HOW TO

# Calculate the maximum difference between a grid cell and it's neighbours

Last Published: April 25, 2020

## Summary

Using a 'kernal file' will restrict the analysis to the neighbours surrounding the cell currently being processed. Some simple mathematical evaluations will lead to the final result.

## Procedure

1. Create a text file (any_name.txt) with the following four lines:

`   3 3   1 1 1   1 0 1   1 1 1 `

Make sure you type a return after the last number.

2. Determine the maximum and and minimum values around the cell.

`Code:  Grid: fmax = FOCALMAX (in_grd, IRREGULAR, donut.txt)  Grid: fmin = FOCALMIN (in_grd, IRREGULAR, donut.txt) `

3. Determine the difference between the cell and the max/min values.

`Code:  Grid: diffmax = ABS (fmax - in_grd)  Grid: diffmin = ABS (in_grd - fmin)`

4. Assign the maximum difference to the output grid.

`Code:  Grid: finaldiff = MAX (diffmax, diffmin)`

Article ID:000002114

Software:
• ArcMap 8 x

Get help from ArcGIS experts

Contact technical support