There seems to be a lot of questions going unanswered out here
these days.
Anyway, I assume your radio frequency records are implemented as
region objects? If so then the key function you'll want to look
at is overlap(). Its syntax is:
object3 = Overlap (object1, object2)
To see if there actually was an overlap between the two objects
you would just test object3 to see if it had any area or
perimeter. (There is no explicit way to test for a "null" object
in MapBasic, but indirect tests will do the job.)
If your overlapping objects are in separate layers, then you can
do this in one SQL select, but if they are in the same layer the
problem is harder. In some SQL systems you can do this by joining
a table against itself using table aliases, but I don't think
MapInfo can handle this. I MapInfo, you could make a copy of the
table and compare objects that way, then throw away the copy when
you're done. Use the rowid to make sure that you aren't testing
the same object overlapping itself in that case.
Personally, I would probably use MapBasic to do this, and not
have to make copies of tables, but from your message it isn't
clear whether by "script" you mean something that runs in the
MapBasic window or a MapBasic program.
- Bill Thoen
TMCNEIL wrote:
>
> A co-worker of mine has separate .Tab files of overlapping radio
> frequencies across the US. he is interested in creating a script that
> will return the intersections, which ones overlap, and the amount of
> overlapping intersections. I am wondering if anyone has ever done
> this before in their type of work. I think I can modify the
> mutli-layer select script to start with, but I would need help from
> there.
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