Data Formats

　　The map server supports a variety of data in both raster image and vector formats. The vector data appear crisp and precise regardless of the resolution of the image and is ideal for representing such elements as cities and towns, roads and streets, populated areas and country boundaries.

　　Examples of vector data include US Census/Tiger data, which provides street-level detail for the entire continental United States, as well as NIMA's Digital Chart of the World (VMap0 / VPF) that provides country, shoreline, political boundary, population, transportation and industry, vegetation and other data for the entire world. Both datasets are available for use with the GLG Map Server.

　　The raster image data can greatly enhance the look and sophistication of a map image by providing vivid and colorful details to compliment the additional vector data (roads, etc.) overlaid on top of the image. One example of raster image data is a NASA Earth Image dataset, which is frequently used in various Earth images. The map server provides several special alpha-blending and transparency modes for overlaying semi-transparent weather maps on top of other raster and vector layers.

　　Elevation data is a special case of the raster image data which can be used to display elevation as color-coded thresholds or shaded relief image. It may also be used to query elevation of a particular point on the map.

Web-Server or Stand-Alone Library API Usage Mode

　　The GLG Map Server can operate both as a web-based GIS Map Server or stand-alone library API. In the stand-alone mode, the map server can be used as a C/C++ library  linked with a program: this mode may be used for applications installed on local machines that want to avoid using an Internet connection to receive map images. When linked with an application as a library, the map server does not require any connections to the outside world, providing a small and self-contained map generation module for real-time and embedded applications.