[gdal-dev] Create a shape file with polygons

[Jorge Martin]

Hello Frank,


I have made your change and it works, I can open the .shp with my GIS. Many
thanks for your help.

Best Regards,

Jorge

2011/1/18 Frank Warmerdam <warmerdam at pobox.com>

> On 11-01-18 11:28 AM, Jorge Martin wrote:
>
>> OGRPolygon myPoligon;
>>
>> tmp = strtok (Line, ":");
>>
>> szName = string (tmp);
>>
>>
>>        while (tmp != NULL)
>>            {
>>
>>        OGRLinearRing MyRing;// = (OGRLinearRing*)
>> OGRGeometryFactory::createGeometry(wkbLinearRing);
>>
>>         tmp = strtok (NULL, ",");
>>
>>         if(tmp)
>>         {
>>
>>                string Coords = string(tmp);
>>
>>               size_t pos = Coords.find(" ");
>>
>>               string CoordX = Coords.substr(0,pos);
>>               string CoordY = Coords.substr(pos);
>>
>>               x = atof(CoordX.c_str());
>>                y = atof(CoordY.c_str());
>>
>> MyRing.addPoint(x,y);
>>
>>
>>         }
>>
>>         myPoligon.addRing(&MyRing);
>>
>>     }
>>
>
> Jorge,
>
> The essence of your problem is that you are creating a new
> ring for each point instead of creating one ring for the
> polygon and adding all the points to that ring before adding
> the ring to the polygon.  A slightly altered form of the core
> that works looks like:
>
>        OGRPolygon myPoligon;
>        OGRLinearRing MyRing;// = (OGRLinearRing*)
>
>
>        tmp = strtok (Line, ":");
>        szName = string (tmp);
>        while (tmp != NULL)
>        {
>            OGRGeometryFactory::createGeometry(wkbLinearRing);
>
>            tmp = strtok (NULL, ",");
>
>            if(tmp)
>            {
>                string Coords = string(tmp);
>
>                size_t pos = Coords.find(" ");
>
>                string CoordX = Coords.substr(0,pos);
>                string CoordY = Coords.substr(pos);
>
>                x = atof(CoordX.c_str());
>                y = atof(CoordY.c_str());
>
>                MyRing.addPoint(x,y);
>            }
>        }
>
>        myPoligon.addRing(&MyRing);
>
> Best regards,
> --
>
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam,
> warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent
>
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