Visibility Analysis to Enhance Landscape Protection: A Proposal of Planning Norms and Regulations for Slovakia

Round 1

Reviewer 1 Report

Interesting and original research, it could have many applications also in Cultural Heritage Protection. I suggest to authors to enlarge the study in the future considering also CH sites and historical cities locations. By the moment these issues could be mentioned in the conclusion as one of the possible development of the research. The paper is clear and well organized and the methodology could be easily applied to other Countries.

Author Response

Interesting and original research, it could have many applications also in Cultural Heritage Protection. I suggest to authors to enlarge the study in the future considering also CH sites and historical cities locations. By the moment these issues could be mentioned in the conclusion as one of the possible development of the research. The paper is clear and well organized and the methodology could be easily applied to other Countries.

Author’s comment:

Thanks for the positive reaction!
We have added some comments about the inclusion of cultural heritage as a possible development of the research at pag. 14, lines 421-426.

 

Reviewer 2 Report

The authors addressed visibility analysis of the entire landscape of the Slovak Republic from the network of main national roads. This work is of practical value in supporting the development of local planning norms and regulations at the national level. However, the following questions remain for improvement.

Abstract：

1.The authors should summarize clearly what the novelty or contribution of this work is, or what is the difference/superiority of this work compared with the existing methods, especially in the abstract and introduction section.

2.In the abstract part, there is a lack of quantitative data expression in the description of the research results.

Introduction：

3. Does the analysis is considered in the discussion, conclusion section. (lines 58-60)

4. Introduction need the inventory of the studies reviewed. This part needs more extensive works to synthesize current research and find any research gap to contribute landscape protection.

Materials and Method：

5.Please provide the source of the road data in the Materials section. (line 89)

6. What is the basis for this, for clarity, more explanation is required. (Lines 118-122)

7. Please give more explanation or proof as to why it is 400m. (lines 124-126)

8. LULC-related data were used in the study and why they were not expressed in the mapping. (lines 208-213)

Results：

9. The standard of mapping should be consistent, and we recommend that each map is preferably oriented with a compass, preferably keeping the same specification for each map in the text. (lines 242)

10. In a study where common units need to be consistent, Table 2 is km² and Table 3 is ha, with suggested changes. (Lines 251)

11. Suggestions for standardized mapping. (Line 266)

12. Which area is shown in detail on this map and what is the meaning of the grey scale map in terms of elevation? Please give a legend to illustrate this.( lines 269)

Discussions:

13.Please add a source for this statement. (Lines 329-331)

References:

14.Some references still have errors in their format and corrections are recommended, e.g. Jeffrey Wilson, Greg Lindsey & Gilbert Liu (2008) Viewshed characteristics of urban pedestrian trails, Indianapolis, Indiana, USA, Journal of Maps, 4:1, 108-118, DOI: 10.4113/jom.2008.1014 (Lines 438)

language:

15. The language expression of the full text should be further improved, paying attention to the structural logic and the cohesion between the contexts.

Author Response

The authors addressed visibility analysis of the entire landscape of the Slovak Republic from the network of main national roads. This work is of practical value in supporting the development of local planning norms and regulations at the national level. However, the following questions remain for improvement.

Abstract：

1.The authors should summarize clearly what the novelty or contribution of this work is, or what is the difference/superiority of this work compared with the existing methods, especially in the abstract and introduction section.

Author’s comment:

The main novelty of the contribution relies on the possibility of deriving different and articulated planning indications/prescriptions for the protection of the landscape for large geographical contexts (i.e. entire Countries), using a limited dataset and therefore maximizing the transferability of the method.

We have summarized these points in the abstracts (pag. 1, lines 28-29) and in the introduction (pag. 2, lines 82-85)

 

 

2.In the abstract part, there is a lack of quantitative data expression in the description of the research results.

Author’s comment:

We have updated the abstract with some summary of results in pag. 1, lines 23-26.

