Hi,
This should do the trick:
Select TABLE_A.ID, TABLE_B.ID, CartesianArea(Overlap(TABLE_A.OBJ, TABLE_B.OBJ), "sq m") "AREA_SQ_M"
From TABLE_A, TABLE_B
Where TABLE_A.OBJ Intersects TABLE_B.OBJ
You might also want to add this condition to remove all the cases where an OBJ in TABLE_A only intersects an OBj in TABLE_B
And CartesianArea(Overlap(TABLE_A.OBJ, TABLE_B.OBJ), "sq m") > 0
You can run the entire SQL Statement from the MapBasic window or use the SQL Select dialog:
Select Columns: TABLE_A.ID, TABLE_B.ID, CartesianArea(Overlap(TABLE_A.OBJ, TABLE_B.OBJ), "sq m") "AREA_SQ_M"
From Table(s): TABLE_A, TABLE_B
Where TABLE_A.OBJ Intersects TABLE_B.OBJ
And CartesianArea(Overlap(TABLE_A.OBJ, TABLE_B.OBJ), "sq m") > 0
HTH,
Peter Horsbøll Møller
GIS Developer, MTM
Geographical Information & IT
COWI A/S
Odensevej 95
DK-5260 Odense S.
Denmark
Tel +45 6311 4900
Direct +45 6311 4908
Mob +45 5156 1045
Fax +45 6311 4949
E-mail [EMAIL PROTECTED]
http://www.cowi.dk/gis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of shamas
Sent: Sunday, March 19, 2006 2:11 PM
To: mapinfo-l@lists.directionsmag.com
Subject: [MI-L] polygon overlay(calculating area share from differentpolygons)
Greetings all
I am a beginner user of MapInfo. The problem looks to be simple but I am stuck with it.
I have two maps with polygons say table A and B. I want to calculate which polygons from table B overlay each polygon in table A and what is the share of area from corresponding polygons in Table B.
I have tried to use update column and join the table using the "polygon from Table A intersects Polygon from Table B" but it just returns one polygon from the Table B intersecting with polygon from table A while others are not.
I would much appreciate if someone can help me with this problem.
Regards
Shamas
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