private Collection <Feature> GetElevationByLine(LineShape line, int pointNumber)
        {
            Elevation.Elevation elevation = new Elevation.Elevation();
            elevation.ElevationFeatureSourcesInDecimalDegrees.Add(new SrtmElevationFeatureSource(sourceDir));
            elevation.Open();
            Collection <Feature> features = elevation.GetElevationByLine(line, DistanceUnit.Meter, pointNumber);

            elevation.Close();
            return(features);
        }