	woodland	vacant
PTRK	shrub vegetation	PTRK01	mountain pine	vacant
		PTRK02	shrubs	vacant
PTUT	permanent crop	PTUT01	allotment	excluded
		PTUT02	plantation	excluded
		PTUT03	orchard	excluded
		PTUT04	forest nursery	excluded
		PTUT05	ornamental plant nursery	excluded
PTTR	grassland vegetation and agricultural crops	PTTR01	grassy vegetation	vacant
		PTTR02	arable land cultivation	vacant
PTKM	land under roads, railways and airports	PTKM01	land under a circular road	occupied
		PTKM02	land under the track	occupied
		PTKM03	land under the vehicular road and track	occupied
		PTKM04	land under the airport road	occupied
PTGN	unused land	PTGN01	scree, spoil, or rock rubble	vacant
		PTGN02	rocky terrain	vacant
		PTGN03	sandy or gravelly terrain	vacant
		PTGN04	remaining unused land	vacant
PTPL	square	PTPL01	square	occupied
PTSO	landfill	PTSO01	municipal waste storage area	vacant
		PTSO02	industrial waste storage area	vacant
PTWZ	excavation and heap	PTWZ01	excavation	vacant
		PTWZ02	heap	vacant
PTNZ	other undeveloped land	PTNZ01	land under technical facilities or structures	vacant
		PTNZ02	industrial and storage area	vacant
PROTECTED AREAS (TC)
TCON	Natura 2000 area	TCON01	Natura 2000 area	excluded
TCPK	landscape park	TCPK01	landscape park	excluded
TCPN	national park	TCPN01	national park	excluded
TCRZ	reserve	TCRZ01	reserve	excluded
LAND USE COMPLEXES (KU)
KUOZ	health and social care complex	KUOZ01	social welfare institution or children’s home	occupied
		KUOZ02	hospital or sanatorium complex	occupied
KUHO	complex hotel services	KUHO01	hotel or motel	occupied
		KUHO02	campsite	occupied
		KUHO03	leisure center	occupied
		KUHO04	tourist hostel	occupied
KUPG	industrial and economic complex	KUPG01	CHP plant	occupied
		KUPG02	power plant	occupied
		KUPG03	gasworks	occupied
		KUPG04	livestock farm	occupied
		KUPG05	steelworks	occupied
		KUPG06	mine	occupied
		KUPG07	sewage treatment plant	occupied
		KUPG08	electricity substation	occupied
		KUPG09	pumping station	occupied
		KUPG10	refinery	occupied
		KUPG11	landfill	vacant
		KUPG12	water intake area	occupied
		KUPG13	metallurgical plant	occupied
		KUPG14	production, service, or repair facility	occupied
		KUPG15	recycling plant	occupied
		KUPG16	water supply company	occupied
KUHU	retail and service complex	KUHU01	shopping and service center	occupied
		KUHU02	marketplace or bazaar	occupied
KUKO	communication complex	KUKO01	bus station	occupied
		KUKO02	aerodrome or airstrip	occupied
		KUKO03	place of traveler services	occupied
		KUKO04	car park	occupied
		KUKO05	water port or harbor	occupied
		KUKO06	railway station	occupied
		KUKO07	metro station	occupied
		KUKO08	filling station	occupied
		KUKO09	railway area	occupied
		KUKO10	transport depot or base	occupied
KUSK	sports and leisure complex	KUSK01	botanical garden	occupied
		KUSK02	zoo	occupied
		KUSK03	sports and leisure center	occupied
		KUSK04	park	occupied
		KUSK05	complex of holiday homes	occupied
KUOS	educational complex	KUOS01	research center	occupied
		KUOS02	nursery or creche	occupied
		KUOS03	school	occupied
		KUOS04	college	occupied
KUZA	historic complex	KUZA01	place of national remembrance	occupied
		KUZA02	open-air museum	occupied
		KUZA03	fortress	occupied
		KUZA04	museum complex	occupied
		KUZA05	palace complex	occupied
		KUZA06	castle complex	occupied
KUSC	acred complex and cemetery	KUSC01	cemetery	occupied
		KUSC02	religious or monastic complex	occupied
KUIK	other land use complex	KUIK01	military training ground	occupied
		KUIK02	special plant	occupied

). The latter included areas excluded from development for natural and cultural reasons. These are mainly protected areas, water areas, large concentrations of forest, permanent crops such as orchards, and forest nurseries or national heritage areas. The group of occupied areas includes areas that are already built up, irrespective of the level of development, as well as other urbanized areas such as roads, service, and recreational or transport complexes. Vacant areas, on the other hand, are areas that are theoretically suitable for development as they are not included in any of the previous classes. These are mainly unused grassy, shrubby, or lightly wooded undeveloped areas, as well as areas of seasonal crops.

