[geos-devel] Problems creating polygons with holes
strk
strk at keybit.net
Mon Jun 28 16:59:24 EDT 2004
On Mon, Jun 28, 2004 at 01:50:09PM -0700, Martin Davis wrote:
> Strk:
>
> IMO the current paradigm (that of constructors taking ownership of their
> components) is the correct one. The reason is to avoid unecessary
> copying of argument data (which could be large). It should be left up
> to the caller to decide when and where they need to copy arguments.
>
> Yes, this is a potential source of errors for clients, if they don't
> understand how to properly use the library. But the alternative forces
> clients to tolerate extra overhead even when they don't need it, which
> is not friendly behaviour from a library.
>
> If this is really onerous, two versions of each constructor could be
> provided. Or possibly even better, a pattern & support class to make it
> easy to copy arguments.
Unfortunately geos-1.0 was released with mixed policy, which is what
I'm trying to conform now.
I like the idea of letting callers specify whether or not to take
ownership and so far duplicationg each constructor seems the cleaner
way (adding a parameter takeOwnership would make all const correctness
useless and will require modifications in many places).
What do you mean by pattern & support class ?
--strk;
>
> Martin Davis, Senior Technical Architect
> Vivid Solutions Inc. www.vividsolutions.com
> Suite #1A-2328 Government Street Victoria, B.C. V8T 5G5
> Phone: (250) 385 6040 - Local 308 Fax: (250) 385 6046
>
>
> > -----Original Message-----
> > From: strk [mailto:strk at keybit.net]
> > Sent: June 28, 2004 12:59 PM
> > To: Darren Carman
> > Cc: GEOS Development List
> > Subject: Re: [geos-devel] Problems creating polygons with holes
> >
> >
> > I could not find the problem.
> > Here is a reduced code exploiting the error.
> > I'll keep inspecting this...
> >
> > BTW: I don't feel comportable in Polygon constructor taking
> > ownership of passed arguments, what people think about
> > modifying this as well ?
> >
> > --strk;
> >
> > //--------------------------8<-------------------
> >
> > #include <geos/io.h>
> > #include <geos/geom.h>
> > #include <geos/util.h>
> >
> > using namespace std;
> > using namespace geos;
> >
> > int main(int argc, char *argv[]) {
> > Coordinate c;
> > CoordinateList *cl1 =
> > CoordinateListFactory::internalFactory->createCoordinateList();
> > CoordinateList *cl2 =
> > CoordinateListFactory::internalFactory->createCoordinateList();
> >
> > c.x = 339252; c.y = 1019302; cl1->add(c);
> > c.x = 339252; c.y = 1029077; cl1->add(c);
> > c.x = 348752; c.y = 1029077; cl1->add(c);
> > c.x = 346102; c.y = 1019653; cl1->add(c);
> > c.x = 339252; c.y = 1019302; cl1->add(c);
> >
> > c.x = 340000; c.y = 1020000; cl2->add(c);
> > c.x = 340000; c.y = 1021000; cl2->add(c);
> > c.x = 341000; c.y = 1021000; cl2->add(c);
> > c.x = 341000; c.y = 1020000; cl2->add(c);
> > c.x = 340000; c.y = 1020000; cl2->add(c);
> >
> > try {
> > GeometryFactory *gf=new GeometryFactory(new
> > PrecisionModel(),0);
> >
> > Geometry
> > *geom1=gf->createPolygon(gf->createLinearRing(cl1),NULL);
> > cout<<"geom1: "<<geom1->toString()<<endl;
> > Geometry
> > *geom2=gf->createPolygon(gf->createLinearRing(cl2),NULL);
> > cout<<"geom2: "<<geom2->toString()<<endl;
