convert a shapefile to kml using Gdal library in C#

Question

Hi I want to convert a shapefile (shp) to kml using Gdal library in C#. I write a code but the output is not in kml format.

Here is my code:

using OSGeo.OGR;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using OSGeo.OSR;
using OSGeo.GDAL;

namespace ConsoleApp1 {
    class Program {
        static void Main(string[] args) {
            GdalConfiguration.ConfigureGdal();
            GdalConfiguration.ConfigureOgr();
            convert();
        }
        public static void convert() {
            string shapeFilePath = @ "C:\riv1.shp";

            Ogr.RegisterAll();
            var drv = Ogr.GetDriverByName("ESRI Shapefile");

            var ds = drv.Open(shapeFilePath, 0);


            OSGeo.OGR.Layer layer = ds.GetLayerByIndex(0);

            OSGeo.OGR.Feature f;
            layer.ResetReading();

            System.Text.StringBuilder sb = new System.Text.StringBuilder();


            while ((f = layer.GetNextFeature()) != null) {
                var geom = f.GetGeometryRef();
                if (geom != null) {
                    var geometryKml = geom.ExportToKML("");
                    sb.AppendLine(geometryKml);
                }
            }

            var kmlStr = sb.ToString();
            System.IO.File.WriteAllText("c:/riv1.kml", kmlStr);

        }

    }
}

This convert work fine by FWTools Shell but I need to do it in my code. Please help me if you know what I miss.

Answer 1

You can use the CopyLayer() method to just copy the shapefile layer to a new Kml datasource.

        // load the shapefile in a datasoure
        Driver shpDriver = Ogr.GetDriverByName("ESRI Shapefile");
        DataSource shpDatasource = Ogr.Open(shapefilePath, 0);
        if (shpDatasource == null)
            return false;

        // load the shapefile layer
        Layer shpLayer = shpDatasource.GetLayerByIndex(0);

        // create the KML datasource layer
        Driver kmlDriver = Ogr.GetDriverByName("KML");
        DataSource KmlDatasource = Ogr.Open(KmlPath, 0);            
        KmlDatasource = kmlDriver.CreateDataSource(KmlPath, new string[] {});

        // copy the shapefile layer
        Layer newLayer = KmlDatasource.CopyLayer(shpLayer, shpLayer.GetName(), new string[] { });

Answer 2

Thank you very much Maxwell77. I just ran it and add tiny modification to let it work correctly.

GdalConfiguration.ConfigureGdal();
GdalConfiguration.ConfigureOgr();
OSGeo.OGR.Ogr.RegisterAll();
Driver drv = Ogr.GetDriverByName("ESRI Shapefile");
DataSource shpDatasource = Ogr.Open(shapefilePath, 0);
if (shpDatasource == null)
  return false;

// load the shapefile layer
Layer shpLayer = shpDatasource.GetLayerByIndex(0);

// create the KML datasource layer
using (Driver kmlDriver = Ogr.GetDriverByName("KML"))
{
  // DataSource KmlDatasource = Ogr.Open(KmlPath, 0);
  using (DataSource KmlDatasource = kmlDriver.CreateDataSource(KmlPath, new string[] { }))
  {
    // copy the shapefile layer
    Layer newLayer = KmlDatasource.CopyLayer(shpLayer, shpLayer.GetName(), new string[] {  });
    newLayer.Dispose();
  }

}
}