In terms of the area of vacant land, the settlements were divided into 5 groups (Z0–Z4). Group Z4, with potentially the greatest spatial possibilities, comprises localities with more than 5 km² of undeveloped but theoretically developable areas. Slightly less space, 2.5–5 km² is found in the villages in group Z3. This is assumed to be in the medium range. More than 1 km² and less than 2.5 km² of open space characterize units in group Z2. Such units were categorized as having low expansion potential. Areas of less than 1 km² of free space were considered to be practically utilized space. They are possessed by units classified in group Z1. Z0, on the other hand, is a group of localities where further development is impossible or inadvisable due to high urbanization or the location of areas excluded from development (

Table 7. Percentage of land free of development.

Z	Vacant Lots	Possibility
4	over 5 km2	large
3	2.5–5 km2	average
2	1–2.5 km2	small
1	0–1 km2	fully utilized
0	0 km2	prohibited

).

In the next step, the results of the settlements for all groups—urban–infrastructural (S), population density (G), and development (Z)—were collated. In this way, 44 instances of locality types were obtained, which were then combined by similarity and degree of urbanization into XIII classes representing the potential direction of spatial development (

Table 8. Types of locality.

Intensive Urbanization Zone—Housing Completion Zone
I		II		III
S4G3Z1	Fully developed structure, high population density, little opportunity for further expansion	S3G3Z1	Developed structure, high population density, little opportunity for further expansion	S3G3Z3	Developed structure, high population density, medium potential for further expansion
S4G4Z1		S3G3Z2		S3G4Z3
S4G4Z2		S3G4Z1		S3G4Z4
		S3G4Z2
Urbanization Development Zone—housing expansion zone
IV		V
S2G2Z3	Moderately developed structure with medium population, medium potential for further expansion	S2G1Z1	Moderately developed structure with relatively low population density with little room for expansion
S2G3Z3		S2G1Z2
S2G3Z4		S2G1Z3
		S2G2Z1
		S2G2Z2
		S2G3Z1
Adaptation Zone—zone for the preservation and possible development of buildings
VI		VII		VIII
S1G1Z4	Developing development with high density, plenty of room for expansion	S1G1Z1	Developing development, density and vacant land dependent on size of village	S1G0Z1	Development expanding despite low density with no room for further expansion
S1G2Z3		S1G1Z2		S1G0Z2
S1G2Z4		S1G1Z3
S1G3Z4		S1G2Z1
		S1G2Z2
		S1G3Z1
Open Zone—zone intended for development only after use of adjacent resources
IX		X
S0G0Z3	Undeveloped or insignificant development in relation to the area of the village, a potential low-density urban backdrop with high capacity	S0G0Z1	Undeveloped, low-density, small-scale urban development
S0G0Z4		S0G0Z2
S0G1Z3		S0G1Z1
S0G1Z4		S0G1Z2
		S0G2Z3
Closed Zone—exclusion zone
XI		XII		XIII
S0G0Z3	Undeveloped or insignificant development in relation to the area of the village, agricultural or agro-forestry land, remote from developed areas	S0G0Z1	Undeveloped or insignificant development in relation to the area of the village, mainly woodland, away from developed areas	S0G0Z0	forest areas and protected areas, completely excluded
S0G0Z4		S0G0Z2
S0G1Z3		S0G1Z1
S0G1Z4		S0G1Z2
S0G2Z2

).

3. Results

3.1. Urban Structure and Existing Infrastructure

As a reminder, in order to study the urban structure of WMA localities, the density of buildings, the average number of stories, the density of roads, and the availability of public services in built-up areas were counted.

