[Qgis-user] calculate movements along line

[Alex Mandel]

On 04/25/2013 01:47 AM, watercress at gmx.de wrote:
> Hi all,
>
> I am working with relocations from a telemetry study. I want to
> calculate the movement in meter over time along a physical boundary.
> There a some methods to calculate the distance between points along a
> line but since there are different individuals and the movement distance
> has to be correctly calculated by time this does not seem to work for me.
>
> The point-shape with 500 relocations of 30 individuals  looks something
> like this:
> -------------
> ind, date
> 1,2012-08-05
> 1,2012-09-07
> 1,2012-10-15
> .
> .
> 2,2012-08-05
> .
> -------------
> I was thinking of creating a line-shape with a given chainage (splitted
> every x meters?)
> perform a buffer and finally an intersect with the point-shape. But
>
> 1.
> how can I create a line-shape that is splitted every 10 meters..
>
> 2.
> and how to write the chainage into the table
> -------------
> chainage
> 1.540
> 1.200
> 0.450
> .
> .
> 1.800
> .
> -------------
>
> The resulting point-shape should look likes this:
>
> -------------
> ind, date, chainage
> 1,2012-08-05, 1.540
> 1,2012-09-07, 1.200
> 1,2012-10-15, 0.450
> .
> .
> 2,2012-08-05, 1.800
> .
> -------------
>
> my approach seems to be a bit antiquated and clumsy
> but I am capable of learning. Any suggestions or any mistake made by me?
> Thanks,
> Jens
>
>

My suggestion is to use use Postgis or Spatialite. What your trying deal 
with is often called a Linear Referencing system.

Enjoy,
Alex