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Batch-Process Data Using Iterator Nodes

Batch-Process Data Using Iterator Nodes

Use an Iterator node to batch-process multiple datasets or, in general, to loop through a group of elements. The output of an Iterator node will be executed as many times as the number of elements passed in, iterating through each of them one-by-one. Using an Iterator node is the same as using a FOR statement in IDL programming.


This example calibrates and runs QUAC atmospheric correction on four input files. It adds the results to the Data Manager:

The next example runs the Multiplicative Lee Adaptive Filter task four times, each using a different Window Size value. Four odd integers are specified in an Array of Values node. Each time the model runs, the Iterator node passes an integer to the Window Size parameter of the filter task. By passing the output images to a View node, you can visually compare the results to determine which Window Size value works best.

The ENVI Modeler does not support nested iterations (loops). This would be similar to adding a FOR loop within another FOR loop in IDL programming. If your model requires a sequence of iterations, close the first loop with an Aggregator node. Then pass the output of the Aggregator node to a second Iterator node to execute the second loop.

See the help topics below for more examples that use Iterator nodes.

See Also

Generate Filename Nodes, Specify Input Datasets and Task Parameters, Collect Items Using Aggregator Nodes, Apply Conditional Statements Using Filter Iterator Nodes, Specify Model Output

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