Fails to open geotiff due to unsupported format `GrayFloat32`

To start a map, I downloaded some digital terrain model data for France as a geotiff from [this website](https://cartes.gouv.fr/telechargement/IGNF_MNT-LIDAR-HD). When I go to open this data in OOM as a template, it fails with the following error: ``` Cannot open template /home/dmk/Downloads/LHD_FXX_0757_6276_MNT_O_0M50_LAMB93_IGN69.tif: Unsupported raster data: GrayFloat32 Unable to read image data ``` I imagine this is because the tif is a 1D grayscale image. First, is this expected behavior? Second, is there a way to transform this file to get it into OOM? I can contour it as linestrings or polygons in other software, but it would be nice to be able to import the original image for all the finescale features.