Relation Between Fires and Distanse to the Nearest Road (Recalculated)

November 29, 2011

(This article was first published on Misanthrope's Thoughts, and kindly contributed to R-bloggers)

As you may already know, I'm a proud owner of AMD FX-8150 8-core CPU. And I've purchased it not for gaming reasons, but for science. My previous CPU was painfully slow with such calculations as determination of the relation between fires and distance to the nearest highway. I even didn't try to perform that calculations on the whole dataset of the roads mapped in OSM in Leningrad region. But now I can do this!

With the new CPU I've recalculated previous distribution (with the same data) in dependence only on highways and performed new calculation on the whole roads dataset. Some numbers first: 
  • 6,990 - number of fire points detected by FIRMS for the last 10 years in Leningrad region;
  • 10,966 - number of the highway features used as highways for calculations;
  • 87,422 -number of features from whole dataset of roads;
  • 2,3 Gb RAM and a single core were consumed by R during calculations for the whole dataset.
Recalculated fire distribution for the highways
Recalculated values for the highways are different to the acquired at the last time despite the data was the same. But there were hardware update and most important - software updates for R and its packages (OS was updated too). But this graph looks far more reasonable than the previous one.

Lets see what we've got for the whole roads dataset (I will compare it to the graph above).
Distribution calculated for the whole dataset of roads
The maximum distance from road decreased almost in to times: from 41 to 26 kilometres. The distance for the highest values decreased accordingly: a rapid decreasing stops at 7 kilometres and for only highways it was 18 kilometres.

So the first 5 kilometres from the road are the most probable zone fore the fire event. This distance is easily covered on foot in two hours. Another evidence of the massive anthropogenic impact on fire starting.

If I will ever lay hands on the road data from the topographic maps (here OSM data used) I will perform the calculation again to get the most precise data.

Conclusion: FX-8150 worth buying )))

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