Shapeless handling of WKB geometries.
Use approximate_wkb() to copy an approximate well-known binary representation of
a geometry. Along the way, reduce precision of double floating point coordinates
by replacing their three least-significant bytes with nulls. The resulting WKB
will match the original at up to 26 bits of precision, close enough for
spherical mercator zoom 18 street scale geography.
Reduced-precision WKB geometries will compress as much as 50% smaller with zlib.
|wkbGeometryCollection = 7|
wkbLineString = 2
wkbMultiLineString = 5
wkbMultiPoint = 4
wkbMultiPolygon = 6
wkbMultis = (4, 5, 6, 7)
wkbNDR = 1
wkbPoint = 1
wkbPolygon = 3
wkbXDR = 0