what is "Extended WKT"?

[VladimirAlexiev]

Hi @BenzclyZhang what is the "Extended WKT" that you use?

Is it this?

https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry#Format_variations: "EWKT: A PostGIS-specific format that includes the spatial reference system identifier (SRID) and up to 4 ordinate values (XYZM).[4][5] It also supports circular curves, following elements named (but not fully defined) within the original WKT: CircularString, CompoundCurve, CurvePolygon and CompoundSurface.[6]

• [4] https://github.com/postgis/postgis/blob/2.1.0/doc/ZMSgeoms.txt
• [5] https://postgis.net/docs/ST_GeomFromEWKT.html : supports Polyhedral surfaces, Triangles and Triangulated Irregular Network Surfaces (TIN).
• [6] https://postgis.net/docs/manual-1.4/ch04.html

Where is the authoritative documentation of this EWKT format?

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Can you point me to code that:

• does the conversion (by using IfcOpenShell-BIMserver-plugin).
• implements geometric functions and magic predicates? I browsed a bit but can only see classes that declare functions (so they are invokable from SPARQL), not the implementations

Thanks for any help!!