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How is a zonal statistic calculated in ArcGIS?
With the Zonal Statistics tool, a statistic is calculated for each zone defined by a zone dataset, based on values from another dataset (a value raster). A single output value is computed for every zone in the input zone dataset.
Can you do zonal analysis for overlapping polygons?
If the zone feature input has overlapping polygons, the zonal analysis will not be performed for each individual polygon. Since the feature input is converted to a raster, each location can only have one value. An alternative method is to process the zonal statistics iteratively for each of the polygon zones and collate the results.
How does the zone layer work in ArcGIS?
In the following illustration, the Zone layer demonstrates an input raster that defines the zones. The Value layer contains the input for which a statistic is to be calculated per zone. In this example, the maximum of the value input is to be identified for each zone.
How are zonal statistics used in Spatial Analyst?
Available with Spatial Analyst license. Calculates statistics on values of a raster within the zones of another dataset. A zone is defined as all areas in the input that have the same value. The areas do not have to be contiguous. Both raster and feature can be used for the zone input.
How are the zones defined in zonal statistics?
The zones can be defined by an integer raster or a feature layer. Field that holds the values that define each zone. It can be an integer or a string field of the zone dataset. Raster that contains the values on which to calculate a statistic. Statistic type to be calculated.
What does the nodata mean in zonal statistics?
NODATA — Within any particular zone, if any NoData cells exist in the Value raster, it is deemed that there is insufficient information to perform statistical calculations for all the cells in that zone; therefore, the entire zone will receive the NoData value on the output raster. The output zonal statistics raster.