mariolndry wrote: > > I'm converting an area polygon of the Saint-Laurence river which > includes the island of that river by using tab2tab.exe. I'm > converting from mid/mif to tab. Because the area is filled, the > islands are also filled which means that I don't see the islands if > I open the Tab file with MapInfo, unless I modify the display in > such a way that there is no more fill. In that cas I do see the > islands. But if I open the original mid/mif file with MapInfo I see > the islands and the Saint-Laurence river is filled. Everything > looks Ok. > > Is there something wrong with the tab2tab program? >
It's a limitation of MITAB. The MIF/MID format doesn't include the information as to which islands are holes and which ones are actual separate polygons, but the TAB format does include and require that information. I forget what MITAB does by default, but I think it just assumes that the first ring in a multipolygon is solid fill, and the rest are holes... or does it assume that all islands are to be filled? I don't remember. Anyway, the issue is that the MIF/MID file doesn't include enough information to properly reconstruct the multipolygon, and MITAB doesn't contain any logic to figure that out, and possibly writes the wrong information by default in the TAB file that it creates. OTOH, MapInfo does include the logic to figure which rings are holes and which ones are not. Daniel P.S. Of course it would be possible to add the required logic to MITAB. If you have access to some funding and are interested in funding this enhancement you can contact me off-list. -- ------------------------------------------------------------ Daniel Morissette [EMAIL PROTECTED] DM Solutions Group http://www.dmsolutions.ca/ ------------------------------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/mitab/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
