st_exteriorring on multisurface gives linestring

[mjurce]

Hi, by executing:

select st_astext(st_exteriorring( st_geometryN(st_geomfromText('MULTISURFACE( ( (701472.61 114358.807,701472.36 114358.807,701472.11 114358.807,701472.11 114359.307,701472.61 114359.307,701472.61 114358.807)))'),1)))

LINESTRING(701472.61 114358.807,701472.36 114358.807,701472.11 114358.807,701472.11 114359.307,701472.61 11 4359.307,701472.61 114358.807)

The result should be a COMPOUNDCURVE.

[pramsey]

Not sure I agree. The WKT BNF indicates that the rings of a CurvePolygon can be *any* of LineString, CircString or CompoundCurve.

<ring text> ::= 
    <linestring text body> | 
    <circularstring text representation> | 
    <compoundcurve text representation>

In this case, the multi-surface text you've defined has a LineString outer ring, why not return that?

[mjurce]

The CurvePolygon could have an exterior ring with arcs so returning always a compoundcurve is simpler because handle all the cases.