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<TITLE>RE: [geos-devel] OverlayOp JTS port</TITLE>
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<P><FONT SIZE=2>I apologize for the barrage of questions. As far as I can tell the<BR>
OverlayOp.cpp is vintage JTS 1.7 (which I think is same as the JTS 1.9 for this class)<BR>
<BR>
except it has the additional calls of<BR>
<BR>
checkObviouslyWrongResult() - which most of that code looks like it would never<BR>
be called because of the #ifdefs except for the <BR>
<BR>
assert(resultGeom);<BR>
UNREFERENCED_PARAMETER(opCode); (have no clue what this does)<BR>
<BR>
and also a<BR>
elevationMatrix->elevate(resultGeom);<BR>
<BR>
which looks like will get called since USE_ELEVATION_MATRIX 1.<BR>
<BR>
Is the elevationMatrix designed to deal with 3d geometries? Didn't realize<BR>
Union actually works with those, but then I never tried it with 3d.<BR>
<BR>
So I'm a little puzzled why these 2 extra function calls since I always thought<BR>
GEOS was at best on par with JTS?<BR>
<BR>
Thanks,<BR>
Regina<BR>
<BR>
-----Original Message-----<BR>
From: geos-devel-bounces@lists.osgeo.org on behalf of Obe, Regina<BR>
Sent: Wed 9/17/2008 9:26 AM<BR>
To: GEOS Development List<BR>
Subject: [geos-devel] OverlayOp JTS port<BR>
<BR>
I'm looking at the operation.overlay.OverlayOp in geos trunk<BR>
<BR>
In the header it says<BR>
Last port: operation/overlay/OverlayOp.java rev. 1.23<BR>
<BR>
But I don't believe this to be right since when I compare the<BR>
computeOverlay methods<BR>
against 1.2 and 1.3 versions of JTS codebase, it has an additional<BR>
EdgeNodingValidator check which wasn't introduced until later versions<BR>
of JTS.<BR>
<BR>
So I'm wondering is the OverlayOp.cpp a mix of JTS versions or is the<BR>
comment above just plain wrong.<BR>
<BR>
It also has a checkObviouslyWrongResult() check at the end of<BR>
computerOverlay which I haven't figured out which version that was<BR>
introduced in JTS (its not in 1.2,1.3, or 1.9). Is this a GEOS specific<BR>
check that has no JTS equivalent?<BR>
<BR>
Thanks,<BR>
Regina<BR>
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