2

I have a shapefile of polygons. Polygons were created in different times (digitized on raster image). I would like to determine the date that specific polygon was created.

Is there any tool that can help to find this out in ArcGIS Desktop?

1
  • 1
    TL DR -- If you didn't record it, you can't tell (and the shapefile date type only stores day resolution)
    – Vince
    Nov 4 '20 at 11:55
8

Apart from the Esri Editor Tracking extension there is no way to determine the 'age' of a polygon in a feature class; note that merge or append operations done outside an edit session will not get entries in the tracking table.

In a geodatabase you could have a reasonable guess based on the OID or OBJECTID field (not FID, that's different) as these IDs are assigned at creation and never change; features can be merged which looks like a reshape and deletion in the database. If you know the date of preceding and following edits from a project number or work order for example a row that falls between can be aged as no older than X and no newer than Y, like ageing fossils based on the soils they are contained in.

In shapefiles the FID is reordered on save, FIDs are always 0 based, contiguous, unique and ascending outside of an edit session with unsaved edits (AKA dirty edit session) so edited records have no relationship with their origin row and are now at the end of the table.

For quite some time GIS data has had metadata capability but this is at a feature class level and not individual features; individual features can have feature level metadata (FLMD) which is a collection of fields containing values that are important, things like install date, last inspection date, owner, installing company, link to receipts etc.. but these are just fields and have no integrity. Feature class metadata is such a pain to deal with that many don't bother unless it's a requirement of policy or client which contains information like data custodian, geoprocessing operations performed, who to call if something is wrong, access and use restrictions, copyright date etc.. some may issue a PDF file with the shapefile mentioning data lineage, use restrictions and copyright dates, this is still metadata but is not XML metadata which is readable in ArcCatalog, has automatically syncing fields and is copied as part of the feature class if you use ArcCatalog to copy or export the data.

1
  • Thanks a lot @Michael for detailed explanation!
    – Sher
    Nov 4 '20 at 23:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.