Update Accuracy Assessment Points (Spatial Analyst)

Available with Spatial Analyst license.

Available with Image Analyst license.


Updates the Target field in the attribute table to compare reference points to the classified image.

Accuracy assessment takes known points and uses them to assess the validity of the classification model.


  • Update the attribute table of a feature class that represents accuracy assessment points. If you created the feature class using the Create Accuracy Assessment Points tool, there will be a field for GROUND_TRUTH and for CLASSIFIED. This tool can start with either reference data and compare it to the classified output, or it can start with the classified output and compare that to reference data.

    These two fields are then compared using the Compute Confusion Matrix geoprocessing tool.

  • You can manually update the GROUND_TRUTH field if you want to change or identify a set of points.


UpdateAccuracyAssessmentPoints(in_class_data, in_points, out_points, {target_field})
ParameterExplanationData Type

The input classification image or other thematic GIS reference data. The input can be a raster or feature class.

Typical data is a classification image of a single band, integer data type.

If using polygons as input, only use those that are not used as training samples. You can also use land-cover data in shapefile or feature class format.

Raster Layer; Mosaic Layer; Feature Layer

The point feature class providing the accuracy assessment points to be updated.

All points from this input will be copied to the updated output feature class, and the target_field will be updated from the input raster or feature class data.

Feature Layer

The output point feature class which contains the updated random point field for accuracy assessment purposes.

Feature Class

Specifies whether the input data is a classified image or ground truth data.

  • CLASSIFIEDThe input is a classified image. This is the default.
  • GROUND_TRUTHThe input is reference data.

Code sample

UpdateAccuracyAssessment example 1 (stand-alone script)

This example updates the points used for accuracy assessment.

import arcpy
from arcpy.sa import *

arcpy.gp.UpdateAccuracyAssessmentPoints("aapnt1.shp", "grndtru.tif", "aapnt2.shp", "GROUND_TRUTH")


This tool does not use any geoprocessing environments.

Licensing information

  • Basic: Requires Spatial Analyst or Image Analyst
  • Standard: Requires Spatial Analyst or Image Analyst
  • Advanced: Requires Spatial Analyst or Image Analyst

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