Isochrones are an important tool for carrying out reachability analyses. In Multimodal Spatial Networks they are hard to compute, since multiple modalities and schedules of the public transportation systems need to be considered. Throughout this thesis new algorithms to compute isochrones in such networks are developed. Those include loading parts of the data source with the help of so called tile regions as well as computations on previously calculated results. The application capabilities of isochrones are extended by defining averaged and time-invariant isochrones. By introducing elevation aware isochrone computation the accuracy of the results is further increased. An approach that is able to tailor isochrones to individual users is presented as well.
One of the major problems in the field of isochrone computation is the acquisition of the necessary data. To address the lack of datasets on which such calculations can be performed, a generalized dataset creation is introduced that allows not only to create real-world models, but also to include information from external data sources. Data is merged with information about the public transportation system and with Digital Elevation Models that include elevation data. To ease the visualization of computed isochrones in real-world datasets a web-application called "IsoMap" is presented. It can be used to vary computation parameters and for basic analyses within the results.