[R-sig-Geo] environmental heterogeneity

[Rainer M Krug]

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On 16/03/12 12:14, Andy Hartley wrote:
> Dear Pascal,
> 
> I did something similar using Mahalanobis Distance in order to assess similarity of habitat
> within protected areas to that of the surrounding

As you state, the Mahalanobis Distance measures the distance (i.e. dis-similarity) between two 2D
areas - another measure for this is the earth movers distance (one package on cran, one on r-forge
( http://r-forge.r-project.org/projects/earthmovdist/ )

But I think the OP was looking fior a measure of "environmental heterogeneity", which could not be
done with these distance measures easily. I would be interested in the answers.

> area, in Africa. We used elevation, aridity, NDVI, NDWI, etc, so it appears to match with your
> needs. The advantage of using mahalanobis distance (as opposed to euclidean distance) is that
> it accounts for covariance between your input variables. You can read more in our report

I'll look into it, as I used the earth movers distance for a paper.

Roura-Pascual, N. et al., 2010. Spatially-explicit sensitivity analysis for conservation
management: exploring the influence of decisions in invasive alien plant management. Diversity and
Distributions, 16, pp.426-438. Available at: http://www.sciencemag.org/content/312/5781/1715
[Accessed October 14, 2011].

If you can not get hold of the pdf, please contact me off-list.

Cheers,

Rainer


> - http://bioval.jrc.ec.europa.eu/APAAT/AssessmentOfAfricanProtectedAreas_E UR22780.pdf or on
> the webpage - http://bioval.jrc.ec.europa.eu/APAAT/ (click a protected area on the map, and
> scroll down to the habitat irreplaceability indicator)
> 
> Kind regards,
> 
> Andy
> 


- -- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology, UCT), Dipl. Phys.
(Germany)

Centre of Excellence for Invasion Biology
Stellenbosch University
South Africa

Tel :       +33 - (0)9 53 10 27 44
Cell:       +33 - (0)6 85 62 59 98
Fax :       +33 - (0)9 58 10 27 44

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email:      Rainer at krugs.de

Skype:      RMkrug
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