webmap-import: Don't crash when trying to insert a feature without geometry.

Cf. for instance

	$ ogrinfo ./LST.vbk_projekteringsomraden.shp -sql "SELECT * FROM \"LST.vbk_projekteringsomraden\" WHERE OMRID = '1452-V-008'"
        […]
	Layer name: LST.vbk_projekteringsomraden
	Geometry: Polygon
	Feature Count: 1
	Extent: (-907106.000000, 727.000000) - (914131.738200, 7573766.311200)
	Layer SRS WKT:
	PROJCRS["SWEREF99 TM",
        […]
	OGRFeature(LST.vbk_projekteringsomraden):2043
	  OMRID (String) = 1452-V-008
	  PROJNAMN (String) = Grimsås Äspås
	  ANTALVERK (Integer64) = 0
	  AntalejXY (Integer64) = (null)
	  CALPROD (Real) = 0.000000000000000
	  PBYGGSTART (String) = (null)
	  PDRIFT (String) = (null)
	  Andringsan (String) = (null)
	  UnderByggn (String) = (null)
	  ORGNAMN (String) = Kraftö AB
	  ORGNR (String) = 556708-7456
	  EJAKTUELL (String) = Yes
	  KOMNAMN (String) = Tranemo
	  LANSNAMN (String) = Västra Götalands l
	  EL_NAMN (String) = (null)
	  Raderat (String) = No
	  ArendeStat (String) = (null)

1 files changed, 25 insertions, 21 deletions

diff --git a/webmap-import b/webmap-import
index c1d07a3..37826cf 100755
--- a/webmap-import
+++ b/webmap-import
@@ -1133,27 +1133,31 @@ def importSource2(lyr_dst, path, args={}, basedir=None, extent=None):
         feature2.SetFromWithMap(feature, False, fieldMap)
 
         geom = feature2.GetGeometryRef()
-        if ct is not None and geom.Transform(ct) != ogr.OGRERR_NONE:
-            raise Exception('Could not apply coordinate transformation')
-
-        eGType = geom.GetGeometryType()
-        if eGType != eGType_dst and not dGeomIsUnknown:
-            # Promote to multi, cf. apps/ogr2ogr_lib.cpp:ConvertType()
-            eGType2 = eGType
-            if eGType == ogr.wkbTriangle or eGType == ogr.wkbTIN or eGType == ogr.wkbPolyhedralSurface:
-                eGType2 = ogr.wkbMultiPolygon
-            elif not ogr.GT_IsSubClassOf(eGType, ogr.wkbGeometryCollection):
-                eGType2 = ogr.GT_GetCollection(eGType)
-
-            eGType2 = ogr.GT_SetModifier(eGType2, eGType_dst_HasZ, eGType_dst_HasM)
-            if eGType2 == eGType_dst:
-                mismatch[eGType] = mismatch.get(eGType, 0) + 1
-                geom = ogr.ForceTo(geom, eGType_dst)
-                # TODO call MakeValid()?
-            else:
-                raise Exception(f'Conversion from {ogr.GeometryTypeToName(eGType)} '
-                    f'to {ogr.GeometryTypeToName(eGType_dst)} not implemented')
-            feature2.SetGeometryDirectly(geom)
+        if geom is None:
+            if eGType_dst != ogr.wkbNone:
+                logging.warning('Source feature #%d has no geometry, trying to transfer anyway', feature.GetFID())
+        else:
+            if ct is not None and geom.Transform(ct) != ogr.OGRERR_NONE:
+                raise Exception('Could not apply coordinate transformation')
+
+            eGType = geom.GetGeometryType()
+            if eGType != eGType_dst and not dGeomIsUnknown:
+                # Promote to multi, cf. apps/ogr2ogr_lib.cpp:ConvertType()
+                eGType2 = eGType
+                if eGType == ogr.wkbTriangle or eGType == ogr.wkbTIN or eGType == ogr.wkbPolyhedralSurface:
+                    eGType2 = ogr.wkbMultiPolygon
+                elif not ogr.GT_IsSubClassOf(eGType, ogr.wkbGeometryCollection):
+                    eGType2 = ogr.GT_GetCollection(eGType)
+
+                eGType2 = ogr.GT_SetModifier(eGType2, eGType_dst_HasZ, eGType_dst_HasM)
+                if eGType2 == eGType_dst:
+                    mismatch[eGType] = mismatch.get(eGType, 0) + 1
+                    geom = ogr.ForceTo(geom, eGType_dst)
+                    # TODO call MakeValid()?
+                else:
+                    raise Exception(f'Conversion from {ogr.GeometryTypeToName(eGType)} '
+                        f'to {ogr.GeometryTypeToName(eGType_dst)} not implemented')
+                feature2.SetGeometryDirectly(geom)
 
         if lyr_dst.CreateFeature(feature2) != ogr.OGRERR_NONE:
             raise Exception(f'Could not transfer source feature #{feature.GetFID()}')