 

Introduction：

3. Does the analysis is considered in the discussion, conclusion section. (lines 58-60)

Author’s comment:

Results from visibility analysis have been extensively commented both in discussions (pag. 12-13, lines 294-371) and conclusions (pag. 15, lines 440-446).

 

4. Introduction need the inventory of the studies reviewed. This part needs more extensive works to synthesize current research and find any research gap to contribute landscape protection.

Author’s comment:

Main researches about different applications of visibility analyses have been reported at the beginning of the introduction, at pag. 1-2, lines 34-53.

Research gap is about the actual use of visibility analysis to planning protection, which is the main objective of this research. This point and the innovation of the work have been better clarified in page 2, lines 76-84.

 

Materials and Method：

5.Please provide the source of the road data in the Materials section. (line 89)

Author’s comment:

Source of data are reported in pag. 4, lines 126-128.

 

6. What is the basis for this, for clarity, more explanation is required. (Lines 118-122)
7. Please give more explanation or proof as to why it is 400m. (lines 124-126)

Author’s comment:

We have tried to avoid too long computation times for the elaboration of the viewshed, as different tries were needed to analyze the results obtained (see table below, indicating computing times). Furthermore, 50 meters DTM and a distance of 400 meters was considered a good compromise considering the extent and aims of the research. We have rephrased the sentence, adding more information (pag. 4, lines 137-139.

Viewpoints	DEM	Processing Time
16	20x20	6 hours
16	50x50	4 min
1958 (roads sampled every 400 m)	20x20	> 24 h,
1958 (roads sampled every 400 m)	50x50	~ 5 h, 50 min
7832 (roads sampled every 100 m)	50x50	> 24 h,

 

8. LULC-related data were used in the study and why they were not expressed in the mapping. (lines 208-213)

Author’s comment:

 We did not include specific maps of LULC as these were not necessary (so to avoid too much information in figures). LULC data was needed to understand in more quantitative and statistic terms which LULC categories were actually the most visible at the national level, as reported  in table 2.

 

Results：

9. The standard of mapping should be consistent, and we recommend that each map is preferably oriented with a compass, preferably keeping the same specification for each map in the text. (lines 242)

Author’s comment:

Norh arrow has been included in fig. 2, 3, 5, 6

 

10. In a study where common units need to be consistent, Table 2 is km2 and Table 3 is ha, with suggested changes. (Lines 251)

Author’s comment:

The reason for this is due to the difference in terms of areas involved: table 2 accounts for the statistics for all the LULC at the national level, while table 3 reports the size of LULC categories included in the different planning norms, which are quite more limited in size.

 

11. Suggestions for standardized mapping. (Line 266)

Author’s comment:

Fig. 9  modified

 

 

12. Which area is shown in detail on this map and what is the meaning of the grey scale map in terms of elevation? Please give a legend to illustrate this.( lines 269)

Author’s comment:

The detailed frame cannot be made not visible in the bigger map at this scale, as it represents a little portion of the landscape. However, the small frame is to be intended as an example of the relation among the H_lim1 and H_lim2 norms.

The grey area is the hillshade, so it doesn’t require to be included in the legend.

 

Discussions:

13.Please add a source for this statement. (Lines 329-331)

Author’s comment:

Added accordingly

 

References:

14.Some references still have errors in their format and corrections are recommended, e.g. Jeffrey Wilson, Greg Lindsey & Gilbert Liu (2008) Viewshed characteristics of urban pedestrian trails, Indianapolis, Indiana, USA, Journal of Maps, 4:1, 108-118, DOI: 10.4113/jom.2008.1014 (Lines 438)

Author’s comment:

We have corrected some references, however a final revision of the list of References will be done at the final stage of the editorial process by MDPI staff.

 

language:

15. The language expression of the full text should be further improved, paying attention to the structural logic and the cohesion between the contexts.

Author’s comment:

We have revised again the text and corrected typos and languages issues.