> > vector<Geometry*>*holes = new vector<Geometry*>(1);
> > (*holes)[0] = geom2->clone();
> > Geometry
> > *geom3=gf->createPolygon(gf->createLinearRing(cl1),holes);
> > cout<<"geom3: "<<geom3->toString()<<endl;
> > delete cl1;
> > delete cl2;
> > } catch (GEOSException *ge) {
> > cout << "ERROR: " << ge->toString() << endl;
> > } catch (...) {
> > cout << "generic ERROR" << endl;
> > }
> > }
> >
> > //--------------------------8<-------------------
> >
> >
> > On Mon, Jun 28, 2004 at 11:47:17AM +0100, Darren Carman wrote:
> > > #include <geos/io.h>
> > > #include <geos/geom.h>
> > >
> > > using namespace std;
> > > using namespace geos;
> > >
> > > typedef struct boundaryPt {
> > > double x;
> > > double y;
> > > };
> > > typedef vector<boundaryPt> boundary;
> > > typedef vector<boundary> boundaryList;
> > > typedef vector<boundaryList> polygonList;
> > >
> > > polygonList ptPolygons;
> > >
> > > int main(int argc, char *argv[]) {
> > > vector<Geometry *> polygons;
> > > vector<Geometry *> holes;
> > > int i,j,k;
> > > string resStr = "";
> > >
> > > boundaryPt poly1[5];
> > > boundaryPt hole1[5];
> > > boundary tmpBoundary;
> > > boundaryList tmpBoundaryList;
> > > polygonList ptPolygons;
> > >
> > > poly1[0].x = 339252;
> > > poly1[0].y = 1019302;
> > > poly1[1].x = 339252;
> > > poly1[1].y = 1029077;
> > > poly1[2].x = 348752;
> > > poly1[2].y = 1029077;
> > > poly1[3].x = 346102;
> > > poly1[3].y = 1019653;
> > > poly1[4].x = 339252;
> > > poly1[4].y = 1019302;
> > >
> > > hole1[0].x = 340000;
> > > hole1[0].y = 1020000;
> > > hole1[1].x = 340000;
> > > hole1[1].y = 1021000;
> > > hole1[2].x = 341000;
> > > hole1[2].y = 1021000;
> > > hole1[3].x = 341000;
> > > hole1[3].y = 1020000;
> > > hole1[4].x = 340000;
> > > hole1[4].y = 1020000;
> > >
> > > for (i=0; i<5; i++) {
> > > tmpBoundary.push_back(poly1[i]);
> > > }
> > > tmpBoundaryList.push_back(tmpBoundary);
> > > tmpBoundary.clear();
> > >
> > > for (i=0; i<5; i++) {
> > > tmpBoundary.push_back(hole1[i]);
> > > }
> > > tmpBoundaryList.push_back(tmpBoundary);
> > > tmpBoundary.clear();
> > >
> > > ptPolygons.push_back(tmpBoundaryList);
> > > for(int i=0; i< static_cast<int>(tmpBoundaryList.size()); i++) {
> > > tmpBoundaryList[i].clear();
> > > }
> > > tmpBoundaryList.clear();
> > >
> > >
> > > try{
> > > GeometryFactory *gf=new GeometryFactory(new PrecisionModel(),0);
> > >
> > > // for each outer ring create a CoordinateList and add
> > all the points to it
> > > for(i=0; i< static_cast<int>(ptPolygons.size()); i++) {
> > > CoordinateList
> > *cl1=CoordinateListFactory::internalFactory->createCoordinateList();
> > > boundaryList bl = ptPolygons[i];
> > > boundary b = bl[0];
> > > cout << "Polygon " << i << endl;
> > > for(k=0; k< static_cast<int>(b.size()); k++) {
> > > cout << "Added point " << b[k].x << ',' << b[k].y << endl;
> > > cl1->add(*(new Coordinate(b[k].x,b[k].y)));
> > > }
> > >
> > > // for each hole create a coordinate list like above,
> > create a polygon and add to a Geometry vector
> > > for(j=1; j< static_cast<int>(bl.size()); j++) {
> > > cout << "Hole " << j << endl;
> > > boundary b = bl[j];
> > > CoordinateList
> > *cl2=CoordinateListFactory::internalFactory->createCoordinateList();
> > > for(k=0; k< static_cast<int>(b.size()); k++) {
