What is DEM precision, should I choose single or double?
DEM precision refers to the number of decimal points to which the elevations of the DEM pixels are recorded. The DEM precision may be set in the Project Options form and can be changed to either option at any stage. Single precision mode will store elevation values to 7-8 decimal places while double precision mode will store elevation values to 15-16 decimal places. Keep in mind that selecting double precision mode will increase disk space, memory and algorithm run-time requirements by approximately 20%. Single precision mode is usually adequate, however, double precision may be useful in DEMs with a very large change in elevation values (say from 1-10000) because the five decimal places on the left side of the decimal point mean that only 2 or 3 decimal places can be recorded on the right side of the decimal point (this usually occurs where the vertical units are not in metres). This presents a real chance that in flat areas of the DEM, or when applying the PFS algorithm with a low mi