The average number of stories exceeds 2.5 stories only in urban areas and in the few settlements located near them. The density of roads is higher the closer one is to transport hubs. Thus, areas located near Warsaw have the highest ratio of both paved roads and all roads. Nodes in other cities also have an extensive road network. On the other hand, the highest density of buildings can be observed along major transport routes, mainly railways. The areas outside Warsaw are also characterized by dense buildings.

The availability of services and public transport depends largely on the size of urban centers. Even if railway stations are located in small towns, bus transport in these places is provided on a much smaller scale than in cities, or sometimes not at all. It is natural that where rail does not occur, the role of the main mode of public transport is taken over by the bus. The closer to the cities, however, the more developed the transport infrastructure is, as can be seen both in the vicinity of Warsaw and in the other urban centers. Theoretically rural areas located near Warsaw are also characterized by good accessibility to services (primary schools, pharmacies, clinics). Rural areas distant from the capital sometimes have easy access to schools, which are often located in villages, but health care centers are most often located in the city or in a remote village.

Taken as a whole, the highest values of the comprehensive urban-transport index are found in the cities and areas adjacent to Warsaw (more than 75 points out of a possible 100). Certain clusters of areas with such high indicators are observed southwest of Warsaw and along transport routes (Figure 2). The lowest scores (below 50 points) are observed mainly in areas without communication routes at a great distance from Warsaw and other urban centers. There are exceptions, however, as such areas also occur near cities, including Warsaw itself.

The above results translate into indicators for the localities themselves. Almost all localities classified as S4 (urban structure fully developed) are suburban localities bordering Warsaw or remaining in its immediate vicinity (Figure 3). These are two towns (Piaseczno, Piastów) and five villages (Kwirynów, Blizne Jasińskiego, Nowe Grocholice, Rybie, Nowa Iwiczna, Józefosław). The whole is completed by the village of Lipinki, located in the northeastern part of the agglomeration. Classes S3 and S2 (well- and moderately well-developed structures) comprise almost all towns of the WMA and strongly developed rural municipal centers. These classes also include localities adjacent to Warsaw (villages located on the western side) and other cities. Class S1, i.e., the group of settlements with developing buildings, is characteristic of rural areas dispersed throughout the metropolitan area. Its main concentrations, however, are close to the cities, primarily in the western part of the agglomeration. This class also includes a few sprawling towns that, due to their size and/or distance from Warsaw, have not yet been sufficiently developed. These include Nowy Dwór Mazowiecki, Nasielsk, Radzymin, and Góra Kalwaria.

The remaining localities, i.e., those classified as S0, do not have an urban–infrastructural structure developed to an appropriate level on a village-wide scale. However, this does not mean that this structure does not exist there. In many cases, built-up areas, although strongly developed, constitute only a small part of the unit due to the protected and forested areas located there. This is the case for, among others, Karczew and Zielonka, two extensive forested towns.

The whole gives the impression of continuity between Warsaw and the surrounding, although not completely, urbanized localities. Also visible are urban tracts radiating away from Warsaw, especially towards the southwest (Piastów—Grodzisk Maz.), northeast (Ząbki—Duczki), and south (Józefosław—Zalesie Górne). Urban islands of clusters of towns and cities (e.g., Mińsk Mazowiecki, Legionowo, Żyrardów) or solitary units (e.g., Tłuszcz, Błonie, Mrozy) are also visible, more or less distant from Warsaw.

3.2. Population Density

The Warsaw Metropolitan Area is a very heavily populated area in relation to Poland as a whole. The average population density of the country is 121 persons per km² [35], and here it is a value far below the average. The most densely populated cities in Poland are located here (Piastów—4054 p./km², Ząbki—3998 p./km², Legionowo—3950 p./km²), as is the most densely populated village itself (Józefosław—4262 p./km²). The growth of the agglomeration has allowed it to overtake Silesian cities, which not so long ago led the way in terms of population density in Poland, in this comparison.

