Monitoring and protecting the environment is a cross-cutting task. Conventional monothematic information systems without spatial reference usually fail, since it is important to link a multitude of technical data on the environment with each other. It is only through this linkage that new and more meaningful information on the complex environmental system can be created. Most planning measures can be supported very versatilely by the integration into a GIS with its database. This ranges from the legal side (real estate cadastre) via the planning process (urban and landscape planning) to the environmental aspect (environmental impact assessment (EIA)). Investigations of spatially effective planning, ecological holistic planning with their assessments of the impairment risk for individual factors of the ecosystem can only be realised by linking all existing data. A GIS is ideally suited for the administration, provision, analysis and visualisation of data. In addition, the so-called environmental monitoring also belongs to this task, i.e. the monitoring of the environment and the factors affecting it such as traffic, agriculture, industry etc. by means of remote sensing methods or geosensor networks. Models for monitoring noise and pollutant propagation (flow and propagation models) use measurement data as well as data processed in GIS to parameterise terrain heights, the vegetation situation or the building structure. Appropriate spatiotemporal models also allow simulations (e.g. flood scenarios, pollutant dispersal, noise mapping) to support disaster management or the estimation of the effects of different planning variants.
The development of environmental information systems has as its main objectives environmental monitoring, support for environmental precautions, restoration of environmental damage and response to environmental accidents. All these tasks require spatial data as a basis for documentation and decision-making. Applications of UIS therefore range from the recording of radioactivity or the mapping of biotopes and species diversity to the derivation of noise pollution and water quality. UIS are developed at the international, federal, state and municipal levels as well as in private companies (Enterprises EIS). At the municipal level, for example, the environmental topics to be dealt with range from green areas, trees, cemeteries, biotopes, soil and contaminated sites to wells, groundwater and water cadastres.