Yes, indeed! I believe I should integrate differences of min of both functions,
no? I'm not quite sure how this should be done in R therefore I was wondering
if there are some build in functions that do this job already. If not I would
appreciate any help of how should it be done otherwise.
Toy example of data is here:
a <- matrix(runif(30))
b <- matrix(runif(30))
I tried to calculate this overlap with "Istat" function but am not sure that it
does the job right! This is the example:
library(SDMTools)
a <- matrix(runif(30))
b <- matrix(runif(30))
Istat(a,b)
Many thanks for your response, David!
Ana
>________________________________
>From: David Winsemius <dwinsem...@comcast.net>
>To: Ana Kolar <annako...@yahoo.com>
>Cc: R <r-help@r-project.org>
>Sent: Monday, 18 July 2011, 15:45
>Subject: Re: [R] SDMTools package - calculating overlap?
>
>
>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
>
>
>
>
[[alternative HTML version deleted]]
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