decode
[Geographical data formats, Shapefile format]

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Detailed Description

Functions
SHP_DLL bool	TeDecodeShape (SHPObject *psShape, TeMultiGeometry &geomestries, string &objectId)
	Decodify a ShapeObject into a TerraLib multigeometry set.
SHP_DLL void	TeSHPPointDecode (SHPObject *psShape, TePointSet &ps, string &objectId)
	Decodify a ShapeObject into a TerraLib point set.
SHP_DLL void	TeSHPPolygonDecode (SHPObject *psShape, TePolygonSet &pols, string &objectId)
	Decodify a ShapeObject into a TerraLib polygon set.
SHP_DLL void	TeSHPPolyLineDecode (SHPObject *psShape, TeLineSet &ls, string &objectId)
	Decodify a ShapeObject into a TerraLib line set.

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Function Documentation

SHP_DLL bool TeDecodeShape	(	SHPObject *	psShape,
		TeMultiGeometry &	geomestries,
		string &	objectId
	)

Parameters:

	psShape	pointer to a shapelib shape object
	geometries	TerraLib multi geometry set to receive the geometries
	objectId	TerraLib identifier to this object

Definition at line 1899 of file TeDriverSHPDBF.cpp.

References TeMultiGeometry::lines_, SHPObject::nSHPType, TeMultiGeometry::points_, TeMultiGeometry::polygons_, SHPT_ARC, SHPT_ARCZ, SHPT_MULTIPOINT, SHPT_MULTIPOINTZ, SHPT_POINT, SHPT_POINTZ, SHPT_POLYGON, SHPT_POLYGONZ, TeSHPPointDecode(), TeSHPPolygonDecode(), and TeSHPPolyLineDecode().

{
        int shpType = psShape->nSHPType;
        switch (shpType)
        {
                case SHPT_POLYGON:
                case SHPT_POLYGONZ:
                        TeSHPPolygonDecode(psShape,geomestries.polygons_,objectId);
                        return true;
                case SHPT_ARC:
                case SHPT_ARCZ:
                        TeSHPPolyLineDecode(psShape,geomestries.lines_,objectId);
                        return true;
                case SHPT_POINT:
                case SHPT_POINTZ:
                case SHPT_MULTIPOINT:
                case SHPT_MULTIPOINTZ:
                        TeSHPPointDecode(psShape,geomestries.points_,objectId);
                        return true;
        }
        return false;
}

SHP_DLL void TeSHPPointDecode	(	SHPObject *	psShape,
		TePointSet &	ps,
		string &	objectId
	)

Parameters:

	psShape	pointer to a shapelib shape object
	ps	TerraLib point set to receive the geometries
	objectId	TerraLib identifier to this object

Definition at line 1922 of file TeDriverSHPDBF.cpp.

References TeGeomComposite< T >::add(), SHPObject::nVertices, TePoint::objectId(), SHPObject::padfX, and SHPObject::padfY.

{
        int nv = psShape->nVertices;
        for (int i = 0; i<nv; i++)
        {
                TePoint point(psShape->padfX[i], psShape->padfY[i]);
                point.objectId(objid);
                points.add(point);
        }
}

SHP_DLL void TeSHPPolygonDecode	(	SHPObject *	psShape,
		TePolygonSet &	pols,
		string &	objectId
	)

Parameters:

	psShape	pointer to a shapelib shape object
	ps	TerraLib polygon set to receive the geometries
	objectId	TerraLib identifier to this object

Definition at line 1957 of file TeDriverSHPDBF.cpp.

References TeGeomComposite< T >::add(), TeAbstractTheme::box(), TeGeometry::box(), TeLine2D::isRing(), SHPObject::nParts, SHPObject::nVertices, TeGeomComposite< T >::objectId(), SHPObject::padfX, SHPObject::padfY, SHPObject::panPartStart, TeGeomComposite< T >::size(), TeBOUNDARY, TeCLOCKWISE, TeGeometryArea(), TeINSIDE, TeMAXFLOAT, TeOrientation(), TeOUTSIDE, TeRelation(), and TeWithinOrCoveredByOrEquals().

