DWG to GeoTIFF conversion

Why DWG cannot be used directly

DWG files from drone or topographic surveys contain vector data: contour lines, spot elevation points, or a triangulated (TIN) surface. Evaluate requires a single-band raster elevation model in GeoTIFF format, which is a regular grid of elevation values.

Converting DWG to GeoTIFF is therefore not a file format swap. You need to generate a raster surface from the vector data and georeference it correctly before you can upload it.

Tip: Request the GeoTIFF from your survey provider

Drone imagery and point clouds are processed in software such as Pix4D, DroneDeploy, Agisoft Metashape, or Civil 3D. All of these export a DEM or DSM directly as GeoTIFF. That export is the native output of the survey processing, it is more accurate than any surface reconstructed from DWG contours, and it is usually available on request. Ask for it before you convert anything yourself.

Converting a DWG file to GeoTIFF

If DWG is the only deliverable available to you, convert it in a GIS tool. The steps below use QGIS, which is free; Global Mapper follows the same logic with a more streamlined interface and reads DWG and DXF directly.

1. Confirm the coordinate reference system (CRS). Survey DWGs are often drawn in a local or national projected grid without an embedded CRS tag. Ask the surveyor for the exact CRS or EPSG code. Without it, georeferencing is guesswork and your terrain will not align with the project site.

2. Convert DWG to DXF. Most GIS tools cannot read DWG natively for licensing reasons. Use the free ODA File Converter from the Open Design Alliance to produce a DXF. Skip this step if your tool reads DWG directly.

3. Import the file and assign the CRS. In QGIS, go to Layer > Add Layer > Add Vector Layer, load the DXF, and set the CRS you confirmed in step 1.

4. Interpolate the vector data into a raster DEM. In QGIS, open Processing Toolbox > Interpolation and run a TIN or IDW interpolation on the contour lines or elevation points. Choose an output resolution that matches your site: 0.5 m to 2 m is appropriate for most solar site grading.

5. Export the result as GeoTIFF. Use Raster > Conversion > Translate, or set the output format directly in the interpolation tool. Set the output CRS explicitly to one of the systems Evaluate supports, and check that the raster has a single band and no gaps in the data.

Key points to remember before you export:

• Only WGS 84, Web Mercator, and Universal Transverse Mercator (UTM) Coordinate Reference Systems are supported.

• The raster must be a single-band elevation raster. Multi-band files are rejected.

• No undefined or missing values may be present in the raster.

• Elevation values must fall between -500 and 10000 m.

• Maximum file size is 250MB.

• The area the file covers must fall inside your project area.

Accuracy of the converted terrain

Interpolation introduces approximation. The raster you export is only as accurate as the density and quality of the contours or points it was built from, so a DEM exported natively from the survey processing software will always be the better input. For solar site design purposes, a converted surface is usually sufficient.

Crop the raster to the extent you actually need before uploading. A tightly cropped file keeps precision where you need it and reduces the compression applied during processing.

Uploading the converted file

Once you have a valid GeoTIFF, upload it to your project as described in Evaluate custom terrain imports, and select it in the Energy system designer through the Terrain properties.

Note: If your DWG contains layout boundaries rather than elevation data, such as site limits, restricted areas, or road lines, you do not need a GeoTIFF. Convert the file to KML instead and import it into the Energy system designer. See Available import/export formats.