The “Resample” tool in TerrSet and ArcGIS applies the same “Nearest Neighbor” algorithm (assigning the input cell value closest to the output cell center). But the output from these two software can be different depending on the parameters specified.
When the X and Y extent is not exact multiples of the output resolution, ArcGIS keeps the coordinates of lower left corner pixel of the image and cuts off the upper and right side of the image to round off the extent in order to match with the output resolution. In TerrSet, all the parameters (columns, rows, Minimum X, Minimum Y, Maximum X, and Maximum Y) can be set by the user. The resolution of the output image will be set using the following formula:
X Resolution = (Maximum X – Minimum X) / Number of columns
Y Resolution = (Maximum X – Minimum X) / Number of rows
Users can set the extent or resolution by setting these parameters. If users set the same parameters in ArcGIS, the output image will be identical as Idrisi. If the parameters are different, the output images might be different because the center position of output cells are different.
Specifying the cell size in “Environment Setting” in ArcGIS maintains the coordinates in the upper left corner while cutting off the lower and right side of the image to round off the extent in order to match the output cell size.