Steps for Zonal Operations: Compare Cells by Attribute (Description) or Shape (Geometry) (Especially for GATE-Geospatial 2022)

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Zonal function uses either from a single grid or from other layers to compare cells by either attribute (description) or shape (geometry) . You need to define the zone with which you want to work. In a raster data model, a region (or zone) is a group of grid cells that have the same attributes.

In a zonal operation, the value of a cell in the new raster is a function of the value of that cell in the original layer and the values of other cells which appear in the same zone specified in another raster.

Steps for Zonal Operation

1. Create one input layer, called the zone layer, as the top layer for comparison.

2. Create another input layer that has the values you want to use to evaluate for each zone.

3. Perform the comparison functions for each zone.

Example Shows Zonal Operations

Here, the zones are defined by the Zone grid. The function is zonal sum, which sums all the input cells per zone, and places the output in each corresponding zone cell in the output.

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