Loading DSM files in TIFF format

DigiNG allows to load files (using the command LOAD_F) with extension .TIF that represent either an orthophoto or a digital model of surfaces.

• If the loaded file represents an image, it will be displayed in the drawing window as any normal reference file. If we expand the file options in the pane Drawing file we can enable/disable the display of the image as well as the type of interpolation when interpolating/extrapolating.
• If on the other hand the loaded file represents a digital model of surfaces, no information will be displayed in the drawing window, however we can use it as a source of Z coordinates for commands like CAL_ORTHO or for the flags that you can find in the menu Photogrammetric window/Project coordinate Z using loaded DTMs or the menu DTM/Project Z when moving over a loaded DTM.

The MDS must be geo-referenced, which means that somewhere information must appear that lets the program know the position of the image as well as its orientation and size. If the MDS is stored in a GeoTiff file, no additional file is needed (as long as the GeoTiff file reports both the position/size of the image and the coordinate system). If it is not a GeoTiff file, you will need a .tfw file (more information in World File for geo-referencement and a .prj file (more information in Shapefile Projection Format) That is, exactly the same as load an orthophoto in DigiNG but with one difference: The reference coordinate systems of the drawing window and the MDS file do not have to coincide, they can be different as long as there is some transformation from one to the other. DigiNG.NET allows loading MDS files in 32-bit and 64-bit Tiff. If you want to learn more about this, read the post Does the TIFF contain an image or does it contain an MDT/MDS? on the Digi3D.NET development blog.