Archiving scenarios

Geodatabase archiving allows you to analyze your data as it changes over time. The archive class and the Geodatabase History Viewer can act as useful problem-solving tools. The following are some hypothetical scenarios where geodatabase archiving can be used:

A fire marshal mapping a forest fire can implement geodatabase archiving to help monitor the spreading flames. By creating edits based on the fire's perimeter and saving these edits continually in twenty-minute intervals, the marshal can build an archive of the fire boundary over time. He may then use the geodatabase history viewer to switch to important moments in the fire's history. For example, if the wind picks up and the fire's intensity increases and becomes unpredictable, the marshal can switch to a time prior to this event and view how the fire was situated before. This may help determine where to allocate resources in an attempt to contain the spreading.

If the same fire marshal wanted to see how the fire has spread over time, he could add the fire perimeter archive class to the map. As the fire's boundary changes with the fire spreading, its perimeter is edited and updated in the archive class every twenty minutes. By color-coding the fire's perimeter based on the gdb_to_date field, the marshal can view every instance of the perimeter over time. The resulting map will show a different colored ring every twenty minutes, depicting the expanding boundary of the fire.

A similar example is helpful in parcel management. As edits are made to parcels over time, they can be kept in the archive class. If you want to view how the parcels looked at a certain moment—for taxation purposes, for example—you could use the geodatabase history viewer to switch to the appropriate date and time. If instead you wanted to see how a certain parcel has changed over time, you could add the parcel archive class to the map and select the appropriate parcel by its ID number. This would show every representation of the selected parcel through time.