Reviewer 3 Report

This paper looks into using visibility analysis to improve landscape protection. The article is lacking in both innovation and scientific validity. My primary comments are:

-Line 101 “The first step of the definition of Landscape Types included the creation of the basic spatial units - morphological-positional types of the landscape- which formed the basis for its further classification and evaluations. The second phase consisted in the reclassification of geomorphological units and morphological-morphometric types of relief specified by a digital relief model.” Based on what did you propose these steps?

-Line 209 “First, the values of cumulative viewshed raster were assigned to features of Land-use/Land Cover (LULC) of the level 3 of Corine Land Cover (EEA, 2018) with zonal statistics function.” Why do you use CLC datasets? Please provide more information about the CLC.

-Line 211: “LULC data was preferred over landscape types used in the previous step of the analysis for their higher 212 resolution (minimum mapping unit equal to 25 ha).” So, is it appropriate to analyze the viewshed of a landscape with such an MMU (25ha)? Numerous detailed land uses/covers are lost with high MMU, resulting in erroneous conclusions.

Author Response

This paper looks into using visibility analysis to improve landscape protection. The article is lacking in both innovation and scientific validity. My primary comments are:

-Line 101 “The first step of the definition of Landscape Types included the creation of the basic spatial units - morphological-positional types of the landscape- which formed the basis for its further classification and evaluations. The second phase consisted in the reclassification of geomorphological units and morphological-morphometric types of relief specified by a digital relief model.” Based on what did you propose these steps?

Author’s comment:

This section summarizes the main steps implemented in a previous research about landscape classification of Slovakia, that is used, but not developed, by this research,. Since the landscape classification is important for the rest of the research, we wanted to give a brief overview of the method used. We added a line to clarify this point (page 3, lines 110-111).

 

-Line 209 “First, the values of cumulative viewshed raster were assigned to features of Land-use/Land Cover (LULC) of the level 3 of Corine Land Cover (EEA, 2018) with zonal statistics function.” Why do you use CLC datasets? Please provide more information about the CLC.

Author’s comment:

We have used LUCL data to identify more precisely the areas (in terms of LULC categories) impacted by the proposed planning norms. In other words, we wanted to understand the relation between the current use of the land and the proposed norms.

This allows to have a more grounded idea of possible limitations, constraints and conflicts for the actual implementation of the norms.

We have added some lines to clarify the reasons of the use of LULC in (page 6, lines 222-225).

 

-Line 211: “LULC data was preferred over landscape types used in the previous step of the analysis for their higher 212 resolution (minimum mapping unit equal to 25 ha).” So, is it appropriate to analyze the viewshed of a landscape with such an MMU (25ha)? Numerous detailed land uses/covers are lost with high MMU, resulting in erroneous conclusions.

Author’s comment:

Thanks for this important comment.

LULC data has better resolution than landscape units data, that’s why we preferred to use this geo-data to understand (as explained in previous comment) the relation between the proposed norms and the LULC category.

It is true that the MMU is not small, but it depends on the CLC data used, which is the only source of vector LULC data available for the entire country. However, It should be reminded that this is nation-wide research, so the use of such data is consistent with the extent of the study area.

Reviewer 4 Report

Dear authors, only a few comments in order to increment the quality of your manuscript:

1.- References cited throughout the text, following the formatting standards of MDPI, should be in numerical order, not specifying the surname and year of each author.

2.- In results, please make a composite that joins figures 7, 8, 9 and 10, and do not put them separately. 

3.- Seccion 4. Discussion (remove the final s): this section should be reviewed in depth. There are hardly any bibliographic citations to support their results. The organization of the discussion seems fine to me, but they should write how their results agree or disagree with those of other studies, hypothesizing the reasons. Similarly, they should include a section specifying the main limitations of their results.

Kind regards,

Author Response

Dear authors, only a few comments in order to increment the quality of your manuscript:

1.- References cited throughout the text, following the formatting standards of MDPI, should be in numerical order, not specifying the surname and year of each author.

