Displaying 20 results from an estimated 4000 matches similar to: ""predict"-fuction for metaMDS (vegan)"
2009 Sep 04
1
NA in cca (vegan)
Dear all,
I would like to calculate a cca (package vegan) with species and environmental data. One of these environmental variables is cos(EXPOSURE).
The problem: for flat releves there is no exposure. The value is missing and I can't call it 0 as 0 stands for east and west.
The cca does not run with missing values. What can I do to make vegan cca ignoring these missing values?
Thanks a lot,
2010 Apr 13
1
vegan (ordisurf): R² for smoothed surfaces
Dear r-helpers,
I just read in an article by Virtanen et al. (2006) where vegetation-environment relationships are studied by fitting smoothed surfaces on an NMDS ordination using GAMs (Wood 2000). The authors describe, that they used R? as goodness-of-fit statistic, which they compare to the R? of fitted vectors. Calculations were carried out using the package vegan (Oksanen).
I know that I can
2012 May 09
1
reception of (Vegan) envfit analysis by manuscript reviewers
I'm getting lots of grief from reviewers about figures generated with
the envfit function in the Vegan package. Has anyone else struggled to
effectively explain this analysis? If so, can you share any helpful
tips?
The most recent comment I've gotten back: "What this shows is which
NMDS axis separates the communities, not the relationship between the
edaphic factor and the
2011 May 10
3
metaMDS and envfit: Help reading output
Hello R experts,
I've used metaMDS to run NMDS on some fish abundance data, and am also working on correlating environmental data to the NMDS coordinates. I'm fairly new to metaMDS and NMDS in general, so I have what are probably some very basic questions. My fish abundance data consists of 66 sites for which up to 20 species of fish were identified and counted. I ran metaMDS on this data
2012 Jul 27
1
labeling loading vectors in vegan
Hello,
I am using vegan to do an NMDS plot and I would like to suppress the labels
for the loading vectors. Is this possible? Alternatively, how can I avoid
overlap?
Many thanks for the help.
Example code:
#perform NMDS using metaMDS() function
spe.nmds<-metaMDS(data, distance='bray',k=2 , engine = "isoMDS",
autotransform=F, trymax=1000)
#calculate the loading (i.e.,
2011 Sep 23
1
Envfit, inconsistant result?
Hi R-experts,
I am using the envfit function over an ordination of floristic data.
The problem is that every time that I run it changes the results. Sometimes
dramatically, selecting variables that the first time were not significant.
I do not get what could be the problem or if is normal given the
permutations are different.
# the NMDS ordination
gap_flor_NMDS_chord <- metaMDS(gaps_flor,
2009 Oct 06
1
previous.best in metaMDS
Dear R-community, dear Jari Oksanen!
I use metaMDS (package vegan) to calculate NMDS.
In a lot of papers I read that it is recommended to use previous best solutions as a new starting configuration to get better results and to avoid local minima.
On the help page I found that a previous.best-command is already implemented in metaMDS:
metaMDS(comm, distance = "bray", ...,plot = FALSE,
2011 Mar 28
1
ordination in vegan
Hi all,
I have site data with plant species cover and am looking for trends. I'm
kind of new to this, but have done lots of reading and can't find an answer.
I tried decorana (I know it's been replaced by ca.) and see a trend, but I'm
not sure what it means. Is there a way to get the loadings/eigenvectors of
the axes (like in PCA)? Is there a way to do this with rda() too? How
2007 Aug 24
1
Adding new points to a metaMDS ordination ("vegan" pkg)
Hi, I've been using R for a while now but I've got a problem with
metaMDS (in the vegan package) that I can't quite figure out.
I have a set of proportion data (from 0-1, rows sum to 1) that I apply
metaMDS to using the command:
nMDS.set=metaMDS(sqrt(test.set),distance="euclidean",k=3,zerodist="add",autotransform=FALSE)
I am using a squared-chord distance
2014 Sep 13
1
vegan moved to GitHub and vegan 2.2-0 is coming (are you ready?)
Dear vegan team,
Vegan development happens now completely in github. R-Forge repository is no more in sync with github. I tried to commit all github changes to R-Forge, but a week ago I got a conflict in file and I haven't had time to resolve that conflict. You can follow vegan development and vegan discussion also without signing to github. The system seems to be completely open and does not
2009 Oct 14
2
metaMDS NMDS: use of alternative distances?