Class G4, i.e., the most densely populated, also includes highly urbanized towns (Łomianki, Ząbki) and villages tangential to Warsaw (Raszyn, Rybie, Mysiadło), as well as the majority of county towns (Pruszków, Grodzisk Mazowiecki, Żyrardów, Piaseczno, Mińsk Mazowiecki, Wołomin). In all of them, the population density exceeds 2000 persons/km² (Figure 4). The group of densely populated settlements (G3) includes mainly cities. They are mostly municipal towns, but there is also one county seat (Nowy Dwór Mazowiecki). In these units, the population density varies between 1000 and 2000 persons/km². The whole is complemented by small villages with relatively high dispersion. Class G2, i.e., moderately densely populated settlements, is largely represented by villages neighboring towns. However, there are also urban (Nasielsk, Konstancin-Jeziorna, Józefów, Góra Kalwaria, Radzymin) and rural municipal centers, and even one county town (Otwock). The population density in this group does not exceed 1000 persons/km² but is higher than 500 persons/km². However, a significant number of the settlements surrounding Warsaw are relatively sparsely populated (G1), which means that fewer than 500 people/km² and more than 100 people/km² live there. Such settlements also surround other cities in the region and are smaller or larger urban clusters in rural areas, often the most populated part of a rural municipality. This group also includes the towns of Zielonka and Karczew, where the population density is offset by the area of forest located within the unit. The villages in class S1 are relatively sparsely populated, looking at the whole WMA. However, on a national scale, this class can be considered densely populated. The least populous class is the one with fewer than 100 inhabitants per km². It contains mainly peripheral villages, considerably distant from Warsaw. These are villages located in agricultural or forested areas. There are also single units located on the border with Warsaw or in its close vicinity. In most cases, the category of the latter localities is due to the presence of protected areas located within the boundaries of the units.

As in the case of the urban structure study, a ring of towns surrounding Warsaw, this time densely populated, is visible. Even more visible are the radial corridors of heavily populated localities diverging from Warsaw. In this case, the northern direction (Jabłonna—Legionowo—Borowa Góra) or the eastern direction (Sulejówek—Mińsk Mazowiecki) are more visible. However, the most visible directions are southwest (Piastów—Grodzisk Mazowiecki—Żyrardów), northeast (Ząbki—Wołomin—Tłuszcz), and south (Józefosław—Piaseczno—Gabryelin). In addition, some centers form islands of densely populated towns (e.g., Błonie, Nasielsk).

3.3. Landscaping

The Warsaw Metropolitan Area is an extremely diverse region in terms of land use. Despite its highly urbanized character, a large area is occupied by agricultural or post-agricultural land and more or less extensive forest areas.

There are many protected areas here, the most important of which is Kampinos National Park. In addition to it, there are landscape parks in the WMA—Mazowiecki and Chojnowski, as well as part of the Nadbużański and Bolimowski (outside the WMA, in the surveyed area of the Żyrardów district). In addition, the Vistula valley occupies a large part of the area, sometimes covering more than half of the town. As a watercourse itself, it is excluded from development, while at the same time, its riverbed and, in many places, its banks are protected. Other forms of protection present in the WMA include minor nature reserves, ecological grounds, or natural landscape complexes, as well as the more extensive Natura 2000 areas. A large part of the area is also made up of protected landscape areas. In the latter, however, mass construction is allowed.

Agricultural land can be divided into two groups. The first consists of areas where single-season farming or animal husbandry is or used to be in operation, as are meadows and pastures. These are areas where development is possible due to the relatively easy process of land parcel disaggregation. The second category is permanent crops, i.e., land where cultivation is perennial, such as orchards. These tend to be large areas that occur virtually only in the southern part of the WMA. Changes in these places can therefore be more complex, and this area should be recognized as occupied land.

The urbanized areas within the boundaries of the WMA cover an increasing area every year. In the past, larger clusters of buildings were concentrated only along transport routes (originally roads, then railways). Nowadays, development is increasingly dispersed (Figure 5). However, the best visible sequence of buildings is still along the Warsaw –Vienna railway line, stretching from Warsaw through Pruszków, Grodzisk Mazowiecki, and Żyrardów. Large clusters of occupied areas also occur on the outskirts of Warsaw—in the southern part (Piaseczno—Konstancin–Jeziorna), the southeast (Józefów—Otwock), or the northeast (Ząbki, Marki, Zielonka, Kobyłka, Wołomin).