> > > cout << "Added point " << b[k].x << ',' << b[k].y << endl;
> > > cl2->add(*(new Coordinate(b[k].x,b[k].y)));
> > > }
> > > cout << "Creating polygon for hole " << j << ": "
> > << cl2->toString() << endl;
> > > Geometry
> > *geom1=gf->createPolygon(gf->createLinearRing(cl2),NULL);
> > > cout << "Geometry " << j << " : " <<
> > geom1->toString() << endl;
> > > holes.push_back(geom1);
> > > delete cl2;
> > > }
> > > // create a polygon from the 1st CoordinateList and the holes
> > > cout << "Creating polygon " << i << ": " <<
> > cl1->toString() << endl;
> > > Geometry
> > *geom2=gf->createPolygon(gf->createLinearRing(cl1),&holes);
> >
> > > cout << "test " << endl;
> > > cout << "Geometry " << i << " : " <<
> > geom2->toString() << endl;
> > >
> > > // save this polygon in another vector
> > > cout << "Adding polygon " << i << endl;
> > > polygons.push_back(geom2);
> > > delete cl1;
> > > }
> > > cout << "Creating multi-polygon" << endl;
> > > // when all done create a MultiPolygon object
> > > Geometry *geom3=gf->createMultiPolygon(&polygons);
> > > cout << "Creating string" << endl;
> > > resStr = geom3->toString();
> > >
> > > //clean up
> > > delete geom3;
> > > delete gf;
> > > }
> > > catch (GEOSException *ge) {
> > > cout << "ERROR: " << ge->toString() << endl;
> > > }
> > > cout << resStr << endl;
> > > }
> > >
> > > -----Original Message-----
> > > From: strk [mailto:strk at keybit.net]
> > > Sent: 28 June 2004 11:28
> > > To: GEOS Development List
> > > Subject: Re: [geos-devel] Problems creating polygons with holes
> > >
> > >
> > > Can you produce a neter code exploiting the bug ?
> > > I mean a .cpp file I can compile and run and debug :)
> > >
> > > -strk;
> > >
> > > On Mon, Jun 28, 2004 at 11:05:22AM +0100, Darren Carman wrote:
> > > > defs:
> > > > typedef struct boundaryPt {
> > > > double x;
> > > > double y;
> > > > };
> > > > typedef vector<boundaryPt> boundary;
> > > > typedef vector<boundary> boundaryList;
> > > > typedef vector<boundaryList> polygonList;
> > > >
> > > > class members used:
> > > > polygonList ptPolygons;
> > > > string tmpStr;
> > > > string errMsg;
> > > >
> > > > class function:
> > > > string c_polygon_gml::WKTString(void) {
> > > > TRACE_FUNC("c_polygon_gml::WKTString");
> > > > vector<Geometry *> polygons;
> > > > vector<Geometry *> holes;
> > > > int i,j,k;
> > > > string resStr = "";
> > > >
> > > > try{
> > > > GeometryFactory *gf=new GeometryFactory(new
> > PrecisionModel(),0);
> > > >
> > > > // for each outer ring create a CoordinateList and
> > add all the points to it
> > > > for(i=0; i< static_cast<int>(ptPolygons.size()); i++) {
> > > > CoordinateList
> > *cl1=CoordinateListFactory::internalFactory->createCoordinateList();
> > > > boundaryList bl = ptPolygons[i];
> > > > boundary b = bl[0];
> > > > TRACE_OUTPUT("Polygon " << i);
> > > > for(k=0; k< static_cast<int>(b.size()); k++) {
> > > > TRACE_OUTPUT("Added point " << b[k].x << ',' << b[k].y);
> > > > cl1->add(*(new Coordinate(b[k].x,b[k].y)));
> > > > }
> > > >
> > > > // for each hole create a coordinate list like
> > above, create a polygon and add to a Geometry vector
> > > > for(j=1; j< static_cast<int>(bl.size()); j++) {
> > > > TRACE_OUTPUT("Hole " << j);
> > > > boundary b = bl[j];
> > > > CoordinateList
