﻿ Multitple Grid Arithmetic

Multitple Grid Arithmetic (Map Algebra)

• Difference between two grids (entire grid)
• Difference between two grids (current map area only) When you pick the two DEM, DEM1 - DEM2, DEM1, the first one selected will determine the area used.
• Difference maps to all other open grids
• Add multiple grids--add several grids together to create a new grid.
• Ratio of two grids
• Multiple Grid statistics--creates DEMs with the number of points averaged, average (mean), standard deviation,  median, floor (lowest), ceiling (highest), and envelope thickness.
• Minimum of two grids
• Change map: make a new grid with a value of 0 where the two grids are identical, and 1 where where is change.  If the original grids are floating point, enter a tolerance to use for the change comparison.
• Difference elevation, slope, aspect maps: pick two DEMs, and the difference between them for the three parameters plus the vector normals will be computed
• Grid average/std dev (multiple grid statistics)
• RMSE

Last revision 2/15/2023