[mapserver-users] distance search in PLSS

[Ed McNierney]

Puneet -

How accurate do you need to be?  The two issues I can think of right off are that you don't know when the current meridian runs out and you need to look at a new one, and the fact that the grids aren't entirely regular and have many hole in them, especially around Indian reservations and other unsurveyed areas.  That is, if you start with T21, R10, S23, the next section to its west will be  Section 22 - IF Section 22 actually exists at all.

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242 

-----Original Message-----
From: Puneet Kishor [mailto:pkishor at GeoAnalytics.com]
Sent: Wednesday, August 28, 2002 11:23 AM
To: mapserver-users at lists.gis.umn.edu
Subject: [mapserver-users] distance search in PLSS


not directly a mapserver question, but...

given a PLSS quarter-section, and a distance (let's assume, in increments of
1/4 mile, since each qs is a quarter-mile square), I want to return a list
of all the quarter-sections and their parent sections, townships, and
ranges. 

For example, if I choose T21, R10, S23, NW, what trsq values would be around
it within a radius of 1/2 mile.

Also, let's assume that I am interested in pass-through selections. So,
every 1/4 mi incremented radius will select the "next" outer set of trsq.

The catch is, I don't want to do this spatially... instead, I want to use a
database... in other words, pure logic and math.

I have a table of PLSS values with fields for t, r, s, qs. PLSS follows a
set pattern. It is reasonable to assume that an algorithm could be devised
to do this on the fly.

Any ideas, anyone?

tia,

pk/