[Qgis-user] Animal movements visualization

[pcreso at pcreso.com]

Hi Alberto,

This is not a simple topic.

It is an area I have worked in intermittently for some time, & you might try a search for comments (probably on Postgis lists?) from a colleague, Ben Madin, a vet working on epidemic tracking & disease propagation in SE Asia. See:

http://download.osgeo.org/osgeo/foss4g/2009/SPREP/3Fri/Parkside%20110A/1300/Madin_Friday_1400.pdf

My experience has been with mark-recapture data for fish & birds. I have found two main issues arise when visualising such data:

1. If you don't have real time GPS tracking data, then the displayed path between known positions are indicative at best. ( eg: A fish was tagged at one side of an island & recaptured on the other - which way around do you draw the line (join the dots), & how do you know it didn't circumnavigate the island or migrate far away & back again in the interim?)

2. In a "network" such as you describe, a static map may show animals at the same place, but this may have been years apart, as you generally lose the temporal side of the data when you plot it spatially. (This may or may not be important)

I have built animations with GMT (Generic Mapping Tools) & interactive 3D visualisations with OpenDX, both of which helped display the spatio-temporal natue of these data. Others I know of have done this using R.

One recommendation: Ensure your data is in a well designed database (or data structures) first. This provides a very necessary foundation for robust analysis & visualisation.

In my experience a good RDBMS model clearly separates the animal & marker entities, & mark/release points, allowing each animal to have multiple markers (concurrent or sequential) and multiple mark & recapture events, with the required assembly into track lines via queries. PgRouting (with Postgis) can be a useful tool for assigning sensible paths between locations, where appropriate.

If your data is in a suitable spatial database, then a tool like QGIS can be used to visualise the points & lines, & some idea of the temporal nature of the data can be made using colors &/or symbols to represent times & animals. Problems still arise, where, for example, you have a point representing a farm, so all animals that were ever there are overlaid at the same point, correctly indicating such a farm as a busy place with respect to the data, but it is not necessarily easy to get to the detail about such points.

If you have more specific questions, feel free to ask email me.

HTH,

Brent Wood


--- On Wed, 10/24/12, Paolo Cavallini <cavallini at faunalia.it> wrote:

From: Paolo Cavallini <cavallini at faunalia.it>
Subject: Re: [Qgis-user] Animal movements visualization
To: qgis-user at lists.osgeo.org
Date: Wednesday, October 24, 2012, 1:07 PM


  

    
  
  
    Il 24/10/2012 01:25, Alberto ha scritto:
    
      
      
      
      
        Hi all,  
           
        I was wondering if
            someone knows any "easy to use"  plugin in quantum gis that
            could be use to draw the network of animal movements from an
            edgelist of movements (origin - destination) and the
            location of farms. 
      
    
    Could you please explain better what you need?

    Thanks.

    -- 
Paolo Cavallini - Faunalia
www.faunalia.eu
Full contact details at www.faunalia.eu/pc
Nuovi corsi QGIS e PostGIS: http://www.faunalia.it/calendario
  


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