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CRCCalculator

Calculates a CRC (Cyclic Redundancy Check) value for a feature and places the calculated CRC value into the attribute specified.

If a CRC is calculated for both coordinates and attributes, it is returned as a hexadecimal string representing an integer of double the bit-length of the chosen algorithm. If a CRC is calculated for only coordinates or only attributes, it is returned as a hexadecimal string representing an integer equal to the algorithm bit-length.

The output format is xxxxxxxxyyyyyyyy, where the x's represent the CRC calculated for coordinates, and the y's represent the CRC calculated for attributes.

Input Ports

Output Ports

Parameters

Usage Notes

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).

Like all popular CRC algorithms, different features could produce the same CRC value with minimal probability.

Example

This FME Knowledge Center example shows an advantage to using the CRCCalculator over the ChangeDetector.

Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

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