Simple Features

Simple Features are an OpenGIS standardwhich specifies digital storage of geographical data (point, line, polygon,multi-point, multi-line, etc) with both spatialand non-spatial attributes. Simple Features are based on 2D geometrywith linear interpolation between vertices. In general,a 2D geometry is simple if it contains no self-intersection.The OpenGIS Simple Features specificationsdefine various spatial operators, which can be used to generate newgeometries from existing geometries.

Types

Point

Example:POINT (10 10)

LineString

Example:LINESTRING( 10 10, 20 20, 30 40)

Polygon

Example:POLYGON ((10 10, 10 20, 20 20, 20 15, 10 10))

Multipoint

Example:MULTIPOINT(10 10, 20 20)

Multipolygon

Example:MULTIPOLYGON(((10 10, 10 20, 20 20, 20 15, 10 10)),((60 60, 70 70, 80 60, 60 60)))

GeomCollection

Example:GEOMETRYCOLLECTION(POINT (10 10), POINT(30 30), LINESTRING(15 15, 20 20))

External links

* [http://www.opengeospatial.org/specs/?page=specs OpenGIS Specifications (Standards)]
* [http://www.opengeospatial.org/standards/sfc OpenGIS Simple Features Specification for CORBA (99-054)]
* [http://www.opengeospatial.org/standards/sfo OpenGIS Simple Features Specification for OLE/COM (99-050)]
* [http://www.opengeospatial.org/standards/sfs OpenGIS Simple Features Specification for SQL (99-054, 05-134, 06-104r3)]
* [http://www.gdal.org/ogr/ OGR] - OGR library which implements relevant OGC standards
* [http://www.opengis.org/docs/99-049.pdf OpenGIS Simple Features Specifications For SQL]
* [http://dev.mysql.com/doc/refman/5.1/en/spatial-extensions.html MySQL 5.1 documentation on Spatial extensions]
* [http://postgis.refractions.net/ PostGIS Simple Features implementation for PostgreSQL]