The article assumes that the effectiveness of spatial development of the city largely depends on the analysis and consideration of new properties of space. The phenomena of isomerism and invariance as integral properties of urban space, their connection with other dimensions are studied. The theoretical provisions of the phenomenon of invariance and isomerism for urban planning are comprehended, their essence in relation to the problems of centrism is revealed; the role of urban networks and the dynamism of space; tasks of placing new objects in the complex spatial structure of cities. Approaches to the study and consideration of these characteristics in the spatial organization and development of urban systems are substantiated.
The categorical-conceptual apparatus is specified. Invariants are quantities, ratios, and properties that do not change from the changes in the components associated with them. They determine the comfort of the environment, the availability of facilities, the effectiveness of solutions and other properties of the space. The phenomenon of invariance is revealed through the functional zoning of the territory, the concept of centrism and the center of cities, communication connectivity and configuration of the urban network, the location of new objects in urban space. These are the instrumental properties of urban space, which are concentrated around the human dimension and human needs. Isomers in urban planning are changes in the properties of urban space with a constant material structure and environment, which is usually associated with the position of a single element in the system. Understanding this phenomenon is important and effective for understanding the morphology and essence of urban systems.
The city is an integral dynamic supersystem, and the development of urban space takes place both according to planned decisions and according to the laws of «living» matter. Space interacts with processes (social, technological, informational, functional and economic); combines squares, streets, recreational environment (parks, gardens, squares), creating their own social values. The principles and requirements for the use of invariance and isomerism in architectural and urban activities are substantiated.
Invariants determine the proportions of the ratios of shapes and spaces, environmental friendliness, functionality, nodes and internal geometry of space. Isomeric properties of urban space form, as a rule, qualitative symbolic, aesthetic and historically significant urban elements. They: change the range of impressions for users due to changes in architectural and urban characteristics and interactions with the user; increase individual and collective personalization, as well as general identity; make the space safer for the population, provide continuity in their control; universalize the space, which allows to develop new activities and apply mixed functionalities; organize urban nodes as spaces with high connectivity to other urban nodes and zones. The requirements to the formation of urban space are substantiated: the correct definition of the proportional relations between closed and open space, shape and size; environmental friendliness; functional sufficiency; the internal geometry of space must be determined by man; nodal places as invariants should direct people to cross space in all directions - to guarantee visually expressive entrances, attractive visual landmarks, accessibility, convenience of being near them and in them; the label must meet the criteria of scale and traditional design. It is proved that the use of isomerization provisions and urban invariants can be effective for the recovery and effective development of the urban organism.
Entropy of the Land Parcel Mosaic as a Measure of the Degree of Urbanization
