John.. reasonably easy if you can make a copy of the table... less so if you want to avoid a copy.
Copy method.... first ensure your table has a unique row identifier then make a copy of the table then use the following sql (substitute the table and column headers for your own) Select table1.id, copy1.id, proportionoverlap(table1.obj,copy1.obj) from table1, copy1 where table1.obj intersects copy1.obj And table1.id <> copy1.id into Selection Browse * From Selection no copy method.... I did have some code to do this in mapbasic but as usual i cant find it ( i will email if i can find it)... but in essence you trawl thru a "select *" query of the table with a fetch statement, copy the query object into a variable (and its row ID !) and then perform a proportion overlap of the variable object with the original table. you then either append all the subselects into a prmanent table (messy) or trawl each subselect and populate two arrays (one for the id and one for the overlaps) then use these as needed or dump out to a text file/ new table in a single pass.(equally messy) hth R -----Original Message----- From: CDR Group [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 01, 2003 6:00 PM To: MapInfo List Server Subject: MI-L Proportion Overlap Sunny Listers I have the SQL to detect the proportion overlap of polygons in separate layers (why isn't that function even mentioned in the help file??) Can anyone help with a tool that detects/queries the proportion overlap of polygons in the same layer... Pretty please John Ievers CDR Group www.cdrgroup.co.uk ********************************************************************* This e-mail message, and any files transmitted with it, are confidential and intended solely for the use of the addressee. If this message was not addressed to you, you have received it in error and any copying, distribution or other use of any part of it is strictly prohibited. Any views or opinions presented are solely those of the sender and do not necessarily represent those of the British Geological Survey. The security of e-mail communication cannot be guaranteed and the BGS accepts no liability for claims arising as a result of the use of this medium to transmit from or to the BGS. The BGS cannot accept any responsibility for viruses, so please scan all attachments. http://www.bgs.ac.uk ********************************************************************* --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 7458
