CRCCalculator
From Fmepedia
CRCCalculator is a Workbench Transformer.
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Description
The CRCCalculator creates a unique ID for a feature based on its geometry and/or attributes. CRC stands for Cyclic Redundancy Check (http://en.wikipedia.org/wiki/Cyclic_redundancy_check).
You can use this CRC value to check data at a later date - to make sure it hasn't been changed, corrupted, deleted etc. It can also be used as a form of ChangeDetection (instead of using the ChangeDetector to compare geometry, use the Matcher to compare CRC values).
The value could also be used as a guaranteed unique ID number within a dataset.
Example
The attached workspace shows an example use of the CRCCalculator transformer.
The CRCCalculator is a great tool for carrying out change detection.
In this example address records are checked against an updated database using CRC values as identification whether a record has been changed. This workspace generates CRC values on-the-fly; an alternative is to save CRC values for each record, to save having to generate them for each run of the workspace. This is the big advantage of using the CRCCalculator over the ChangeDetector.
Workspace Screenshot
