CalculateZoneMetrics Task

AgCalculateZoneMetrics Task

This task calculates statistics on individual zones contained in an ENVIAgZones object.

This task requires a separate license for the ENVI Crop Science Module; contact your sales representative for more information.

Example

This example uses a DEM as the basis for splitting a field into five management zones. The example uses AgCreateZones Task to create the zones, then it calculates and prints metrics for each zone.

; Start the application

e = ENVI(/HEADLESS)

; Open a DEM file

File = Filepath('FieldDEM.dat', $

  Subdir=['data','crop_science'], $

  Root_Dir=e.Root_Dir)

Raster = e.OpenRaster(File)

; Create a zones object

zonesTask = ENVITask('AgCreateZones')

zonesTask.INPUT_RASTER = Raster

zonesTask.MINIMUM_AREA = 2023

zonesTask.NUMBER_OF_APPLICATION_CATEGORIES = 5

zonesTask.Execute

; Calculate zone metrics

metricsTask = ENVITask('AgCalculateZoneMetrics')

metricsTask.INPUT_RASTER = Raster

metricsTask.INPUT_ZONES = zonesTask.OUTPUT_ZONES

metricsTask.INPUT_ZONE_RASTER = zonesTask.OUTPUT_RASTER

metricsTask.Execute

outZones = metricsTask.OUTPUT_ZONES

; Print the properties of the output zones object

Print, outZones

Syntax

Result = ENVITask('AgCalculateZoneMetrics')

Input parameters (Set, Get): INPUT_RASTER, INPUT_ZONE_RASTER, INPUT_ZONES, OUTPUT_ZONES_URI

Output parameters (Get only): OUTPUT_ZONES

Parameters marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Parameters marked as "Get" are those whose values you can retrieve but not set.

Input Parameters

INPUT_RASTER (required)

Specify a single-band raster from which zone metrics will be computed.

INPUT_ZONE_RASTER (optional)

Specify the zone classification raster that corresponds to the input zones. It allows metrics to be calculated faster for large images.

INPUT_ZONES (required)

Specify an input ENVIAgZones object.

OUTPUT_ZONES_URI (optional)

Specify a string with the fully qualified filename and path of the output zones.

Output Parameters

OUTPUT_ZONES

This is a reference to the output ENVIAgZones object. In addition to the standard ENVIAgZone properties, the output object will also contain the following properties:

SOURCE_RASTER_NCOLUMNS: The number of columns in the source raster
SOURCE_RASTER_NROWS: The number of rows in the source raster
SOURCE_RASTER_SPATIALREF: The spatial reference of the source raster
ZONE_MAX: The maximum pixel value for each zone
ZONE_MEAN: The mean pixel value for each zone
ZONE_MIN: The minimum pixel value for each zone
ZONE_STDEV: The standard deviation pixel value for each zone