Friday, 20 March 2015

Heatmap Haliaetus

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Every single day and every word you say,
  Every game you play, every night you stay,

  I'll be watching you...”

Every Breath You Take  
Sumner, Matthew, Bogdanovic, Dusan (1983)

What did you do this weekend? Did you perhaps go shopping, use an ATM machine, buy a cinema ticket, hop on a bus or drive past a traffic monitoring camera? Whatever you did, somewhere a computer programme made a record of that stuff – the time, the place, the distance, the amount - and added it to a list of similar activities that other people did before you.

When Every Breath You Take was written, back in 1983, the song's sinister vision of surveillance and obsessive control did not encompass today's reality. The application of Geographic Information Systems (GIS) as a way of drawing meaningful intelligence out of large data sets, outstrips anything that could have been imagined by Sting, Orwell or Verne in their day.

The concept is simple enough: Take a list of data points, each one having a set of attributes to be studied and some form of location on a known co-ordinate system. The co-ordinates might describe any kind of spatial relationship: from bacteria growing on a Petri dish to aircraft flights on a map of the entire globe, or anything in between. Once that lot has been loaded up, the fun stuff can begin – for this is the kind of thing that computers are very VERY good at...
 Consider the movements of Premier League football players on a soccer pitch. During the course of a single game, the participants will roam all over the playing area. If we could obtain a table of ALL these movements (and these days, we can) and plot them on a diagram, the end result would just be a visually-confusing web of tracks and changes of direction. But by subjecting the same data to GIS processing, it becomes possible to highlight which zones the defence occupied, and which paths were favoured by the attackers before a goal was scored. Soccer, rugby and tennis coaches are now using these techniques every day, as their players carry tiny portable GPS dataloggers during training and competition. Even the referees are not exempt from this post-match scrutiny, although some of them are less than happy about such developments!

It's not all Big Brother. GIS analysis is not just used to keep an eye on us: it can benefit us and help to keep us safe. Architects use GIS to draw up the fire-evacuation plans for large buildings. It optimises ambulance routings and can predict areas of overcrowding in public spaces.

And these days, even ospreys are coming in for some analysis...

QGis "Brighton" 2.6 User interface
 I have installed a software package called QGis 2.6. Like all GIS programmes, it is horribly complicated and difficult to use, but the results are rewarding. The image at the top of this page shows the activity summary (known as a “heatmap”) for Kielder osprey Blue 7H during her stay in Morocco. GIS allows us to select different ways of looking at the data. It can measure how close one point is to another, or how many occur within a specified area. In this case, we told the computer to analyse only those points where the bird was moving, and to keep a running total of how many there were in any 200-metre radius. The result above should give an indication of 7H's favourite hunting areas, but puts less emphasis on places where she was perched or roosting.

We did a similar exercise on UV's data during his stay in Portugal and obtained very accurate results. (This heatmap has not been published because we expect him to use the same locations in future seasons)

As far as we know, no-one in Europe has used these tools to gain a picture of osprey hunting behaviour before. As the material builds up, it is hoped that the exercise will provide more insights and understanding of this subject, as it is potentially important for conservation work.

7H at Azemmour (Vic Paine)
Every dive you make, 
Every fish you take,
I'll be watching you...


[Data source:  Forestry Commission England satellite tracking]

QGis Software Project: