The elevation (bathymetry) data could be in various gridded formats:
- ArcGIS ASCII Grid (.asc)
- ZmapPlus, Landmark Zmap,
- IRAP classic grid,
- Surfer grids .grd both ascii or binary,
- GeoTIFF single channel floating point elevation raster layer,
- Imagine IMG multi-channel raster image with elevation data channel.
If georeference is not available, this could be supplied by a world file, or be specified manually in the ReportGen geospatial tab menus.
If you have TIN geometry representing a terrain surface, such as from AutoCAD civil or other similar software, the TIN (dxf, dwg, dgn…) could be loaded and used as a terrain surface, with georeference added manually.
All of the above terrain surfaces may have a raster image draped on them. If no georeference is supplied, such a simple PNG or JPEG image, then it assumes the image exactly fits on to the DTM extents. If georeference data is available, from JPG/JPW world file, or as GeoTIFF image, then this data controls the offset, scale and rotation of the image with respect to the DTM.
If the DTM is too large for making a good PDF, then it can be reduced using the Subsample menu, or If any of the above gridded DTM formats are loaded, the resulting PDF can be generated using a TIN representation using the ReportGen gridding TIN menu or the Advanced Simplification menus.