| Value | Meaning |
|---|---|
| wkbVariantOldOgc | < Old-style 99-402 extended dimension (Z) WKB types |
| wkbVariantIso | < SFSQL 1.2 and ISO SQL/MM Part 3 extended dimension (Z&M) WKB types |
| wkbVariantPostGIS1 | < PostGIS 1.X has different codes for CurvePolygon, MultiCurve and MultiSurface |
Output variants of WKB we support.
99-402 was a short-lived extension to SFSQL 1.1 that used a high-bit flag to indicate the presence of Z coordinates in a WKB geometry.
SQL/MM Part 3 and SFSQL 1.2 use offsets of 1000 (Z), 2000 (M) and 3000 (ZM) to indicate the present of higher dimensional coordinates in a WKB geometry. Reference: <a href="https://portal.opengeospatial.org/files/?artifact_id=320243"> 09-009_Committee_Draft_ISOIEC_CD_13249-3_SQLMM_Spatial.pdf</a>, ISO/IEC JTC 1/SC 32 N 1820, ISO/IEC CD 13249-3:201x(E), Date: 2009-01-16. The codes are also found in §8.2.3 of <a href="http://portal.opengeospatial.org/files/?artifact_id=25355"> OGC 06-103r4 "OpenGIS® Implementation Standard for Geographic information - Simple feature access - Part 1: Common architecture", v1.2.1</a>