Author’s comment:

We have corrected some references, however a final revision of the list of References will be done at the final stage of the editorial process by MDPI staff.

 

2.- In results, please make a composite that joins figures 7, 8, 9 and 10, and do not put them separately.

Author’s comment:

In a first version of the manuscript we have included a single map (we agree that it would make more sense to have one map), but then we found out that the single smaller maps didn’t allow a correct visualization of details. For this reason, to increase the readability of the figure and as also suggested by another reviewer, we have split the figure into separated maps.

 

3.- Seccion 4. Discussion (remove the final s): this section should be reviewed in depth. There are hardly any bibliographic citations to support their results. The organization of the discussion seems fine to me, but they should write how their results agree or disagree with those of other studies, hypothesizing the reasons. Similarly, they should include a section specifying the main limitations of their results.

Author’s comment:

We agree with the reviewer that the discussions comment the results obtained, but they can rely only to a limited extent to existing studies, because we could not find many researches that made use of visibility analysis to identify planning norms, which actually represent the main innovation of our work.

That’s why we have organized the discussion into sub-sections that critically comment the results obtained (especially in terms of the relation between planning norms and current asset of land use land cover) and the limitations and possible improvement of the methodology.

However, we have added new references to better frame the results and related discussion at the light of current literature (page 13, lines 337; page 13, line 350; page 13, line 371).

 

Round 2

Reviewer 2 Report

The authors addressed previously raised comments and improved the manuscript (e.g. Figure and formats of articles). Improved quality of papers, I think it can be allowed to be published in land.

Author Response

Thank you for your positive comments.

 

Reviewer 4 Report

Dear authors, a few comment to improve your manuscript:

1.- Abstract: please remove the capital letters in "Glacial mountains", "Plane depressions", and "Wide alluvial plains".

Moreover, my previous comments have been addressed. Kind regards, 

Author Response

Thank you for your positive comments.

 

1.- Abstract: please remove the capital letters in "Glacial mountains", "Plane depressions", and "Wide alluvial plains".

Authors' reponse

We have revised the abstract accordingly.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript is well-written and fits well both the scope of the journal and SI. The study deals with novel and interesting topic in Landscape Ecology – applying of landscape visibility to landscape planning and conservation. The study emphasis the visibility of very important attribute of landscape in national scale based on case study from central-European country. This case is appropriate for this type of landscape analyse because of European cultural landscapes are very variable and thus interesting for viewshed analyses. I highly appreciate this study provided a good example of innovative using of presented methodological approach (based on GIS support, of course). I have only some minor comments to the manuscript as follows:

• I am not sure that Authors precisely follow all rules of the Land journal related to format of manuscript. It should be seriously corrected.
• Title of the manuscript should be shortened. Two long sentences as a title seems not to be appropriate.
• Section Abstract should be added (i) by a brief description of methods and (ii) statement related international importance/portability of original results.
• There is missing a clear definition of main targets of the study in the end of the section Introduction.
• In the section Methods, Authors should add a clear definitions of main key terms of the study (visibility, viewsheds etc.). Also, more details about “viewshed analysis” should be added (subchapter 2.3). By the way, Authors should explain to international readers what is “LULC” including relevant citation.
• Section Results can be reworked (rephrased to better form) – in current form, this section is written as detailed comments to figures; but figures should present additional (not main) information in scientific study. Also, Authors should better highlighted main original findings of the study.
• Section Discussion is too short and constrained predominantly to discussion related to LULC. This section should be extended using more recent literature cited related to the study topic. Also, a discussion related to uncertainties in data sources and methodology used should be added.

Some terms in English are not probably correct and should be checked if English language is correct (“Country”, the Capital city” etc.).

