4.3. Cognitive Maps Perceived by Citizens
SD analysis was combined with a cognitive map method to compare and analyze the familiarity of how citizens perceive the spatial images of different urban forest types.
Figure 3 presents example of hand-drawn cognitive maps. The familiarity of citizens in perceiving urban forest spatial images varied across individuals.
Based on the classification criteria of cognitive maps proposed by Appleyard (1970), the cognitive maps obtained in this study were roughly divided into sequential cognitive maps (including linear, branch and chain cognitive maps), mainly with path elements, and spatial cognitive maps (including scattered, mosaic and connected cognitive maps), as well as regional elements [
43]. A linear cognitive map represents a branch map that includes the main roads inside and around the urban forests of the current study, or a more detailed linear perception map. A branch cognitive map is a branch map that contains the elements of an urban forest that were considered impressive by the interviewees, and could connect the elements through the path. A chain cognitive map was based on the chain map around the main roads of the urban forest. A scattered cognitive map contained a combination of scenic spots or areas with specific impressions, which roughly reflected the perception of the spatial image of an urban forest. A mosaic cognitive map was a combination of different areas of urban forests in the memory of the respondents, so that it could be combined into the perception of the spatial image of an urban forest. Connected cognitive maps were the spatial segments of urban forests connected by the necessary traffic roads and facilities [
48]. The cognitive maps obtained in this study are shown in
Table 5, of which 53.13 were sequential cognitive maps and 46.88 were spatial cognitive maps.
The maximum likelihood method was used to classify the types of hand-drawn cognitive maps based on the individual characteristics of different citizens, and to estimate the degree and significance of their impact. A disordered multivariate logit model was constructed to calculate the types of cognitive maps and compare them. Disordered multiple choice models were used for the calculations because: (1) The six types of cognitive map are arranged disorderly, and the possibility of drawing a particular type of map is also disorderly for citizens; and (2) the function of the selection model used to calculate these problems is similar, but the multivariate Probit model is more complex, so the multivariate Logit model was used. Linear, branched, chain, scattered, mosaic, and connected cognitive maps were set up for Scheme 1 (P1), Scheme 2 (P2), Scheme 3 (P3), Scheme 4 (P4), Scheme 5 (P5), and Scheme 6 (P6), respectively. Schemes 1 and 5 were set as an experimental group and Scheme 6 was set as the reference group. Based on the Wald test results, the final results were obtained by eliminating the variables for which parameter estimates were zero (
Table 6).
Younger citizens had a wider understanding of urban forests. They could generate mosaics the different areas in urban forest in their memory, and draw mosaic-like cognitive maps [
43]. In comparison, the memories of older citizens were weaker, but they visited the urban forests more frequently. Their perceptions of urban forests were more concentrated and focused. Therefore, the image perception of older citizens was embodied in scattered cognitive map.
The connected cognitive map drawn by citizens with a secondary education level (i.e., high school diploma) was a relatively high-level cognitive map, demonstrating that the perceptions of spatial images in urban forest by citizens was closely related to their educational level [
48]. Respondents with fewer elderly family members had less responsibility in caring for the elderly, and more leisure time for activities in urban forest areas. Regarding urban forest regional activities, this segment of citizens has a deep perception of the spatial image of an urban forest, drawing higher levels of connected cognitive maps.
Unmarried citizens drew linear cognitive maps, which was the map type drawn by most respondents. These maps only contained the main roads related to urban forests, representing a shallow type of spatial image perception. The citizens with better physical health had more energy and physical strength, and were generally more active in urban forest areas. Their hand-drawn cognitive maps had a connected and branched style, demonstrating sufficiently deep memories of certain urban forest elements. They could connect these elements through the main traffic roads, to form a generally branch map.
Citizens who had lived in Beijing for 10–15 years could draw a branch cognitive map, whereas those who had lived in Beijing for less than 10 years could only draw a chain cognitive map to obtain a chain cognitive space. Most of the citizens who lived in Beijing for less than three months each year, and who lived between the 5th and 6th Rings, were considered the floating population in Beijing. Their perceptions of the spatial image of an urban forest were relatively concentrated, only drawing the most impressive elements of urban forests as scattered cognitive maps.