{
        int iPart = 0;
        vector<int> partStart;

        // Build an array whose components point to the starting point
        // of the rings that compose the polygon shape
        for ( iPart = 0; iPart < psShape->nParts; iPart++ )
                partStart.push_back ( psShape->panPartStart[iPart] );
        partStart.push_back ( psShape->nVertices ); // point to the end

        vector<TePolygon> pList;
        vector<TeLinearRing> holes;
        int j = 0;
        iPart = 0;
        while (j < psShape->nVertices)
        {
                TeLine2D line;
                iPart++;                                                // while it doesn�t reach the start of next part
                while ( j < partStart[iPart] )  // build a line from the coordinates
                {
                        TeCoord2D pt ( psShape->padfX[j], psShape->padfY[j] );
                        line.add ( pt );
                        j++;
                }                                                               
                if (!line.isRing())                             // force the closing of opened rings
                        line.add(line[0]);

                // decide if a ring is an outter ring or an inner ring based on its orientation
                TeLinearRing ring(line);
                short orient = TeOrientation(ring);
                if(orient == TeCLOCKWISE)       // outter ring: start a new polygon
                {
                        TePolygon p;
                        p.add(ring);
                        p.objectId(objid);
                        pList.push_back(p);
                }
                else    // COUNTERCLOCKWISE => inner ring: put on the list of holes
                        holes.push_back(ring);
        } // read all vertices


        // even though there are rings that are in counter clockwise orientation, 
        // there aren't any clockwise orientation rings to be possible parents of 
        // these inner rings. The decision here: treat all of them as outter rings...
        if (pList.empty() && !holes.empty())
        {
                for (unsigned int i=0; i<holes.size(); ++i)
                {
                        TePolygon p;
                        p.add(holes[i]);
                        p.objectId(objid);
                        polys.add(p);
                }
                return;
        }

        if (pList.size() == 1)  // shape has only one polygon that should
        {                                               // contain all the inner rings
                for(unsigned int i = 0; i < holes.size(); ++i)
                        pList[0].add(holes[i]);
        }
        else
        {       // shape has multiple outter ring and inner rings
                // we have to find a parent to each inner ring 
                for(unsigned int i = 0; i < holes.size(); ++i)
                {
                        vector<TePolygon> candidates;
                        TeLinearRing ring = holes[i];
                        
                        // step 1: consider as a inner ring parent candidate every polygon 
                        // that intercepts the ring MBR
                        unsigned int j = 0;
                        for(j = 0; j < pList.size(); ++j)
                        {
                                if(TeWithinOrCoveredByOrEquals(ring.box(), pList[j].box()))
                                        candidates.push_back(pList[j]);
                        }

                        // if there is only one candidate this is the parent
                        if(candidates.size() == 1)
                        {
                                candidates[0].add(ring);
                                continue;
                        }

                        // step 2: refine the candidates to parent: consider only those 
                        // that contains the ring (not just its MBR)
                        vector<TePolygon> newCandidates;
                        for(j = 0; j < candidates.size(); ++j)
                        {
                                short rel = TeBOUNDARY;
                                bool inside = false;

                                unsigned int nthVert = ring.size();
                                unsigned int iVert = 0u;

                                while(iVert < nthVert)
                                {
                                        rel = TeRelation(ring[iVert], candidates[j][0]);

                                        if(rel & TeINSIDE)
                                        {
                                                inside = true;
                                                newCandidates.push_back(candidates[j]);
                                                break;
                                        }
                                        else if(rel & TeOUTSIDE)
                                                break;
                                        ++iVert;
                                }

                                if(iVert == nthVert)    
                                        break;
                        }
                        
                        // sort the new candidates according to their areas
                        int idxMinArea = 0;
                        double minArea = TeMAXFLOAT;
                        for(j = 0; j < newCandidates.size(); ++j)
                        {
                                if(TeGeometryArea(newCandidates[j].box()) < minArea)
                                {
                                        idxMinArea = j;
                                        minArea = TeGeometryArea(newCandidates[j].box());
                                }
                        }
                        // choose as parent the candidate that has the smaller area
                        if (!newCandidates.empty())
                                newCandidates[idxMinArea].add(ring);
                }
        }

        // add polygons to the list passed as parameter
        vector<TePolygon>::iterator it = pList.begin();
        while (it != pList.end())
        {
                polys.add(*it);
                ++it;
        }
}

SHP_DLL void TeSHPPolyLineDecode	(	SHPObject *	psShape,
		TeLineSet &	ls,
		string &	objectId
	)

Parameters:

	psShape	pointer to a shapelib shape object
	ps	TerraLib line set to receive the geometries
	objectId	TerraLib identifier to this object

Definition at line 1934 of file TeDriverSHPDBF.cpp.

References TeGeomComposite< T >::add(), SHPObject::nParts, SHPObject::nVertices, TeLine2D::objectId(), SHPObject::padfX, SHPObject::padfY, and SHPObject::panPartStart.

{
        int iPart,j=0,nextStart=0; 
        for (iPart = 0; iPart < psShape->nParts; iPart++)
        {
                if (iPart == psShape->nParts-1)
                        nextStart = psShape->nVertices;
                else 
                        nextStart = psShape->panPartStart[iPart+1];

                TeLine2D line;
                while (j<nextStart)
                {
                        TeCoord2D pt ( psShape->padfX[j], psShape->padfY[j] );
                        line.add ( pt );
                        j++;
                }
                line.objectId (objid);  
                lines.add ( line );
        }
}

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