However, the presence of built-up clusters does not always translate into the degree of urbanization of a locality, as shown by the results of step 3.1. The same is true for the analysis of vacant land (Figure 6). Large units, including towns (Z3 and Z4), have the greatest potential for expansion. Despite the strong buildup in most cities, there is still plenty of room for further urban expansion. Rural units with a large area are often the ones with the greatest urbanization potential (Z4). Slightly smaller units have this possibility at a medium level (Z3). Villages of both classes are most numerous in the western and northern parts of the WMA and in slightly smaller numbers in the eastern part, where they predominate mainly on the edge of the agglomeration and the entire province. The southern part of the WMA has the smallest number of them. There, they are dominated by localities with little (Z2) or negligible (Z1) potential for expansion. Units classified in this way can be observed throughout the metropolitan area, regardless of the size of the unit. Larger clusters are found along transport routes. Cities of this type include Łomianki, Piastów, Józefów, or Ząbki adjacent to Warsaw, as well as Piaseczno, Legionowo and Radzymin, which are more or less distant. In the WMA area, there are also large islands of areas where development is forbidden (Z0) or urban possibilities are negligible (Z1). These are associated with the aforementioned forms of nature conservation. The largest such area is the Kampinos National Park area, located in the western part of the WMA. The area of Mazowiecki Landscape Park is also visible, namely its southern part, located southeast of Warsaw.

3.4. Typology of Settlements

On the basis of the juxtaposition of the previously calculated S, G, and Z indices, XIII development classes were delineated (Table 8), grouped on the basis of the use zones of the Warsaw Metropolitan Area Land Use Plan Study [6]. The effect of the typology is shown in Figure 7.

The first three classes (I–III) representing the most intensive development are mainly very densely populated and built-up cities, as well as suburban villages with the same structure. The most overburdened are the settlements surrounding Warsaw from the southwestern side (Class I). In this class, large urban developments that do not require changes to the current built-up area are impossible. Only the replenishment of the urban fabric and the reorganization of already urbanized areas is possible. In Class II, which usually includes slightly larger units, the possibilities are somewhat greater, but there is also no room for large-scale investments. The situation is different in Class III, which includes large urban areas. There is relatively much room for expansion there. Due to the high population density, however, vacant land should not only be used for building development, but also for other areas of public space such as parks and squares. Developing all available space can result in overcrowding and increased urban disturbance.

The development zone included villages in Classes IV and V. They are characterized by a moderately developed urban structure and medium or low, by WMA standards, population density. Class IV is mainly represented by the seats of the municipalities relatively distant from Warsaw (Błonie, Tłuszcz) or residential towns (e.g., Konstancin-Jeziorna, Marki). They mostly have some opportunities for expansion. Class V mainly includes villages located in the vicinity of Warsaw or other cities in the most urbanized zone. Their structure is largely the result of the development and sprawl of these cities. They fulfil mainly a residential function, to a large extent that of the City-Gardens (e.g., Józefów, Podkowa Leśnia) and similar settlements (e.g., Komorów, Międzyborów, Zalesie Górne). Due to their small size, they have little scope for further expansion. However, due to their development potential and lack of overcrowding, it can be concluded that at least some of them will continue to develop as long as their area allows.

Classes VI, VII, and VII are mainly characterized by a development and infrastructure structure that is not yet fully formed. Population density varies here, but there are no very densely populated settlements. Class VI is distinguished among these units primarily by its large area and the associated space ready for development. These are mainly towns and villages with an urban character occupying large areas. Class VII includes villages that lie adjacent to more developed settlements and are well connected to them, as well as villages where urban settlements are being developed among rural areas. The units are relatively small, but the population density and area of vacant land vary. Five very low-density settlements make up Class VIII. These are small settlements in peripheral areas away from larger urban centers. The group of settlements above is a zone of possible development that complements the more-developed zones.

Villages classified as IX and X are on the periphery of more-developed centers, constituting a zone intended for development only after neighboring resources are used. Their only asset is their proximity to units in classes I–V. The population density here is very low, and the urban and infrastructural structures are insufficient. They are divided into settlements with considerable spatial potential (Class IX) and somewhat smaller opportunities (Class X). They are a kind of buffer zone for urbanized areas, which can be developed with increased financial resources and property price cuts, which may not be profitable at present. Nonetheless, they act as urban hinterlands in the event that the resources of neighboring centers are fully utilized.

