This chapter deals with two separate but closely related topics. The first involves questions regarding preferred routes, either traversing physical (transport) networks or by directly connecting pre-defined locations. The second topic covered involves the selection of locations and ‘service areas’ (principally within existing networks) that meet pre-specified criteria. Many GIS packages provide a limited set of functions designed to answer basic questions of this kind. Some packages provide more extensive tools using optional add-ins, such as ESRI’s ArcGIS Network Analyst (now included in ArcGIS as standard), ESRI’s ArcGIS for Transportation Analytics option and Manifold’s Business Tools option. Other packages, such as Caliper’s TransCAD (built using the Maptitude GIS platform) and Citilab’s Cube suite (built using ArcGIS libraries), aim to provide a fully integrated GIS-T (GIS for Transportation) suite with an extensive range of routing and modeling facilities. As an illustration, TransCAD provides facilities for: network analysis (shortest paths, traveling salesman problems and network partitioning); transit analysis (designing and modeling the use of public transit networks and associated fare structures); transportation planning and travel demand modeling (trip modeling, modal split modeling and traffic assignment); vehicle routing and logistics (dispatching/collection problems, arc routing problems and flow-related problems); and territory management and site location modeling.