On 12/09/12 14:40, Markus Neteler wrote:
On Tue, Jul 17, 2012 at 12:19 PM, Enrico G<[email protected]> wrote:
Hello everybody,
I am trying to understand if GRASS fits me with its v.lrs module and how can
I use it
I have created a (yet minimal) new Wiki page:
http://grass.osgeo.org/wiki/Linear_Reference_System
On the page, there are two articles listed which may be of interest,
I work as a marine surveyor mainly in the offshore oil& gas industry,
occasionly cable& environmental as well.
In this environment, everything is referenced to a (p)line and its offsets.
Offset here are usually meters off a line, + or - outside a line (depending
on bearing), which is a different referencing method than the one used in
v.lrs, correct?
In GRASS, an offset is the distance from a milepost along the line.
I.e.
-------A------------------
0----1----3----4----5----6
--------------------------
-------------------B------
A = KP 1.25 DX = 1
B = KP 4.75 DX = -2
where:
KP = miles post (distance from start of line)
DX = offset
Why is this distance to the line important for you? It won't be
reached anyway if not connected.
v.lrs.create has 'thresh' option to take into account points that are
not exactly on the line.
You might want to use a combination of v.lrs.* + v.distance.
Moritz
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