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Recently I had to hand in a FGDB to state authorities. I did all topology checks and corrections as defined in their specifications (see list below). My collegue did a cross check on a the same FGDB. We are a hundred percent sure that all errors and topology issues were fixed. We handed in the data and it came back with a list of errors.

We thought this cannot be true and ran another check on our data (exactly the same checks on the data we handed in). We couldnt believe our eyes, the errors mentioned by the authorities were reproducable.

How can this be possible? What have we possibly done wrong? Could it be a server problem? Or are the somewhat strange tolerances given in the original FGDB responsible for such problems? Has anyone experienced similar issues?


Required topology checks:

  • no multipart features --> we used dissolve / explode multiparts (editing session) / multipart to singlepart tools
  • no features smaller than 20 m2 --> we used the eliminate features tool
  • FC1 must be inside FC2, FC2 must be inside FC3, etc. --> topology checks

Our work environment:

  • ESRI ArcGIS 10.3, Advanced License
  • FGDB on a server
  • cluster tolerance required for topology errors: 0.01 m
  • however, the empty FGDB sent to us by the authorities that needed to be filled with data had the following tolerances set:

fgdb_settings

  • Those are incredibly small numbers. 0.0001 is one-tenth of a millimetre, and they have the XY Resolution at 2 orders of magnitude smaller than that, in the micron/micrometre range, a millionth of a meter. Is that really correct? It doesn't smell right unless the data is medical imaging or something. – matt wilkie Jul 11 '17 at 16:31
  • Also see gis.stackexchange.com/questions/8650/… – matt wilkie Jul 11 '17 at 16:37

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