[postgis-devel] PointM, PolyLineM, PolygonM, ...
strk at refractions.net
strk at refractions.net
Mon Sep 20 09:28:56 PDT 2004
This is a continuation of an old thread about support
for Measured geometries (as supported by shapefiles).
See:
http://postgis.refractions.net/pipermail/postgis-users/2003-February/002149.html
For any type shapefile format supports 3 version:
Type - x,y
TypeM - x,y,m
TypeZ - x,y,z,m
Current (hwgeom/lwgeom) loader (shp2pgsql) makes these conversions:
Type -> geometry2d
TypeM -> geometry2d (you loose M!)
TypeZ -> geometry3d (you loose M!)
Current (hwgeom/lwgeom) dumper (pgsql2shp) makes these conversions:
geometry2d -> Type
geometry3d -> TypeZ (you waste space for empty M values !)
Now that postgis supports up to 4 dimensions geometry, what do you
think should be done ? My vision is this:
Type <-> geometry2d
TypeM <-> geometry3d
TypeZ <-> geometry4d
What do you think ?
--strk;
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