7.5.3. Reproject data to a new coordinate reference system (CRS)
Sometimes, not only one raster file needs to be converted to another coordinate reference system, but a whole folder with many raster images. In this example, the ASTER30_WGS84 DEM will be projected to the CRS CH1903/LV03 of Switzerland.
- Go to Raster.
- Select Projections.
- Choose Warp (Reproject).
- Select single input and output files (e.g. ASTER30_dem_CH1903) or source and destination folders (for processing in batch mode).
- Specify both the source and target reference system (SRS).
- Choose bilinear or cubic as Resampling method.
- Activate the checkbox Load into canvas when finished (Fig. 94).
- Start the projection by clicking OK.
Depending on the type of the raster image values different Resampling methods should be used (e.g.
nearest neighbour for categorized thematic data and bilinear or cubic for
continuous data such as raster images like elevation models). In addition, it
might be useful to define a value for pixels without data (so that they can be
made transparent afterwards).
Fig. 94. Project a raster dataset to a new target coordinate reference system (CRS).