Citysurf is a server based 3D GIS software, developed by PiriReis. Citysurf is a new model for serving maps and interacting with the end user and  has been created to model and serve raster data at high speed and low bandwidth. Databases such as high resolution satellite images and aerial images are combined with digital terrain models and vector-based geographical information. Citysurf can serve data over local networks or the internet. Each end user can manage and analyse geographical data through the Citysurf Globe interface with advanced authorization system incorporated in CitySurf.