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KB10637 - Export resolution using DK GIS.ExportToImage function.

The default DK GIS.ExportToImage settings export to 1,000 x 1,000 pixels, regardless of the export image format. This can involve, therefore, pixel resampling and quality loss if the source imagery is of a higher resolution. So best is to set in the DK the export resolution, i.e., the number of exported pixels.

For no‚Äč reduction in image quality, specify in the DK to generate the export image at the same resolution as the source image layer. This involves determining the number of pixels in the source image. When exporting to a TatukGIS PixelStore image use, for example:

procedure TGISPixelStoreForm.BtnExportClick(Sender: TObject);
    width: integer;
    Layer: TGIS_LayerPixel;
    Layer := TGIS_LayerPixel(GIS.Items[0]);
    width := Round(( GIS.Extent.XMax - GIS.Extent.XMin ) / ( layer.Extent.XMax - layer.Extent.XMin) * layer.BitWidth);

    GIS.ExportToImage( path, GIS.Extent, width, 0);

In the case of multiple source image of different resolutions, it is important to specify which is the base source layer for determining the export resolution.

Also, set the GIS.BigExtentMargin to zero to correctly scale the resulting PixelStore image.

Created: September 14, 2005, Modified: September 18, 2015