Introduction to PostGIS
36. Appendix B: Glossary¶
- A “coordinate reference system”. The combination of a geographic coordinate system and a projected coordinate system.
- Geospatial Data Abstraction Library, pronounced “GOO-duhl”, an open source raster access library with support for a large number of formats, used widely in both open source and proprietary software.
- Geographic information system or geographical information system captures, stores, analyzes, manages, and presents data that is linked to location.
- Geography Markup Language. GML is the OGC standard XML format for representing spatial feature information.
- “JavaServer Page Template Library”, a tag library for JSP that encapsulates many of the standard functions handled in JSP (database queries, iteration, conditionals) into a terse syntax.
- “JavaServer Pages” a scripting system for Java server applications that allows the interleaving of markup and Java procedural code.
- “Keyhole Markup Language”, the spatial XML format used by Google Earth. Google Earth was originally written by a company named “Keyhole”, hence the (now obscure) reference in the name.
- The Open Geospatial Consortium (OGC) is a standards organization that develops specifications for geospatial services.
- The Open Source Geospatial Foundation (OSGeo) is a non-profit foundation dedicated to the promotion and support of open source geospatial software.
- The Simple Features for SQL (SFSQL) specification from the OGC defines the types and functions that make up a standard spatial database.
- The Styled Layer Descriptor (SLD) specification from the OGC defines an format for describing cartographic rendering of vector features.
- “Spatial reference ID” a unique number assigned to a particular “coordinate reference system”. The PostGIS table spatial_ref_sys contains a large collection of well-known srid values and text representations of the coordinate reference systems.
- “Structured query language” is the standard means for querying relational databases.
- SQL Multimedia; includes several sections on extended types, including a substantial section on spatial types.
- “Scalable vector graphics” is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic (i.e. interactive or animated).
- The Web Feature Service (WFS) specification from the OGC defines an interface for reading and writing geographic features across the web.
- The Web Map Service (WMS) specification from the OGC defines an interface for requesting rendered map images across the web.
- “Well-known binary”. Refers to the binary representation of geometries described in the Simple Features for SQL specification (SFSQL).
- “Well-known text”. Can refer either to the text representation of geometries, with strings starting “POINT”, “LINESTRING”, “POLYGON”, etc. Or can refer to the text representation of a CRS, with strings starting “PROJCS”, “GEOGCS”, etc. Well-known text representations are OGC standards, but do not have their own specification documents. The first descriptions of WKT (for geometries and for CRS) appeared in the SFSQL 1.0 specification.
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