[GRASS-user] Vector proximity Tools.

[Michael Barton]

V.distance may be what you need.

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton




From: "Sampson, David" <dsampson at NRCan.gc.ca>
Date: Fri, 1 Sep 2006 15:28:42 -0400
To: <grassuser at grass.itc.it>
Subject: [GRASS-user] Vector proximity Tools.

Hey Folks, 

I come back with more questions for "addressing" and geo locations issuesŠ

Looking for a tool that can take a vector file (road segment network) and
point data (FSA Centroids) to relate a road segment with the closest FSA(s).
FSA's are the first three letters of a Canadian Postal Code

SI there a tool in GRASS to check this proximity with VECTOR?  Or do we have
to convert to raster and then back to vector?

Here is the background

1. using PAGC as a program that can do addressing based on blok face road
segments and address ranges (http://www.pagcgeo.org/
<http://www.pagcgeo.org/> )

2. Using the freely availbe road network file from Stats Canada
(http://www.statcan.ca/english/freepub/92-500-GIE/2005001/how.htm
<http://www.statcan.ca/english/freepub/92-500-GIE/2005001/how.htm> )

3. Since postal code position data is not freely available in Canada you can
only realy work with the first three characters (for free at least), or the
Forward Sorting Address (FSA)

4. The FSA list can be found in various places, I like the one on Wikipedia,
although a full QC has not been done
(http://en.wikipedia.org/wiki/List_of_K_Postal_Codes_of_Canada
<http://en.wikipedia.org/wiki/List_of_K_Postal_Codes_of_Canada> )

5. Geoconnections has a gazateer service that will give out a centroid based
on the FSA (one at a time of course)
http://www.geoconnections.org/CGDI.cfm/fuseaction/developersCorner.details/i
d/4517/gcs.cfm 
<http://www.geoconnections.org/CGDI.cfm/fuseaction/developersCorner.details/
id/4517/gcs.cfm> 

The problem is that in the road files there may be more than one MAIN
STREET. So I¹d like another criteria to match againstŠ in the states the
tiger data is good for zip codesŠ but postal codes in canada, well, cost a
lot.  So I'm thinking of the following rationelle

First, I need to create a FSA centroids shape file (that will later be
freely distributed) by running a list of FSA's for a province through the
gazateer.

Then here is where I think GRASS might be able to come in.

Match each roadsegment to the closest FSA centroid(s). Maybe the top three.
Have this info dumped to the table. Export the new road file as a shp file
and use this as reference data for PAGC. This would at least help narrow
down the choices as it is unlikely to have two MAIN STREETS in one postal
code.

This is just an ideaŠ so any input or LIKE experience would be welcome info

Cheers 


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