[Mapserver-users] Negative Tolerance?

Ryan, Adam ARyan at co.linn.or.us
Mon May 24 11:15:46 EDT 2004

Thanks for the reply.  I negative tolerance is indeed abstract when applied
to a point.

What I want to do is provide an intersect function; I'm thinking polygons.
For example, a user has selected a parcel feature and wants to select all
the survey features that lie below it.  With a tolerance of 0, all the
surveys that only share an edge with the parcel are selected.  I want to use
a small negative tolerance so that only those surveys that actually lie
below it are selected.

So far, a negative tolerance is treated as zero.  Is there another way to do


-----Original Message-----
From: David Fawcett [mailto:David.Fawcett at state.mn.us] 
Sent: Monday, May 24, 2004 7:21 AM
To: ARyan at co.linn.or.us; mapserver-users at lists.gis.umn.edu
Subject: Re: [Mapserver-users] Negative Tolerance?

What are you trying to accomplish?  

I don't believe that it would be appropriate or possible to use a negative
TOLERANCE value, as it defines the radius (in pixels) around a point.  I
can't picture a circle with a negative radius.


David J. Fawcett
MN Office of Environmental Assistance

>>> "Ryan, Adam" <ARyan at co.linn.or.us> 5/21/2004 12:25:49 PM >>>


Is it possible to use a negative number for a layer's TOLERANCE value? 
can't seem to make it work.


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