Author Response

The manuscript is well-written and fits well both the scope of the journal and SI. The study deals with novel and interesting topic in Landscape Ecology – applying of landscape visibility to landscape planning and conservation. The study emphasis the visibility of very important attribute of landscape in national scale based on case study from central-European country. This case is appropriate for this type of landscape analyse because of European cultural landscapes are very variable and thus interesting for viewshed analyses. I highly appreciate this study provided a good example of innovative using of presented methodological approach (based on GIS support, of course). I have only some minor comments to the manuscript as follows:

I am not sure that Authors precisely follow all rules of the Land journal related to format of manuscript. It should be seriously corrected.

Author’s comment:

The article has been automatically formatted by the MDPI system, and will be typeset in the final form after its final revision.

 

Title of the manuscript should be shortened. Two long sentences as a title seems not to be appropriate.

Author’s comment:

 We agree that 2 lines can be slightly longer than usual but we believe they are needed to capture the nature and objectives of the research at a first reading

 

Section Abstract should be added (i) by a brief description of methods and (ii) statement related international importance/portability of original results.

Author’s comment:

Abstract has been changed accordingly (pag 1, lines 15-16; lines 23-25)

 

There is missing a clear definition of main targets of the study in the end of the section Introduction.

Author’s comment:

 Objectives of the research have been explicitly stated in page 2, lines 71-75

 

In the section Methods, Authors should add a clear definitions of main key terms of the study (visibility, viewsheds etc.). Also, more details about “viewshed analysis” should be added (subchapter 2.3). By the way, Authors should explain to international readers what is “LULC” including relevant citation.

Author’s comment:

Key terms have been better introduced. For example more details about the concept of visibility have been added in the introduction section (page 1, line 39-42). The concept of viewshed has been better defined and introduced in the method section 2.3 at  page 4, line 131-135.

LULC acronym is clarified in page 6, line 211.

 

Section Results can be reworked (rephrased to better form) – in current form, this section is written as detailed comments to figures; but figures should present additional (not main) information in scientific study. Also, Authors should better highlighted main original findings of the study.

Author’s comment:

We are sorry that in the previous version of the manuscript the heading of sub-section 3.1 was missing and this has probably generated some confusion in the organization of the discussion section.

Results follow sequentially the method structure, presenting the result of viewshed analysis (section 3.1), spatial statistics (section 3.2) and planning norms that are originated by the visibility analysis (section 3.3). We opted to keep this sequential order to increase the logical flows of arguments and results.

We think that the results are not just replicating what mapped in the figures, as they include the statistics which allow to understand the extent of the different types of landscape that can be visible (tables 2 and 3 represent a quantitative synthesis of the maps).

The original findings have been indicated and commented extensively in section 4.1 with reference to the normative implications for landscape protection with several examples (page 12-13, lines 277-339).

 

Section Discussion is too short and constrained predominantly to discussion related to LULC. This section should be extended using more recent literature cited related to the study topic. Also, a discussion related to uncertainties in data sources and methodology used should be added.

Author’s comment:

Discussion section has been re-organized in 2 sub-sections. The 1^st subsection is not only about LULC but it discusses some different proposal of norms and regulations according the intersection of LULC categories and level of visibility. The second sub-section, as requested by the reviewer, also includes the discussion of limitations (which have been further extended, see page 13, lines 371-380).

Other paragraphs about the relation with European Landscape Convention (page 13, lines 340-355) and limitations of the methodology have been added (and page 14, lines 393-398).

 

Some terms in English are not probably correct and should be checked if English language is correct (“Country”, the Capital city” etc.).

Author’s comment:

Dealing with geographical topic, we think the use of “country” is a correct choice. However, in some instances it was changed.

 

 

Reviewer 2 Report

The article touches on an interesting problem. However, a relatively subjective determination of classes for the choropleth map and the quantitative area maps as well as the land use map and categories, norms of visibility  – require an objective analysis and description using examples.

While the research process is properly described, there is no indication of the cartographic method as the basic method in this research of the actual research effect. The term 'map' is missing from the keywords.

