Hi Cameron,
First of all you need to 'flatten' your table, ie get rid of overlaps
and be left with a table with a polygon for each overlapping area. The
region check tool will show you overlaps, but its output will itself
contain overlaps where there are more than two overlapping polygons in
the original table, as in your case.
1. With a copy of your polygon table, make it editable, and convert the
polygons to polylines using the Objects > Convert to polyline command.
2. Create a new, mappable, table with a smallint attribute named
'Count', call it Polygon_Overlap or something similar, add it to a map
window with the polyline table.
3. Make the Polygon_Overlap table editable, and then select all the
records from the polyline table. Choose the Object > Enclose command,
this should build a set of non-overlapping polygons in the
polygon_overlap table.
4. Now use the Table > Update Column command and fill it in as follows:
Table to Update: Polygon_Overlap
Column to update: Count
Get Value from: Original_polygon_table
(The Join should be where object from Original_polygon_table contains
object from Polygon_Overlap)
Calculate: Count
Hey presto, the count column should be updated with the number of
overlapping objects.
Andrew
Cameron McGregor wrote:
Hi there,
I have a TAB file with 150 polygons. I would like to somehow create a
separate TAB file of where the overlaps take place along with a count of
how many overlaps take place. In some cases only two polygons might
overlap while in other cases 10 polygons could overlap. I have used the
check regions overlap detection tool however it wont give me the count.
Any help would be greatly appreciated.
Thanks
Cam
--
----------------------
Andrew Harfoot
Geodata Institute
University of Southampton
tel: +44 (0) 23 80592719
fax: +44 (0) 23 80592849
[EMAIL PROTECTED]
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