Issue with mergepoly command

[Michela Giorcelli]

Dear Statalists,
I need to create a map of Italy with provinces for year 1960. I have a shapefile of Italian provinces in 2010, so I need to merge a few provinces that did not exist in 1960. For this reason, I'm using the mergepoly command. The command works, but there are still a few lines between provinces. Is there a way to get rid of those?

Thank you for you consideration.

Regards,

Michela

[Robert Picard]

As explained in the help file, "mergepoly will fail to merge polygons if the shapefile was constructed by combining polygons from other shapefiles without redefining polygons to reflect shared boundaries between adjacent polygons". Presumably, that's what's happening here. I can't say more without access to the problematic shapefile. Can you post it here as an attachment or send it to me by email at [email protected]? I can take a look and see if there's an easy solution.

[Federica Zamagni]

Dear Statalists,
I am facing the same problem of Michela Giorcelli : I am using the mergepoly command to merge merge adjacent polygons from a shapefile (Italian municipalities) by a user-defined variable (precisely, I recoded about 7000 municipalities in 38 groups). The command works, however there, also in my case, few lines remains. Did you manage to get rid of them?

Also, how can I do to "redefining polygons to reflect shared boundaries between adjacent polygons" as the help suggests?

Thank you for your help,
Kind regards,

Federica