Dear r-helpers!
How can I integrate other distances (in the form of a dist object) into function metaMDS? The problem: metaMDS needs the original data.frame for the calculation and only the default distances of function vegdist are allowed.
Any suggestions are greatly appreciated!
Thank you,
Kim
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2012 Dec 29
2
Error in plot.envfit(ef, p.max = 0.1) : (subscript) logical subscript too long
Hello there,
I'm trying to plot vectors with p<0.1 in a NMDS ordination plot using p.max. Below the scripts I'm using. I guess I'm missing something! could you please give me a hand?
species<-metaMDS(species_matrix)ef<-envfit(species,environmentaldata_file,permu=999,na.rm=TRUE)efplot(species, dis="sites")plot(ef,p.max=0.1)
Error in plot.envfit(ef, p.max = 0.1) :
2008 Apr 14
1
Vegan R^2 and tau values for metaMDS
I am using the function metaMDS with jaccard distances to ordinate a
set of constituent by site matrix. I can post this data if it would
be helpful, but it is large to include in an email. I can also
provide reproducable code if necessary. I would like to get an R^2
value for the axes of the ordination configuration that I get with
metaMDS in the vegan package is there a way to do this- is it
2012 May 10
1
envfit output (vegan package) - not sure what it means
I'm pretty new to R and would appreciate some help interpreting the output of
a function that was recommended to me.
I've used the *envfit *function in the vegan package to plot vectors of four
climate variables onto a species matrix ordination. The output indicates
that only a single variable (mean_temp) is significant:
***VECTORS
NMDS1 NMDS2 r2
2009 Jan 21
1
vegan metaMDS
Hi,
I'm trying to use metaMDS with a dissimilarity matrix of angles, not
Bray-Curtis, and I wanted to know if there is an in-built function to
produce a plot of stress values against dimensions, that could be used to
determine the 'true' dimension of the solution. The number of objects is
only a lowly 8 so any solution higher than 2-dimensional is not likely to be
interpretable,
2009 May 27
1
vegan metaMDS question
The design decision in metaMDS says that it uses:
Minchin, P.R. (1987) An evaluation of relative robustness of
techniques for ecological ordinations. Vegetatio 71, 145-156.
This is the paper that I found by the same name. Is this the correct reference?
Minchin, Peter R.1987. An Evaluation of the Relative Robustness of
Techniques for Ecological Ordination. Vegetatio. Vol. 69, No. 1/3:
89-107.
2008 Nov 12
1
gam help (really a vegan question)
What does Generalized Cross Validation score mean. I preform and
ordisurf on an ordination (nmds) with an environmental variable. I am
trying to figure out "how well" the environmental varibles
predict/explain the sites placements in species space. Any help would
be greatly appreciated. Any pointers to literature... would be
welcome.
thanks in advance,
--
Stephen Sefick
Research
2007 Nov 14
1
label plotting on nmds diagram
Hi,
I'm using nmds command (library vegan) to analyze some fishing data.
I'd like to plot not only points, but also the names of species and stations in
a specified position.
I used the command
text(nmds$points[,1], nmds $points[,2],labels=row.names(nmds
$points),pos=3,cex=0.5)
But the labels are sometimes overlapped.
Is there any way to use identify, or a similar command, to plot the
2010 Apr 05
4
NMDS Ordination Graphics Problem
Dr. Stevens,
Hi, my name is Trey Scott, and I'm a grad student of Brian McCarthy's. He
referred me to you because of your expertise in handling complex R problems.
We were hoping you could help us solve a nagging problem that is prohibiting
me from producing graphicl output.
Here is a simple mock-up of the matrix I'm using
a b c d e f
1i 1 4
2009 Nov 05
1
plot.envfit/move labels
Dear r-helpers!
Jan Thiele asked r-help-list in february, but I could not find an answer to his question. I have the same problem:
While preparing figures of 'envfit' plots with vegan for publication, I ran into a layout problem, that I found no solution for in the literature or the help archive:
The labels of the vectors that indicate correlations of environental variables sometimes