[geos-devel] MakeValid and empty collection component

[Even Rouault]

On mercredi 9 décembre 2020 12:13:17 CET Sandro Santilli wrote:
> I found out that GEOSMakeValid will remove EMPTY components from
> collections. The PostGIS implementation of it does not do this.
> 
> The rationale was that a collection with EMPTY component is NOT
> invalid as per OGC specification, so why removing them ? Isn't
> that a job for CollectionHomogenize or similar ?

Actually the unit tests have checks for this.

See tests/xmltester/tests/misc/makevalid.xml

<case>
    <desc>makevalid/geometry_collection</desc>
  <a>GEOMETRYCOLLECTION(POINT EMPTY,LINESTRING EMPTY,POLYGON((0 0,0 1,1 1,1 
0,0 0),(0 0.5,0.5 0.1,1 0.5,0 0.5)))</a>
  <test>
    <op name="makevalid" arg1="a">
        GEOMETRYCOLLECTION (MULTIPOLYGON (((0.0 0.0, 0.0 0.5, 0.5 0.1, 1.0 
0.5, 1.0 0.0, 0.0 0.0)), ((0.0 0.5, 0.0 1.0, 1.0 1.0, 1.0 0.5, 0.0 
0.5))),LINESTRING EMPTY, POINT EMPTY)
    </op>
  </test>
</case>



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