> > *cl2=CoordinateListFactory::internalFactory->createCoordinateList();
> > > > for(k=0; k< static_cast<int>(b.size()); k++) {
> > > > TRACE_OUTPUT("Added point " << b[k].x << ',' << b[k].y);
> > > > cl2->add(*(new Coordinate(b[k].x,b[k].y)));
> > > > }
> > > > TRACE_OUTPUT("Creating polygon for hole " << j <<
> > ": " << cl2->toString());
> > > > Geometry
> > *geom1=gf->createPolygon(gf->createLinearRing(cl2),NULL);
> > > > TRACE_OUTPUT("Geometry " << j << " : " <<
> > geom1->toString());
> > > > holes.push_back(geom1);
> > > > delete cl2;
> > > > }
> > > > // create a polygon from the 1st CoordinateList and
> > the holes
> > > > TRACE_OUTPUT("Creating polygon " << i << ": " <<
> > cl1->toString());
> > > > Geometry
> > *geom2=gf->createPolygon(gf->createLinearRing(cl1),&holes);
> > > > TRACE_OUTPUT("test ");
> > > > TRACE_OUTPUT("Geometry " << i << " : " <<
> > geom2->toString());
> > > >
> > > > // save this polygon in another vector
> > > > TRACE_OUTPUT("Adding polygon " << i);
> > > > polygons.push_back(geom2);
> > > > delete cl1;
> > > > }
> > > > TRACE_OUTPUT("Creating multi-polygon");
> > > > // when all done create a MultiPolygon object
> > > > Geometry *geom3=gf->createMultiPolygon(&polygons);
> > > > TRACE_OUTPUT("Creating string");
> > > > resStr = geom3->toString();
> > > >
> > > > //clean up
> > > > delete geom3;
> > > > delete gf;
> > > > }
> > > > catch (GEOSException *ge) {
> > > > errMsg = ge->toString();
> > > > }
> > > > return resStr;
> > > > }
> > > >
> > > > XML read in by class and stored in ptPolygons:
> > > > <?xml version="1.0" encoding="UTF-8"?>
> > > > <AreaDefinition>
> > > > <GDSRequest>
> > > > <query>
> > > > <AreaQuery outputContent="public">
> > > > <queryArea>
> > > > <Polygon srsName="osgb:BNG">
> > > > <outerBoundaryIs>
> > > > <LinearRing>
> > > > <coordinates>
> > > > 339252,1019302
> > > > 339252,1029077
> > > > 348752,1029077
> > > > 346102,1019653
> > > > 339252,1019302
> > > > </coordinates>
> > > > </LinearRing>
> > > > </outerBoundaryIs>
> > > > <innerBoundaryIs>
> > > > <LinearRing>
> > > > <coordinates>
> > > > 340000,1020000
> > > > 340000,1021000
> > > > 341000,1021000
> > > > 341000,1020000
> > > > 340000,1020000
> > > > </coordinates>
> > > > </LinearRing>
> > > > </innerBoundaryIs>
> > > > </Polygon>
> > > > </queryArea>
> > > > </AreaQuery>
> > > > </query>
> > > > </GDSRequest>
> > > > </AreaDefinition>
> > > >
> > > > Output:
> > > > TR: TRACE ENTRY:c_polygon_gml::WKTString line 168 file
> > c_polygon_gml.cpp
> > > > TR: Polygon 0
> > > > TR: Added point 339252,1.0193e+06
> > > > TR: Added point 339252,1.02908e+06
> > > > TR: Added point 348752,1.02908e+06
> > > > TR: Added point 346102,1.01965e+06
> > > > TR: Added point 339252,1.0193e+06
> > > > TR: Hole 1
> > > > TR: Added point 340000,1.02e+06
> > > > TR: Added point 340000,1.021e+06
> > > > TR: Added point 341000,1.021e+06
> > > > TR: Added point 341000,1.02e+06
> > > > TR: Added point 340000,1.02e+06
> > > > TR: Creating polygon for hole 1:
> > (340000,1.02e+06,1.7e-308) (340000,1.021e+06,1.7e-308)
> > (341000,1.021e+06,1.7e-308) (341000,1.02e+06,1.7e-308)
> > (340000,1.02e+06,1.7e-308)
> > > > TR: Geometry 1 : POLYGON ((340000.0000000000000000
> > 1020000.0000000000000000, 340000.0000000000000000