In the 'introduction' section, in addition to the main goal, the stages of research (research scheme), source materials and cartographic and indicative effects of individual steps should be indicated. There is no guidance for specific stages of these studies in terms of implementing the requirements of the European Landscape Convention and the protection of individual landscape types.

The knowledge concerns the literature on landscape management, the GIG technology is also appropriate, but the lack of objective features of the result maps. Quantitative maps - choropleth maps here - are poorly prepared. In order to validate the results, the authors should properly describe the spatial distribution of the adopted indicators on the basis of the mapping methods used. Color scales need to be corrected.

Successive maps should be listed and the information that these maps present. Maps for the visualization of quantitative and qualitative data.

Figure 1. – maps of Landscape types – who developed this type map? Why is there no logical color matching –  so that the reader can at least make a visual analysis?

The 'result' section lacks an objective analysis and examples confirming it resulting from this research procedure. What are relationships between figures and tables?

Figure 5.The same enlarged fragment in this figure – should be shown on the others and describe whether it relates to a universal analysis or the one specific for Slovakia?

Figure 7. – maps are illegible and difficult to compare – neither simple relations concerning the specificity of Slovakia's landscape nor areas for universal interpretation for similar landscapes in European countries can be seen.

In the 'discussion' section, you should use the results, that is maps, tables and examples confirming the assumptions and examples showing the specificity of landscape visibility. The 'discussion' section should not be broken down into one subsection.

Author Response

The article touches on an interesting problem. However, a relatively subjective determination of classes for the choropleth map and the quantitative area maps as well as the land use map and categories, norms of visibility  – require an objective analysis and description using examples.

Author’s comment:

We agree with this comment, but it is very important to underline that the classes have been used only to produce the maps (intended as a cartographic representation of the cumulative viewshed). Nor results by the visibility analysis or by the spatial zonal statistics are influenced by those classes, as these results are relying on actual scores of visibility (in terms of real number of visible points) and related actual size (in square KM) of the different categories of landscape types (table 2) and land-use/land cover categories (table 3).

However, to avoid any misunderstanding, this comment has been added in the discussion section in pag. 14, lines 399-404

 

 

While the research process is properly described, there is no indication of the cartographic method as the basic method in this research of the actual research effect. The term 'map' is missing from the keywords.

Author’s comment:

As reported in the previous comment, there is no real effect of the method used to determine the classes for the choropleth map on the results.

However, we have added information about algorithm used for the mapping in the caption of fig. 1.

Keywords have been updated with the word maps.

 

In the 'introduction' section, in addition to the main goal, the stages of research (research scheme), source materials and cartographic and indicative effects of individual steps should be indicated. There is no guidance for specific stages of these studies in terms of implementing the requirements of the European Landscape Convention and the protection of individual landscape types.

Author’s comment:

All used data, sources and materials have been presented in section 2.1 Landscape Types of Slovak Republic and 2.2 Data Availability.

We have added some reflections on the contribute of the research to European Landscape Convention in the discussions, specifying how the results can be used by the national landscape planning processes to meet the requirement of the Convention (page 13, lines 340-355)

 

The knowledge concerns the literature on landscape management, the GIG technology is also appropriate, but the lack of objective features of the result maps. Quantitative maps - choropleth maps here - are poorly prepared. In order to validate the results, the authors should properly describe the spatial distribution of the adopted indicators on the basis of the mapping methods used. Color scales need to be corrected.
Successive maps should be listed and the information that these maps present. Maps for the visualization of quantitative and qualitative data.

Author’s comment:

Please see the previous comment about the maps and their relation (actual no relation!) with results.

We believe that color scales used are correct, as they represent:

• A qualitative variable (Categories of landscape), fig. 1: unique colors
• an increasing continuous variable (the DTM), fig. 2: color ramp
• an increasing continuous variable (the number of visible point), fig. 5: 5 classes color from red (low visibility) to green (high visibility)

 

Figure 1. – maps of Landscape types – who developed this type map? Why is there no logical color matching –  so that the reader can at least make a visual analysis?

