[gdal-dev] Call for discussion on RFC 49: Curve geometries

Even Rouault even.rouault at spatialys.com
Wed Nov 5 07:01:58 PST 2014


This is a call for discussion on RFC 49: Curve geometries


Below the summary :
The current geometry model in GDAL 1.X makes use of points, lines, polygons 
and aggregations of them (multipoints, multilines, multipolygons and geometry 
collections). It was modeled from the geometry class hierarchy of the
"OpenGIS Simple Feature Access Part 1 : Common Architecture" (in its 1.1.0 

This RFC covers the addition of new geometry types that have been added in
ISO/IEC 13249 Part 3 Spatial (abreviated as ISO SQL/MM Part 3):
  * circular string: a circular arc, or a sequence of connected circular arcs,
    each of them describe by 3 points: the first point of the arc, an
    intermediate point and the final point
  * compound curve: a sequence of connected curves, either line strings or
    circular strings
  * curve polygon: polygon consisting of one outer ring, and zero or more
    inner ring. Each ring can be one of the curve implementations: line
    strings, circular strings, compound curves.
  * multicurve: a collection of curves (line strings, circular strings,
    compound curves)
  * multisurface: a collection of surfaces (polygons, curve polygons)

The scope of this RFC consists in :
  * adding the new geometry classes to the existing geometry class hierarchy,
    with the corresponding importer and exporter of WKT (Well Known Text) and
    WKB (Well Known Binary) encodings
  * adding methods to convert those curve geometries into their approximated
    linear version, and to do the reverse operation
  * upgrading some of the drivers that can support such geometries : GML (and
    indirectly NAS, WFS), PostGIS/PGDump, GeoPackage, SQLite, CSV, VRT.

Have a good reading,


Spatialys - Geospatial professional services

More information about the gdal-dev mailing list