The exclusion zone consists of settlements located in the WMA but not urbanized. Due to their remoteness from urban centers and the lack of a developed urban structure, development in these areas is not advisable, at least not in the near future. This is the largest group of settlements in the WMA and is divided into three classes:

-

agricultural (XI): with high urban potential

-

agro-forestry (XII): with low urban potential

-

forest and protected (XIII): with construction activities prohibited due to location in forest or protected areas.

The urbanized area of the WMA takes on the character of a ring from which urban corridors located along transport routes diverge radially. This is in line with the assumptions about the area’s development set out in the planning acts. However, the ring surrounding Warsaw is still incomplete, and a large part of its suburbs is occupied by strictly agricultural or simply sparsely populated areas.

The most visible corridor is the Warsaw – Vienna railway line, stretching from Piastów through Pruszków, Grodzisk Mazowiecki, and Żyrardów. Urbanization here is enriched by the same course of voivodeship road No. 719. To the south, the urban corridor stretches along national road No. 79 and the Warsaw – Radom railway line. It is slightly shorter than the example described earlier. It consists of Mysiadło, Józefosław, Piaseczno, and Zalesie Górne, among others. Between the two corridors mentioned above, two national roads flow into Warsaw, S8 and DK7, which certainly influence the level of development of the units located there. One strongly developed corridor is the stretch along the S8 road, but on the other side of Warsaw in a northeasterly direction. It is also a stretch of the Warsaw–Bialystok railway line, and the most-developed centers are Ząbki, Kobyłka, Wołomin, and tiny Lipinki. Less visible directions are northern (Legionowo) and eastern (Sulejówek). They consist of very few units and do not extend further than a dozen or so kilometers from Warsaw. Even more modestly outlined directions are western (Ożarów Mazowiecki) and northwestern (Łomianki), where single units dominate, and southeastern (Józefów, Otwock), where there is no strongly urbanized center.

In addition to the aforementioned corridors, a kind of island of developed urban centers can also be observed in the agglomeration. These include Mińsk Mazowiecki and Mrozy to the east of Warsaw, Tłuszcz and Letnisko Nowy Jadów in the northeast, Nowy Dwór Mazowiecki and Nasielsk to the north, Błonie to the west of Warsaw, and, in part, Żyrardów on the southwestern edge of the agglomeration.

The growth of agglomerations and the development of these units mean that some centers have their own residential suburbs. Such centers may include both towns located in corridors (e.g., Piaseczno, Grodzisk Mazowiecki, Legionowo, Wołomin) and islands (Mińsk Mazowiecki, Żyrardów). The development of infrastructure, including public transport and access to public services, creates peculiar agglomerations within one large metropolis. This, in turn, gives the illusion of independence in relation to the capital city, turning more-developed units into self-sufficient centers of the Edge City type.

3.5. Summary of the Results

The main output of the work, the typology of the localities themselves, reflects the ways in which the localities are spatially developed. It also makes it possible to trace the spatial development directions of the towns and their estimated development potential. Urban clusters and corridors constituting centers of urban development have also been identified.

The ring surrounding Warsaw is incomplete (Figure 8). There are undeveloped areas between the individual centers, partly due to the presence of protected areas (Kampinos National Park to the northwest and Mazowiecki Landscape Park to the southeast) and forested areas (the wooded town of Zielonka on Warsaw’s eastern border and the forests surrounding the capital to the north). Despite the presence of areas prohibited for development, there are some development opportunities there. However, they may never be used, which seems to be the most sensible thing to do. Some of the villages adjacent to Warsaw are, however, still incompletely developed, providing a potential demographic and urban base. There are, however, localities with very intensive development associated with the presence of the main exit roads from Warsaw (the S7 road towards Katowice and the road to Sochaczew at the S8 route junction). In addition, the most-developed localities are located at the exits of the corridors (northwest, southwest, south, east, and northeast).

The best-developed corridor is the string of cities and towns in the southwestern direction. The two developed nodes here are Pruszków and Grodzisk Mazowiecki, the latter, together with the surrounding towns, being more developed than the model described at the beginning of the article would suggest. Both centers are linked by a group of moderately and highly developed towns. The third center is Żyrardów on the edge of the agglomeration.

