I was trying to combine many feature classes from one geodatabase into one feature class. All input feature classes have the same schema and all features are line and have the same attributes. The total number of line features is big (~ half million). I noticed quite a bit of features are missing after merging/appending. I tried both scripting (arcpy merge_management and append_management function) and using merge and append tool in ArcToolBox, I even tried to repair geometry first before merge, define extent before merge..,none of these seem to fix the issue. When I changed the computer, the missing issue still existed, just the number of missing features are different. Any suggestion or did anyone here experience this before? Did I miss anything when using merge/append? Thanks.
Without seeing the data we can only guess, if after a merge you have less lines, may be they are very small and falling below the tolerance of the dataset and are collapsing to NULL geometry and are dropped?
Thanks for your reply Duncan Hornby It looks the missed lines are not small and they were chopped out by some kind of extent. I am happy to share the data if I know how to upload geodatabase here. It seems I can't find how to upload data on this discussion page (relatively new here:-).