If you export a two-non-overlapping-polygon region, you will get exactly the same MIF structure. The answer to the original question is that there is no way to find in a MIF file if a region contains a donut or not. MI does not seem to use that concept; it is only when it builds a region for display that the donut will appear.
The question about identifying a donut-region has been discussed several times on this list. I have not registered a particularly efficient way to deal with it. One possibility is to explode a multi-polygon region into its constituent polygons and compare the sum of their areas to the area of the original region. If sum>original, there is a donut situation (but that does not identify where the donut is) Jacques Paris e-mail [EMAIL PROTECTED] MapBasic-MapInfo support http://www.paris-pc-gis.com -----Original Message----- From: Nicolas Muszynski [mailto:[EMAIL PROTECTED] Sent: 12-Aug-04 10:19 To: [EMAIL PROTECTED] Subject: RE: MI-L donut polygons All you have to do is define a region with 2 regions and list them one after the other with the number of nodes, if you export a doughnut you will see in the MIF file the following structure: Region 2 10 -0.203947 0.730263 -0.019737 0.736842 0.217105 0.631579 0.388158 0.526316 0.763159 0.230263 0.953947 -0.598684 -0.322368 -0.644737 -0.980263 0.144737 -0.736842 0.447368 -0.203947 0.730263 8 -0.039474 0.328947 -0.256579 0.171053 -0.013158 -0.098684 0.388158 -0.098684 0.210526 0.138158 0.098684 0.230263 0.026316 0.342105 -0.039474 0.328947 Pen (1,2,0) Brush (1,0,16777215) Center 0.54258 0.046052 Hope this helps, Nicolas Muszynski -----Original Message----- From: Tamar Bakker [mailto:[EMAIL PROTECTED] Sent: 12 ao�t 2004 07:35 To: [EMAIL PROTECTED] Subject: MI-L donut polygons Hello listers, I'm importing donut(island) polygons into MapInfo. Because I want to generate a MIF file with donut polygons, I would like to know how the converter in MapInfo decides if a polygon is just a normal multipart polygon or if it's a polygon with holes in it. I can't recognise anything that says it's a donut polygon. Or does anyone know a fast equation that calculates if all the nodes of a certain polygon are situated within another polygon? Does anyone know? Thanks a lot greetings Tamar --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 12940 --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 12943 --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 12944
