[GRASS-user] using LLID numbers with the linear referencing system

Lindsay Mico lindsaymico at hotmail.com
Wed Feb 28 19:13:53 EST 2007

Fellow GRASS users,

I would like to build a new point data layer from a large database of stream 
surveys which have 2 pieces of spatial info:

1) an LLID number for that stream
2) distance from the start of that stream

Based on what I have seen, I would use the linear referencing system 
modules.  I am not sure if I need to build a new reference layer as I have a 
stream layer with the LLID info already in it.  Additionally, I could not 
find an example of how v.lrs.segment works in practice.  I have attempted to 
summarize things as I understand it to help make it easier to answer my 
questions.  As I understand it the input parameters for v.lrs.segment would 
be as follows:

1) input= the stream layer with the associated LLID info
2) output = the name of the output layer
3) llayer = whether it is a point or line (is it 1 for line and 0 for 
4) rsdriver = I don't know what this means
5) rsdatabase = the location of the file with the LLID # and distance
6) rstable = the name of the file which has the LLID number and distance?  
will it automatically add in the other data in the database?  Or do I do 
that later using a spreadsheet program on the .dbf

As I am still learning how to do this, I expect I will have more questions 
in the future.  Hopefully this will be of use to others as well.  Many 
thanks in advance.  Cheers.

Lindsay Mico
Environmental Consultant
Demeter Design LLC
(503) 368-7195
"Thoughtful Planning is the Surest Investment"

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