Anti-Grain Geometry A high quality graphics rendering engine that MapServer 5.0+ can use. It supports sub-pixel anti-aliasing, as well as many more features.
Wikipedia provides excellent coverage of CGI.
EPSG codes are numeric codes associated with coordinate system definitions. For instance, EPSG:4326 is geographic WGS84, and EPSG:32611 is "UTM zone 11 North, WGS84". The WMS protocol uses EPSG codes to describe coordinate systems. EPSG codes are published by the OGP Surveying and Positioning Committee. A list of PROJ definitions corresponding to the EPSG codes can be found in the file /usr/local/share/proj/epsg. PROJECTION describes how to use these in your Mapfile.
- Filter Encoding
GD is a graphics library for dynamic generation of images. It was the first graphics renderer that was available for MapServer, and was required by MapServer to operate.
GD support was removed in MapServer 7.0.
GDAL (Geospatial Data Abstraction Library) is a multi-format raster reading and writing library. It is used as the primary mechanism for reading raster data in MapServer. It is hosted at https://gdal.org/
Geometry Engine Open Source is a C/C++ port of the Java Topology Suite. It is used for geometric algebra operations like determining if a polygon is contained in another polygon or determining the resultant intersection of two or more polygons. MapServer optionally uses GEOS for geometric algebra operations.
- Map Scale
A treatise of mapping scale can be found on about.com.
Mapfile is the declarative language that MapServer uses to define data connections, map styling, templating, and server directives. Its format is xml-like and hierarchical, with closing END tags, but the format is not xml.
Wikipedia provides excellent coverage of the Mercator projection.
The Open Geospatial Consortium is a standards organization body in the GIS domain. MapServer supports numerous OGC standards.
OGR is the vector data access portion of the GDAL library. It provides access to a multitude of data formats.
OGR Vector Layers Through MapServer (Accessing OGR Layers through MapServer)
PROJ (formerly referred to as PROJ.4) is a library for projecting map data. It is used by MapServer and GDAL and a multitude of other Open Source GIS libraries.
A map projection is a mathematical transformation of the surface of a sphere (3D) onto a 2D plane. Due to the laws of the universe, each type of projection must make tradeoffs on how and what features it distorts.
A raster is a rectangular grid of pixels. Essentially an image. Rasters are supported in MapServer with a layer type of RASTER, and a variety of formats are supported including GeoTIFF, JPEG, and PNG.
Shapefiles are simple GIS vector files containing points, lines or areas. The format was designed and published by ESRI and is widely supported in the GIS world. It is effectively the native and highest performance format for MapServer.
- Spherical Mercator
Spherical Mercator (or more commonly known as the Google Mercator, or Web Mercator) is a term used to describe the default PROJECTION used by many commercial API providers for their resulting map tiles & services. The associated official EPSG code is EPSG:3857 (formerly "EPSG:900913").
Scalable Vector Graphics is an XML format that MapServer can output. It is frequently used in browser and mobile devices.
Shockwave Flash format that MapServer can generate for output.
A tileindex is a Shapefile or other Vector data source that contains footprints of Raster data coverage. MapServer can use a tileindex to render a directory of raster data. The tileindex allows MapServer to only read the data that intersects the requested map extent, rather than reading all of the data.
Geographic features described by geometries (point, line, polygon) on a (typically) cartesian plane.