[Gdal-dev] Create Polygon in OGR / C#

[Jean Michel PIERRET]

Hi,

 

      I would like transform a geometry structure in a OGR.Geometry.

 

Struct MyGeometry

{

bool [] exterior = null;

int []  partStarts = null;

int []  partEnds = null;

 

double [] padfX = null;

double [] padfY = null;

}

 

When I use the method ExportToWkt and CreateFromWkt it's very slow.

Now I have this method for the transformation :

 

Geometry gm = null;

Geometry g = null;

Geometry lr = null;

 

g = new Geometry(wkbGeometryType.wkbPolygon);

 

for (int i = 0; i < partStarts.Length; i++)

{

      if (exterior[i])

      {

            if (i > 0)

            {

                  if (gm == null)

                        gm = new Geometry(wkbGeometryType.wkbMultiPolygon);

                  gm.AddGeometry(g);

                  g.Dispose();

                  g = null;

            }

 

            if (g == null)

                  g = new Geometry(wkbGeometryType.wkbPolygon);

      }

 

      lr = new Geometry(wkbGeometryType.wkbLinearRing);

      for (int j = partStarts[i]; j < partEnds[i]; j++)

            lr.AddPoint(padfX[j], padfY[j], 0);

 

      g.AddGeometry(lr);

      lr.Dispose();

      lr = null;

}

 

if (gm != null)

{

      if (g != null)

      {

            gm.AddGeometry(g);

            g.Dispose();

            g = null;

      }

 

      return gm;

}

else

      return g;

 

It works but it is not very quick, It's possible to have a function like in
the shapelib

 

SHPObject SHPCreateObject(ShapeType shpType, int nShapeId, int nParts, int[]
panPartStart, PartType[] paPartType, int nVertices, double[] adfX, double[]
adfY, double[] adfZ, double[] adfM);

 

Thanks for your support.

 

Best Regards.

 

 


 <mailto:jmp at geosys.com> Jean-michel PIERRET - Poste  376


Tel : +33 (0)5 62 47 80 76
Mail :  <mailto:jmp at geosys.com> jmp at geosys.com
GEOSYS SA

 

 

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