The file B3603Augustine_3_dem.tif contains a linear stretch of the DEM. To reconstruct the z-axis of the DEM in units of mm, 1) multiply TIFF by 0.0374229 2) Add -9.54284 The x & y scales are 0.030 mm / pixel. Maximum value for DEM, corresponding to TIFF value of 255: 0.00000 Minimum value for DEM, corresponding to TIFF value of 0: -9.54284