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FAQ: What methods are used to check for attribute and geometry changes in features?

Question

What methods are used to check for attribute and geometry changes in features?

Answer

When the geometry or attribute properties of a feature change, detection of these changes is vital to accurately track the differences in the properties and to make comparisons between the original and new data. The Feature Compare tool can be used to detect changes in features.

The Feature Compare tool allows comparisons to be made by checking if there are any changes in a feature using the ObjectID as the unique identifier. Thus, comparisons can only be made if the feature's ObjectID remains constant. As an example, when working with identical parcel features from two different datasets, if the ObjectID of the parcel from one dataset does not match the same parcel ObjectID from the other dataset, the results of the comparison may be inaccurate due to different ObjectIDs assigned to the same parcel. Additionally, the number of features in the feature classes must be the same when making comparisons using the Feature Compare tool. 

Alternatively, use the Select Layer By Location tool to detect attribute changes of features. This tool requires the input to be a feature layer and not a feature class. Use the Select Layer By Location tool to select the common features in two layers in comparison, and use the Switch Selection option to obtain the attribute changes.
 

Note:
When using the Select Layer By Location tool, adjust the search tolerance to obtain maximum accuracy when detecting changes. 

Starting at ArcGIS for Desktop 10.2.1, the Detect Feature Changes tool is introduced to aid in identifying changes for line features. This tool is not a replacement of the Feature Compare tool, but provides users with the ArcGIS for Desktop Advanced license more detailed information about line feature changes.

To determine where geometries and attributes have changed between two feature classes, use the geoprocessing sample, Compare two feature classes in a file geodatabase, which is available for download from the ArcGIS Code Sharing site.

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