Dissolve tool misses out two polygons

[MartinPulicar]

I'm trying to dissolve polygons based on a code number in the attribute table.

It all works well, with an exception of two polygons that fail to dissolve - they literally drop out from the output. It affects always the same two polygons. ArcMap does not give me any error message or anything.

I have tried messing with the source dbf file to see whether there are perhaps some funky characters in the code field, but it seems to be fine. The code is really just a simple number (12 and 707 specifically).

The only thing that seems to have perhaps some relevance is that both of those missing polygons happen to be parts of large cities, therefore they consist of higher number of small polygons to be dissolved (but still nothing that ArcMap could not handle). Other than that I have really zero clue what could be wrong...

Any hint, tip or idea would be much appreciated! Thanks!

I'm using ArcMap 9.3.

[DanPatterson_Retired · Accepted solution]

copy the field codes here so we can have a look  particularly check for an extra space at the end of the text entry assuming it is text

Run a Repair Geometry on the file...may be some funky geometry...are they particularly complex

Just in case...run a MultipartToSingle part on them if repair does nothing

all I can think of now

[MartinPulicar]

Repairing the geometry fixed the problem! I've never used this tool, now I know it can help out from a dead end. Thanks a lot, Dan!

(Just for edit: yes, the polygons were complex. No, there were no extra spaces in the codes.)