tl;dr: Why is "3D-ness" variantly written "25D" and "Z", in wkbPoint* constants? Is this just a historical accident?
I just noticed ogrConstants for geometry types are not consistent. I have always thought of (logically) Point as a base type, with the option to add height, to add a measure field, or both. At first I thought this was POINTZ, POINTM and POINTZM (as ogrinfo prints it), with "3D" and "Measured" in the humanized description. I then found out that wkbPoint25D was what one needed to use in python, and didn't dig in, figuring that 2.5D was a 2D coordinate with a height as attribute vs a point in 3 dimensional space, as a subtle maybe-accurate maybe-off-base distinction, and I'd figure that out later. Today I wrote wkbPoint25DM and realized that was wrong and read the python code installed at /usr/pkg/lib/python3.13/site-packages/osgeo/ogr.py which refers to likely C constants of the same names wkbPoint = _ogr.wkbPoint wkbPointM = _ogr.wkbPointM wkbPointZM = _ogr.wkbPointZM wkbPoint25D = _ogr.wkbPoint25D But, a newer geometry type wkbMultiCurve = _ogr.wkbMultiCurve wkbMultiCurveZ = _ogr.wkbMultiCurveZ wkbMultiCurveM = _ogr.wkbMultiCurveM wkbMultiCurveZM = _ogr.wkbMultiCurveZM just uses Z. The WKT wikipedia article uses "3D" and "2.5D"/"25D" do not appear. Why are the (presumably original) types "25D" instead of Z? Is this meaningful, or just arbitrary naming? Sorry if I should have figured this out from reading docs - I did try. Really I'm asking if I'm failing to understand something I should understand. _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
