Negative Data Error with Decorana in Vegan
On 7/21/2010 12:43 AM, Jari Oksanen wrote:
On 21/07/10 00:37 AM, "Michele Tobias"<tobias.michele at gmail.com> wrote:
On 7/19/2010 5:49 PM, Gavin Simpson wrote:
On Mon, 2010-07-19 at 17:35 -0700, Michele Tobias wrote:
Thank you for your help, Gavin! Your suggestions helped me finally
figure out what the problem was. It turns out that my data frame had
the plot names (text) in the first column instead of plot names as the
row names for the data frame, so the error message didn't quite match
the problem: text where it shouldn't have been and not negative data.
Michele, I'm sure that there also were negative data entries because they were found and reported. However, I changed the order of tests in the devel version of vegan so that non-numeric data are detected and reported before checking negative data entries. This does not stop this kind of reports (and this was not the first one). When R says that you have non-numeric or negative data while you are "fairly sure" that you don't have them, the common rule is that you're wrong and R is right. Check your data to see that it is like you expect it to be. This is not an issue to argue with computers: they always win. Cheers, Jari Oksanen
Jari, Thank you for your help. I appreciate your willingness to address confusion. I did not mean to imply there was anything wrong with the code, only that something novel seems to be happening when certain data is imported into R that originated in an SQL database. Maybe there is something caused by the RSQL package that caused my problem. I will keep working with both packages and if I repeat the same issue, I will send you more information to see if you agree. Thanks again! 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