Against this background, an urban structure type mapping was carried out. The inner area of Bad Homburg was divided into 102 urban spaces and a profile was created for each urban space. As many urban areas are spatially separated from each other but very similar in structure, they were grouped into 26 urban structure types, each with a similar settlement and open space structure. These urban structure types were evaluated and a model was developed for each type.
Important criteria were the degree of sealing, which allows conclusions to be drawn about the microclimatic conditions, the existing vegetation and the possibility of perceiving and experiencing nature in the city. Birds were used as indicator species for the assessment. It was taken into account that bird species can make a significant contribution to the experience of nature in urban areas all year round.
Based on mapping of birds in representative areas in 2015, typical bird species were assigned to each type of urban structure. Three characteristic bird species are named for each structure type in the guiding principles. The consideration of the habitat requirements of these species in future measures thus corresponds to the guiding principles for the respective urban structure type. Where the bird species mentioned occur in relevant numbers of individuals or populations, a high-quality open space and settlement structure can be assumed.