The key elements of cognitive maps can be classified based on image elements according to the classification method of Lynch (1960), these maps are primarily and intuitively assessed from the richness of certain elements, including landmarks, paths, nodes, regions, and boundaries [
42]. Landmarks in the current study were reference points provided to the citizens in urban forests, including famous scenic spots and other elements that can be perceived and, potentially, make an impression on citizens. Because this study focused on typical forest parks, suburban parks, and urban parks, which have clearly delineated administrative boundaries, this study separated the landmarks into internal landmarks and external landmarks for research. This study primarily focused on urban forest areas, in which the respondents entered from the actual level and psychological level. The node was where citizens enter areas, with the function of connecting, such as a squares and parking lots. The boundary was the area or location between two regions, such as entrances and exits. The path was the road provided by urban forests, connecting different scenic spots or locations, such as greenways, footpaths, and ropeways. This information was used to generate frequency distribution statistics of the cognitive maps of citizens based on familiar factors.
Figure 4 shows the distribution of familiarity factors in cognitive maps. Overall, citizens were more familiar with the perception of interior landmarks and regional elements of forest parks, the nodes and boundaries of suburban parks, and external landmarks and paths of urban parks.
By integrating familiar elements in the cognitive maps of Xiangshan Park, Summer Palace, and Yuyuantan Park, this study evaluated the familiarity of citizens with the spatial image perception of a forest park, suburban, park and urban park, respectively. Through classifying the six dimensions of cognitive map image elements (i.e., internal landmarks, external landmarks, paths, nodes, regions, and boundaries), the most prominent elements of urban forest types were identified (
Figure 5).
Xiangshan Park represented a forest park, with the prominent internal landmarks being the famous scenic spots. These elements are rooted in the development process of forest parks, and are unique to forest parks, including famous mountains, ancient temples. The geographical locations of forest parks determine the characteristics of their internal markers and corresponding external markers. For instance, Beijing Botanical Garden and Badachu Park are adjacent to Xiangshan Park, reflecting the characteristics of forest parks, namely the remote geographical location, remarkable natural form, and high greening coverage. Because of the unique natural and cultural landscape of forest parks, people place more focus on the main scenic spots due to the time and effort required to access them. Communication through the media and public opinion about famous scenic spots cause citizens to form an a priori sense of familiarity. In contrast, forest parks had a lower level of cognitive familiarity, in terms of paths, nodes, and boundaries. This is because citizens are not focused on the degree of neatness and artificial planning of forest parks. Citizens primarily focused on the ecological environment and landscape services provided by forest parks. Therefore, the elements of paths, nodes, and boundaries tend to be overlooked in the cognitive maps drawn by citizens.
The Summer Palace represented a suburban park, with unique characteristics, in addition to famous natural and historical landscapes, such as Kunming Lake, Seventeen-Cone Bridge, and the Bronze Bull Sculpture. Suburban parks are located at the junction of forest parks and city parks, connecting urban and rural areas geographically, with intensive transportation networks. When citizens visit suburban parks for sightseeing and recreational activities, they must pass through transportation hubs. Therefore, whether residents are urban or rural, their most familiar and intuitive understanding of suburban parks is focused on nodes and boundaries. Citizens primarily identified elements such as subways, bus hubs, entrances, and exits. Thus, many citizens had a general image perception near the boundary of suburban parks. This feature was unique to suburban parks. This cognitive familiarity of citizens reflected the important role of nodes and boundaries when constructing the overall images of urban forests.
Urban parks are located in highly-urbanized areas, extending the many natural functions of forests to urban areas, and bringing socialized service functions and values to citizens. Citizens primarily focused on how urban parks were integrated with the overall urban development. Compared to forest parks and country parks, urban parks have the advantages of population, economy, society, and other resources. Their external landmarks are prominent and diverse, encompassing schools, hospitals, and government agencies, as well as other scenic spots of the city. Citizens have the highest perception of paths in these parks, because of the highly dense urban road network. Citizens and urban roads had the highest frequently of contact, with highly familiar perceptions. Finally, although the citizens were familiar with the nodes of urban parks, their familiarity is still lower than that of the corresponding elements of suburban parks.