[R] SDMTools package - calculating overlap?
David Winsemius
dwinsemius at comcast.net
Mon Jul 18 15:45:11 CEST 2011
On Jul 18, 2011, at 9:40 AM, Ana Kolar wrote:
> Dear R users,
>
> Any idea of how to calculate an area of an overlap between two
> functions? The only R build in function that I found is I Similarity
> Statistic for Quantifying Niche Overlap and I am really not sure if
> this function is producing exactly what I am interested in since I
> was plotting functions and often got confused results (for example:
> got high value for the overlap of one pair and low for the other
> pair, while from the plot it looked like the first pair was
> overlapping better.) Can anyone please explain what's the reason
> behind such a behaviour? And does anyone has a suggestion of what
> function could be used for a calculation of an overlap area? The
> problem with 'Istat' function is also that it requires both data
> sets to have the same length, while I would be more interested in a
> function that enables overlap calculation even if data sets have
> different length. Looking forward to hearing from you! Have a good
> day. Ana
Shouldn't you be integrating their difference (or the absolute value
of their differences depending on your definition of "overlap"). I
fail in understanding your example. Where is/are the function(s)?
>
> library(SDMTools)
> a <- matrix(runif(30))
> b <- matrix(runif(30))
> Istat(a,b)
> [[alternative HTML version deleted]]
--
David Winsemius, MD
West Hartford, CT
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