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ENVIConfusionMatrix::UserAccuracy

ENVIConfusionMatrix::UserAccuracy

The UserAccuracy function method returns a user accuracy value. The result is an array with one value per class.

User accuracy is the probability that a value predicted to be in a certain class really is that class. The probability is based on the fraction of correctly predicted values to the total number of values predicted to be in a class.

In the example confusion matrix, user accuracy is computed as follows:

Asphalt: 2385 / 2394 = 0.996

Concrete: 332 / 333 = 0.997

Grass: 908 / 917 = 0.99

Tree: 1084 / 1093 = 0.992

Building: 2053 / 2071 = 0.991

Example


See the following topics for code examples:

Syntax


Result = ENVIConfusionMatrix.UserAccuracy([, ERROR=variable])

Return Value


This function method returns the user accuracy value from the confusion matrix.

Arguments


None

Keywords


ERROR (optional)

Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.

When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.

See Manage Errors for more information on error handling in ENVI programming.

Version History


ENVI 5.4

Introduced

API Version


3.2

See Also


ENVIConfusionMatrix



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