> > 1021000.0000000000000000, 341000.0000000000000000
> > 1021000.0000000000000000, 341000.0000000000000000
> > 1020000.0000000000000000, 340000.0000000000000000
> > 1020000.0000000000000000))
> > > > TR: Creating polygon 0: (339252,1.0193e+06,1.7e-308)
> > (339252,1.02908e+06,1.7e-308) (348752,1.02908e+06,1.7e-308)
> > (346102,1.01965e+06,1.7e-308) (339252,1.0193e+06,1.7e-308)
> > > > TR: test
> > > > Segmentation fault
> > > >
> > > > Output when the hole is removed:
> > > > TR: TRACE ENTRY:c_polygon_gml::WKTString line 168 file
> > c_polygon_gml.cpp
> > > > TR: Polygon 0
> > > > TR: Added point 339252,1.0193e+06
> > > > TR: Added point 339252,1.02908e+06
> > > > TR: Added point 348752,1.02908e+06
> > > > TR: Added point 346102,1.01965e+06
> > > > TR: Added point 339252,1.0193e+06
> > > > TR: Creating polygon 0: (339252,1.0193e+06,1.7e-308)
> > (339252,1.02908e+06,1.7e-308) (348752,1.02908e+06,1.7e-308)
> > (346102,1.01965e+06,1.7e-308) (339252,1.0193e+06,1.7e-308)
> > > > TR: test
> > > > TR: Geometry 0 : POLYGON ((339252.0000000000000000
> > 1019302.0000000000000000, 339252.0000000000000000
> > 1029077.0000000000000000, 348752.0000000000000000
> > 1029077.0000000000000000, 346102.0000000000000000
> > 1019653.0000000000000000, 339252.0000000000000000
> > 1019302.0000000000000000))
> > > > TR: Adding polygon 0
> > > > TR: Creating multi-polygon
> > > > TR: Creating string
> > > > TR: TRACE EXIT:c_polygon_gml::WKTString
> > > > ERROR:
> > > > WTF format
> > > > MULTIPOLYGON (((339252.0000000000000000 1019302.0000000000000000,
> > > > 339252.0000000000000000 1029077.0000000000000000,
> > > > 348752.0000000000000000 1029077.0000000000000000,
> > > > 346102.0000000000000000 1019653.0000000000000000,
> > > > 339252.0000000000000000 1019302.0000000000000000)))
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: strk [mailto:strk at keybit.net]
> > > > Sent: 28 June 2004 11:01
> > > > To: GEOS Development List
> > > > Subject: Re: [geos-devel] Problems creating polygons with holes
> > > >
> > > >
> > > > Can you send the test code ?
> > > > There are currently no known bug ...
> > > > --strk;
> > > >
> > > > On Mon, Jun 28, 2004 at 10:15:45AM +0100, Darren Carman wrote:
> > > > > Hi all,
> > > > >
> > > > > I am creating polygons with holes and want to use geos
> > to allow me
> > > > > to output them in WKT.
> > > > >
> > > > > A polygon without a hole works fine, but as soon as I
> > add a hole I
> > > > > get a segmentation fault after calling the
> > createPolygon function
> > > > > (GeometryFactory) and trying to run toString on that polygon.
> > > > >
> > > > > I am using version 1.0.
> > > > >
> > > > > I have tried getting the latest version from CVS but
> > this causes a
> > > > > segmentation fault to occur while adding the 5th polygon
> > > > > coordinate to the CoordinateList (there are only 4
> > coordinates in
> > > > > the test polygon, the 5th being the first one repeated
> > - I tried
> > > > > making it 6 to see if it was a problem with closing the polygon
> > > > > but I still got a segmentation fault while adding the 5th).
> > > > >
> > > > > Is there a fix for this, or has anyone come accross it?
> > > > >
> > > > > Thanks in advance,
> > > > > Darren
> > > > >
> > > > >
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