[R-sig-eco] Can Gravy's HOF Ignore NAs?
Michele Tobias
tobias.michele at gmail.com
Fri Mar 4 23:40:44 CET 2011
Hello,
I'm building species response curves for several species (one curve for
each species) using the percent cover measured at twenty points at
increasing distance from a trail's edge (each successive point is 5
meters from the last). This data was collected at several locations,
and each location did not have all of the species present. Because of
this, my dataframe has NA values when a species did not occur at a
particular site. I can change the NAs to zeros, but zero has a
different meaning from NA. Is there a way to have the HOF function in
the gravy package ignore the NAs? I tried running the data with the NAs
left alone, and I get an error message. The function works after I
change the NAs to zeros but the extra zeros that were NAs seem to be
affecting the output. I've typed out an example similar to the table
I'm working with below, in case that helps:
Example table:
Location Species 1 Species 2 Species 3
Site 1 Point 1 10 5 15
Site 1 Point 2 15 10 0
Site 2 Point 1 5 20 NA
Site 2 Point 2 20 10 NA
I tried looking at the source code for the HOF function to answer my own
question, but I'm not familiar with the language it was written in.
Thank you in advance for your help! I'm very happy with the results
I've gotten so far and I'm looking forward to refining what I have.
best,
Michele
--
Michele Tobias
PhD Candidate
Geography Graduate Group
University of California, Davis
mmtobias at ucdavis.edu
http://ggg.ucdavis.edu/student/michele-m-tobias
http://ucdavis.academia.edu/MicheleTobias
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