Author’s comment:

The map has been produced by the authors based on the book  

Bezák et al. Representative landscape types of Slovakia. Bratislava: Institute of Landscape Ecology SAS, publishing company VKÚ, a.s. Harmanec, 2010, 180 pp., ISBN 978-80-89325-15-3.

The reference has been made more explicitly in pag 3, line 111

 

In fig. 1 An unique color is attributed to each category of landscape type (a categorical variable).

The 'result' section lacks an objective analysis and examples confirming it resulting from this research procedure. What are relationships between figures and tables?

Author’s comment:

In the previous version of the manuscript the heading of sub-section 3.1 was missing and this has probably generated some confusion. Now the sub-section numbering has been fixed, so we hope that the presentation of results is more clear: results follow sequentially the method structure, presenting the result of viewshed analysis (section 3.1), spatial statistics (section 3.2) and planning norms that are originated by the visibility analysis (section 3.3). We opted to keep this sequential order in order to increase the logical flows of arguments and results.

We think that the results are not just replicating what mapped in the figures, as the results include the statistics which allow to understand the amount of the different types of landscape that can be visible (the tables 2 and 3 represent a quantitative synthesis of the maps).

 

Figure 5.The same enlarged fragment in this figure – should be shown on the others and describe whether it relates to a universal analysis or the one specific for Slovakia?

Author’s comment:

The excerpt in the right bottom of figure 5 is of course related to the Landscape of Slovakia and it is located in the middle of the country, as indicated by the rectangular shape. We have made this shape more visible changing the color of its outline to full black.

 

Figure 7. – maps are illegible and difficult to compare – neither simple relations concerning the specificity of Slovakia's landscape nor areas for universal interpretation for similar landscapes in European countries can be seen.

Author’s comment:

These maps represent the geographical location of portion of the landscape of the proposed norms.

To make them more visible we have enlarged them (fig 7- 10)

 

In the 'discussion' section, you should use the results, that is maps, tables and examples confirming the assumptions and examples showing the specificity of landscape visibility. The 'discussion' section should not be broken down into one subsection

Author’s comment:

Discussion sections is organized exactly to comment the results and to propose some practical regulations and norm for the protection of the high level of visibility. Examples are given according to the different combination of types of landscape and score of visibility.

Discussions have also been enriched by new paragraphs about the contribute of the research to the European landscape convention (page 13, lines 340-355) and about some limitation of the methods (page 13, lines 371-380).

We believe that different sub-sections help readers in better differentiate the content of the discussion and also avoid too long section, which would not be easy to read.

 

Reviewer 3 Report

I think that the paper has some potential, but authors should study better viewshed and literature concerned to it. I think that part of the method is wrong, but it could be corrected.

First of all, structure in a better way the paper. For example, in paragraph 2.2 the cumulative viewshed is cited before to explain what it is. The usual format should be:

• Introduction
• Methods
• Case study (this include case study description, data description and numerical parameters introduced in the methods).

Second (the hardest part). I think that part of what you inserted in par. 2.4, GIS analysis is wrong. I understand if authors want to use zonal stats (this is map algebra, that authors doe not cite in the paper) to have landscape units based on viewshed, but this is not enough. The different types of landcover must be inserted previously inside the dtm. I mean that the viewshed analysis needs, to be a correct viewshed, a DSM as input data, not a DTM. Authors can see the following work to clear their ideas about viewshed analysis "Identifying viewshed: new approaches to visual impact assessment"(2011), Danese, Nolè, Murgante. The results, after doing this, will change surely and they will be to evaluate. Authors should Improve also the defition of cumulative viewshed done at the top of par. 2.3.

Author Response

I think that the paper has some potential, but authors should study better viewshed and literature concerned to it. I think that part of the method is wrong, but it could be corrected.

