As a geographer, I understand the important to have a topologically clean database. However, in the business environment these people really do not care about topology. I explain to my boss the only way you can create an overlapping polygon is to write a GISDK add-in tool, the first thing came out from his mouth is "This is basic function, Why other software can do it but not Maptitude?". I think it is still a good idea to let the end user to decide what they want to have an overlapping polygon or not. So it can accommodate all different types of users.
Louis -----Original Message----- From: Kjartan Stefansson [mailto:[EMAIL PROTECTED] Sent: Thursday, September 16, 2004 8:32 PM To: [EMAIL PROTECTED] Subject: Re: [Maptitude] Overlap areas Chris, Maptitude can create an overlapping area database the way you describe. Also on some imports, it will create overlapping area databases. But aside from these examples, Maptitude does try to maintain correct topology in the database. Whenever you edit a database with overlapping areas, areas affected by your edits will be "cleaned up": Overlaps will become new, separate areas. The main principle here is that Maptitude tries to keep topologically clean databases. This is because most commonly you would NOT want overlaps. In many imported databases from other software you will see that the overlaps are accidental slivers, because the other software either doesn't know or doesnt' care about topology. If you have overlaps, some analysis such as overlay will be incorrect. As you have demonstrated, there are a couple of ways to create overlapping areas in Maptitude. In general, you will find no support in the Maptitude user interface to maintain such databases. If you edit them, overlaps are gone. Sorry! There are ways to maintain such databases if you create special GISDK add-ins, as some people have hinted on this mailing list. But as I described above, the standard editing tools don't support them. If at all possible, I would recommend that you start by looking at some of the several suggested alternative methods mentioned on this mailing list, such as using multiple layers or maintaining overlaps and use multiple fields to flag the different areas and intersections. -Kjartan ----- Original Message ----- From: chris wagner <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Sent: Thu, 16 Sep 2004 18:45:56 -0400 Subject: Re: [Maptitude] Overlap areas > Not to beat a dead horse........ > > Another thought that just came to mind on the overlaps.... > > I have 3000 points in a city > I create .25 mile bands around the points > I select Separate > There are many overlapping areas.... that are all separate and complete > > Maybe working from that we can figure something out > > Chris > > > > > > > Yahoo! Groups Links > > > > > > Yahoo! Groups Links ------------------------ Yahoo! Groups Sponsor --------------------~--> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar. Now with Pop-Up Blocker. Get it for free! http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/C5grlB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Maptitude/ <*> 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/
