This article will walk you through how to convert DWG/DXF to KML using Global Mapper.
- Global Mapper on your computer.
Don't have it? You can follow these instructions to do it with GQIS which is free, or purchase Global Mapper from their website.
1. Launch Global Mapper.
2. Import DXF/DWG as a layer.
3. Select the correct projected coordinate system that the file is in when prompted.
4. Once the .DXF/.DWG file has been imported, right click on the layer and select "SPLIT - Layer based off Attribute".
5. Select "Feature Description" as the attribute you'd like to split the layer by.
6. Toggle on/off the layers you want included in your KML by checking the appropriate boxes next to the separated layers.
7. Right click the original layer name that all sub layers are listed under and click "EXPORT".
Note that this may be under the layer option in newer versions of Globalmapper.
8. Select KML/KMZ as your export type and save
9. Choose the "Draw Above Terrain (Elevations Relative to Ground Level)" option for 3D Line Export, 3D Area Export and 3D Point Export
10. Uncheck "Extrude Areas (Fill to Ground - Make Buildings)" then click OK.
10. You're done! Import it into Propeller to confirm that the elevations are correct.
Instructions - Exn
If the elevations in the viewer are still not correct, it may be because the height data in your line-work is not equal to the height of the terrain (sometimes the default height in line-work is 0m, for example, or missing).
You can update the height to match the terrain by following these steps:
1. Import the DEM GeoTIFF from the Viewer and load it into Global Mapper. along with the contour files
2. Select both the DEM GeoTIFF and the contour file.
3. Using the Select By Drawing Polygon tool, draw a select region around all the points in the DWG file
4. With the Digitizer Tool selected, right click in the selection.
5. Navigate to "Analysis/Measurement" > "Apply Elevations from Terrain Layers to Selected Feature(s)" then:
- Select "Yes" when prompted to add m or ft attribute.
- Select "No - Assign directly as new values" when prompted.
Your DWG file now has elevation values corresponding to the Terrain elevation instead of the default values that were stored in the KML.
6. Right click on the DWG file and click Layer > Export
7. Select KML/KMZ
8. Choose the "Draw Above Terrain (Elevations Relative to Ground Level)" option for 3D Line Export, 3D Area Export and 3D Point Export
9. Uncheck Extrude Areas (Fill to Ground - Make Buildings then click Save
10. You're done! Import into Propeller to double check that everything is as it should be.
I still can't do it!
We wrote these articles to arm you with everything you need to get the job done on your own, but we understand that sometimes this isn't sufficient.
If you're stuck, the Propeller data specialists team can help for an hourly consulting rate. Email us at firstname.lastname@example.org or talk with us right now from the chat bubble and we'll do our best to help.