First of all, structure in a better way the paper. For example, in paragraph 2.2 the cumulative viewshed is cited before to explain what it is. The usual format should be:

Introduction

Methods

Case study (this include case study description, data description and numerical parameters introduced in the methods).

Author’s comment:

We believe the structure of the paper is following a traditional template (intro, material/methods, results, discussions, conclusions), which is quite similar to the one proposed by the reviewer. The case study is “naturally” embedded in this structure.

 

Second (the hardest part). I think that part of what you inserted in par. 2.4, GIS analysis is wrong. I understand if authors want to use zonal stats (this is map algebra, that authors doe not cite in the paper) to have landscape units based on viewshed, but this is not enough. The different types of landcover must be inserted previously inside the dtm. I mean that the viewshed analysis needs, to be a correct viewshed, a DSM as input data, not a DTM. Authors can see the following work to clear their ideas about viewshed analysis "Identifying viewshed: new approaches to visual impact assessment"(2011), Danese, Nolè, Murgante. The results, after doing this, will change surely and they will be to evaluate. Authors should Improve also the defition of cumulative viewshed done at the top of par. 2.3.

Author’s comment:

We think the reviewer is talking about the possibility of adding the z-values of land cover to the DTM, to get a more accurate representation of the terrain. We agree with the comment of reviewer, that results of visibility analysis change if a different digital elevation model (DTM or DSM) is used. In the case of this research, no DSM was available and the possibility of adding the z information of land cover to the DTM for the entire Slovakia was not feasible or useful for 2 reasons: first, the extent of the study area would have made this further task extremely time-consuming (and beyond the actual scope of this research); second, no information of height was available in the land cover data and its resolution would have not allowed to add a precise and reliable information of the z for each category of land cover (considering that each category could include feature with very different height). For these reasons, and given the nature and extent of this research, we believe that using a DTM was a good choice to achieve the objectives.

However, we think this is an important point that deserve attention and so we have added it in the discussions (in page 13, line 371-380.)

 

The concept of viewshed has been better defined and introduced in in page 4, line 130-135.

 

Round 2

Reviewer 2 Report

Unfortunately, the authors only partially implemented my comments. I still have the impression that the methodology of this research does not have an objective analysis on specific examples of Slovakia lands.

The use of simple GIS operations - to obtain maps and a tables without examples and reliable synthesis - does not convince me. However, if the editor considers the appropriate quality of the second, only slightly improved version, I do not object.

Reviewer 3 Report

The declared aim of the paper is “to propose appropriate planning norms and regulation to protect the visibility values found”.

1. If authors want to propose planning norms based only on visibility, I think that visibility should at least calculated in the best and more accurate way and, as affirmed by authors “An important part of the procedure is the evaluation of visibility of the real landscape features or landscape types”. Today there are many ways to have DSM (see for example free Copernicus data). Consequently, it is not necessary to construct by itself a DSM. In addition, to replace DTM with an existing DSM is not as much time consuming as declared by authors. Most of all because the presence of objects on the territory could affect very much the visibility on which you planning norms are based and consequently all the results of the paper.
2. Again about visibility values of a territory. Is the visibility values of a territory based only on the visibility from roads? My opinion is that the methodology was too much simplified. What about landmarks? What about visibility from natural panoramic points? Finally (but there could be other elements to consider in the analysis) what about visibility from other elements of the cultural heritage with panoramic view?
3. The planning norms regulates and restricts territorial transformation of a very large area, but with a precision of the indication that only local plans usually have. This could also be possible, but I think this is one reason more to do a more rigorous analysis.
4. Could planning norms be based only on visual values, even if important? I do not think an overlay with land use is enough to this aim. Even if authors cite this in the paper, I think that a more comprehensive suitability analysis should be easily performed. In literature many papers with by the time consolidated methodologies exist to integrate in planning regulations visual values, natural values and other elements.

For all these reasons, I believe the paper is not mature for publication. If authors will work in the directions highlighted, they could improve very much the methodology and the results and try to submit successfully their work.