Hi Users
Here is my spatial challenge.
Suppose I have a mapsheet with X polygons and I want to buffer one at the time using
incremental distance and to perform an "intersect" SQL query on the buffer object.
Let me explain:
I have two layers:
One with infestation polygons. Usually with small polygons.
Other with base polygons.
The base polygons cover the entire landscape and the infestation polygons are very
small in size if compared with base ones.
The idea is to associate indexes to the base polygons that depend of the distance of
each polygon to the infestation and size of the infestation.
EX: if a base polygon "A" is at distance "D" of an infestation "I" of size "S", the
base polygon would get and index "X".
I thought on to create a progressive or incremental distance buffer around the base
polygon and at each buffer increment do a test to check if the buffer intersects any
infestation. If doesn't intersect then do another buffer increment and proceed
testing until the distance of 4 Km. If there is no intersection, the index is Zero.
This procedure has to be performed on one polygon at the time and I have hundreds of
polygons.
After this incremental buffer plus test is done, the buffer should be discarded and
the "pointer" moves to another base polygon. This way after exhausted the base map,
all the landscape would be indexed based on the distance and intensity of the
infestation.
I see some trouble before hand. The buffer can be generated in the same layer or in
the cosmetic layer. But the SQL intersects works on all the objects if I generate in
the same layer. If I save the cosmetic layer to consider only one buffer on the
selected base polygon I would have thousands of single buffer layers. Out the fact I
have to open each one new single buffer layer, perform the SQL/Intersects and close it
...and do it again. It seems way too convolute for me.
Can anyone shed some light here?
I would appreciate any help or questions for further explanations.
Dyan C. Catamaran
GIS/RS Coordinator
---------------------------------
Phero Tech Inc.
www.pherotech.com
[EMAIL PROTECTED]
P:604-940-9944
F:604-940-9433
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