The northeastern corridor is dominated by two nodes—Wołomin (with Kobyłka) and the slightly less-developed Tłuszcz. Compared to the previous corridor, the centers are not connected and are surrounded by settlements from the developing (with a minor exception) or adaptation zone. The densely built-up village of Letnisko Nowy Jadów appears as the third center on the edge of the WMA.

In the eastern direction, the first node is Halinów, although its function may also be performed by Warsaw’s neighbor, Sulejówek. The second node is Minsk Mazowiecki, which, relative to theoretical assumptions, is a more-developed center. There is also a strong center at the border of the WMA in Mrozy. The centers are not connected, but an adaptation zone is slowly forming between them. The northern corridor, in theory, consists of Legionowo, Nowy Dwór Mazowiecki and additionally Nasielsk. The course of the railway line means that this direction is not perfectly straight. In the case of the latter two towns, the role of nodes is taken over by Pomiechówek and Nowe Pieścirogi respectively. The Nasielsk railway station is located in Nowe Pieścirogi and the densely built-up village itself has a great connection to the city. In the case of Nowy Dwór Mazowiecki, its development is stimulated by the vast area of the airport and rivers (the Vistula and Bugo-Narew), while Pomiechówek, devoid of excluded areas, is densely built-up. However, this does not change the fact that both towns (Nasielsk and Nowy Dwór Mazowiecki) are poorly developed in relation to their fairly large areas. Only Legionowo in this corridor has its own agglomeration, which, however, does not connect either to other centers or to Warsaw, mainly due to a string of forests separating it from other centers).

The southern corridor constitutes one node in Piaseczno. This city also has a growing and developed sphere of influence. The second theoretically should be in Czachówek (Gabryelin railway station), where there is a railway junction, but this is not the case. Partly the presence of the Chojnowski Landscape Park hinders development, which separates the Piaseczno agglomeration from the Czachówek area, and partly the undevelopment of the second railway line (Skierniewice—Terespol), which is currently only freight. The lack of development is certainly also influenced by the lack of a main road that would connect Czachówek to Warsaw. Indeed, such a road (DK79) leads to the slightly more-developed Góra Kalwaria.

Ożarów Mazowiecki and Błonie form nodes in the western corridor. Although they are themselves model cities, they do not form assumed surrounding zones and do not connect with each other.

The least-developed of the railway corridors, on the other hand, is the southeastern route. In this case, the first center should be Otwock. Due to the numerous forests, including the Mazovian Landscape Park, which make up a large area of the town, the center does not appear to stand out from the entire agglomeration and is even worse than the neighboring Józefów. It lacks another junction, which theoretically should be located at the level of Celestynów. This is because further possibilities are reduced by the Mazovian Landscape Park extending almost to the border of the WMA.

The northwestern direction, which was supposed to have a road alternative due to the lack of a railway line, in principle does not form any junction except for the developed Łomianki. This may mean that the mere presence of the expressway will not provide as many opportunities as the railway line, or that the presence of a neighboring park (Kampinos Park) strongly stimulates the conditions for expansion. Although the development along the S7 route itself is significant and includes several villages, it is difficult to speak of the creation of an urban corridor, especially one connected to another important center.

The above shows that the agglomeration is not growing perfectly in relation to the adopted model, but it is maintaining its key assumptions. The process of WMA development is ongoing and, although stimulated by a number of natural and legal factors, will continue. The zones described will grow and change in area. It is therefore important to monitor the situation and adhere to assumptions similar to those described above. Accordingly, the study should be repeated from time to time to renew the regulation. A five-year cycle is the most sensible, as this is currently the length of the term of office of local authorities in Poland.

4. Discussion

From the results of the study presented in this article, it appears that Scenario 1, described in 2012 by Grochowski et al. [29], which assumed agglomeration growth rather than regression by 2025 (Figure 9), has come true. This is mainly seen in the northeast and southwest directions. The latter has grown much more than the authors predicted in recent years, and there is no observable deceleration of this process.

In relation to the zones assumed in the WMA Spatial Plan Study, in which seven rail-related corridors were also designated, some discrepancies can be noted [6]. This is mainly due to the fact that the development itself was measured by the Mazovian Regional Planning Office in not entire localities. In the case of the study, one can see continuity of development in the eastern and western directions (Figure 10). However, the analysis of the localities did not show consistency in these directions. This may mean that the settlements may be developed more in the future than the study assumes. In addition, the southeast corridor is highly urbanized, which, for the reasons described above, was not a criterion for the development of the towns and villages there. Attention should also be paid to the land adjacent to the southwest corridor, which is marked as excluded from development in the study. In fact, this is an area that is currently under strong urban development and, as shown in this study, should be developed further due to the depletion of urban resources in the corridor.

Degórska’s study of typical development in the WMA [28] shows six landscape types (Figure 11). Similarities to the results obtained in this study can be seen here, especially in the case of undeveloped land, which in Degórska’s case has a field character (cluster I) and urbanizing land in agricultural areas (cluster II). Despite the detailed research, however, the study is less accurate because the calculations were made for municipalities where, depending on the part, the development may vary. By looking at the localities themselves, it was possible to assess not only the development of the units themselves, but also to estimate their development potential.

The analysis of the results obtained allows us to conclude that the WMA meets the model assumptions of the metropolitan area to a certain extent. As described in Section 3.5, the metropolitan area model assumed in the study is partially developed, but its evolution is still ongoing. When we look at other, relatively simpler models, some convergence can be seen. The urban areas model presented in the PLUREL project [17] predicted the presence of buffers of suburban and agricultural character (Figure 12). The analysis of partial indicators on land use (Figure 5) showed that urban areas are surrounded by agricultural and forest areas, and the study of population density illustrated a gradual decrease in population with distance from cities towards agricultural and forest areas (Figure 4). Given the number of developed cities, the WMA resembles a polycentric model more than a monocentric one.

At the same time, the described research makes it possible to identify settlement units that fit the assumptions of the model settlements. Well-developed transportation and availability of services make it relatively possible to speak of the units classified as I–V (Figure 7) as 15-min cities, or at least these units meet some of the model-related assumptions. The distribution of the units along the railroads suggests their similarity to TND and TOD, but this would require a more in-depth study.

Instead, the Urban Boundary Model is more pronounced as the best-performing units are located at transportation hubs, and the level of unit development weakens with distance from rail lines. The Rural Boundary Model is also notable for its high scores among units located along rail lines. However, there is a lack of transverse corridors connecting the railroad routes to each other.

5. Conclusions

This work sheds new light on the study of the development directions of metropolitan areas by using studies of basic units in the form of statistical localities, which were previously difficult to measure. Although the typology did not show the degree of WMA development assumed in the model, attention should be paid to their accuracy related to the aforementioned use of localities (often planning precincts).

The analysis presented in the article is theoretical in nature. It is related to the development concepts of entire municipalities adopted by local authorities. There may be certain priorities in one part of the municipality that may affect investment in another part of the municipality. It all has to do with the very nature of the municipality, its area, location, and available funds. Therefore, not every municipality will expand its urban space, even if it has favorable conditions for doing so. Not every unit that lacks the conditions to develop will remain stagnant. Indeed, it is possible to transform the current structure, which may barely be noticeable in this analysis due to the non-changing effect of the parameters considered—when the project involves reorganizing and modernizing existing settlement patterns without territorial expansion and the population density remains the same.

Irrespective of the above, this study is a starting point for further research into the individual units, and in a more detailed context, as well as the metropolitan area as a whole. Most importantly, it may become the basis for the creation of the long-awaited Development Plan for the Warsaw Metropolitan Area. This is because the typology provided may have an impact on the regulation of development directions in the area.

The mechanism for performing the typology is also applicable to other urban complexes in Poland. It provides an opportunity to assess the settlement units in each agglomeration in the country, which in turn will enable further work in the field of spatial planning and socio-economic development of municipalities.

Trying to apply this methodology outside Poland may be different. Each country has its own specificities in terms of land use and infrastructure development, as well as its own priorities. In some countries, there is no public transport even in large metropolitan areas. In others, there is a deficit of paved roads, even in densely populated cities. On the other hand, there are regions in Europe with a strictly agricultural character where public transport is very well functioning.

Just as the above methods can be said to be universally applicable in Poland, parametric changes may be required in order to use them in other countries. However, the essential core of the study is the structure of the survey, which can be transferred to any part of the world.