Re: [R-sig-eco] [EXTERNAL] Time to Independence in R

2021-03-03 Thread Philippi, Tom
Manuel-- I apologize in advance for not answering the exact question you ask about packages. [It is included in some geostatistics packages in terms of semivariance, nugget, sill, etc.] In ecological data, time to independence is very scale dependent. There's autocorrelation at scales of

Re: [R-sig-eco] Ecological datasets for teaching statistics

2020-06-18 Thread Philippi, Tom
Many ecological journals either encourage or require that the dataset behind a paper be submitted to a repository such as dryad, or included as an electronic appendix. Even if your university does not have institutional subscription to all journals, some journals like Ecosphere are

Re: [R-sig-eco] [EXTERNAL] Re: trasformation of matrix for iNEXT extrapolation interpolation of Hill's numbers

2019-06-20 Thread Philippi, Tom
Or, if the component matrices need to be numeric with species names as row names and sites as column names, Dave Roberts' labdsv package has matrify() that does that and fills in the unseen combinations with 0s as opposed to NAs. Converting {site, taxon, abundance} triplets to matrix form is a

Re: [R-sig-eco] [EXTERNAL] Producing images of Plant leaves in R

2019-06-11 Thread Philippi, Tom
Eric-- If you don't care about "leaf-like" shape, you have 6 X,Y points defined plus a pair of points at the maximum width at some undefined distance from the apex. Assuming bilateral symmetry, and assuming that the maximum width is at 50% from apex to base, you have 5 points {0,0,

Re: [R-sig-eco] [EXTERNAL] Re: Query

2019-05-30 Thread Philippi, Tom
Bruce-- You don't specify if you want the intersected polygons: 1 record for each polygon intersection of species rangemap and habitat polygon, or just a list of which habitat type polygons are at least partially within the species' rangemap polygons. The former is much slower but can give you

[R-sig-eco] Fwd: [EXTERNAL] Which R package for Second-Stage nMDS ?

2019-03-22 Thread Philippi, Tom
Pierre-- That's actually an easy question. Look at the vegan package https://cran.r-project.org/web/packages/vegan/index.html. It has functions for various dissimilarity & distance metrics (and can use distance matrices from other packages such as ecodist), MDS and allied processes, anosim and

Re: [R-sig-eco] How to extract values from contiguous raster cells that ate not touched by SpatialLines?

2017-08-18 Thread Philippi, Tom
Andre-- I'm not completely clear on what you are trying to do. My best guess interpretation of "my raster sometimes goes from one to several contiguous cells in all directions" is that you have a raster that you are aggregating into blobs of contiguous cells based on values in one layer. You

Re: [R-sig-eco] Package to analyse population time series (trend analysis)

2016-10-19 Thread Philippi, Tom
Manuel-- The proper package depends entirely on what your data are: how many sites you collect counts for, whether those sites are a probability sample over an area or the only locations you are making inferences about (e.g., census counts), whether those counts have Poisson error, overdispersion

Re: [R-sig-eco] NMDS axes scores

2016-01-17 Thread Philippi, Tom
Conny-- Note that Jari's surface fitting is using ordination scores on the right-hand predictor size of the formula, with some z as the response. If you need something about species composition as your _response_ variable in a linear model (e.g., with time, disturbance type, and treatment as

Re: [R-sig-eco] automating ações

2015-09-15 Thread Philippi, Tom
Katia-- Your attached script didn't come through. as attachments are stripped by the mailing list. However, I can give you 2 generic answers. First, if your vector of species names is called SpList, and your data are in a big SpatialPointsDataFrame spdf for (SP in SpList) { spSP <-

Re: [R-sig-eco] T50 or ED50 for count data

2015-07-24 Thread Philippi, Tom
in the package survival. Warm regards, Mehdi On Fri, Jul 24, 2015 at 4:11 AM, Philippi, Tom tom_phili...@nps.gov wrote: Mehdi-- Based on the example datasets germination and chickweed, drc would work with you using the final count of emergence as the number of seeds at risk of germinating. If you

Re: [R-sig-eco] T50 or ED50 for count data

2015-07-23 Thread Philippi, Tom
Mehdi-- Based on the example datasets germination and chickweed, drc would work with you using the final count of emergence as the number of seeds at risk of germinating. If you get a satisfactory fit from one of the 6 or so function forms it supports for dose-response, you may be fine. [I have

Re: [R-sig-eco] Ancova Plot R

2015-03-16 Thread Philippi, Tom
Luis-- I assume that especie is a factor, else it would be multiple regression. You do not give much information on what you want your graph to look like. If you want the linear regression line for each especie, with confidence bands around those lines, you can use ggplot2 (untested code):

Re: [R-sig-eco] Multivariate quasi-bionomial analysis of proportion data?

2015-02-09 Thread Philippi, Tom
Amanda-- I'm not sure I would be convinced by you analyses, as I don't think your statistical model corresponds to your sampling or data generating process. But, I'd need to know more information about the response design (data collection) to make any suggestions. For binomial or quasi-, you

Re: [R-sig-eco] Can I weight LS means estimates by elevation in lme4/lmerTest packages?

2014-11-28 Thread Philippi, Tom
Matthew-- Do you get what you want in terms of estimated effect of ecosystem type by dropping Elevation from your model? That difference would include the component of the response to the difference in mean elevation. If not, from a pure parameter estimation perspective, if your simulated data

Re: [R-sig-eco] Using NADA and rkt for seasonal Mann Kendall tests for censored datasets

2014-07-24 Thread Philippi, Tom
Tim-- When I had decreasing MDL over a monitoring period, I looked at the distribution of the values collected under the later, lower MDL (MDL2) that were MDL1 (including BDL2), then used that distribution (estimated via kerneling) to simulate/impute values under the earlier MDL1. In my

Re: [R-sig-eco] Assigning Rank to Temporal Data

2014-03-12 Thread Philippi, Tom
In order to glue tide height (or tide current) onto each fish position observation: 1: Convert dates times to POSIXct (do it all in GMT to avoid DST issues!). 2: Consider using NOAA tide data, available as 6 minute interval time series http://tidesandcurrents.noaa.gov/api/ . Luke Miller has

Re: [R-sig-eco] function to extract climatic variables from shape file - error

2013-09-18 Thread Philippi, Tom
Maria-- I believe that your problem is with the line: s1-readShapePoly(shapes[i], verbose=T) It may be as simple as removing the quote marks: s1-readShapePoly(shapes[i], verbose=T) as shapes is a vector of character. However, I use rgdal::readOGR() to read shapefiles, so your mileage may vary,

Re: [R-sig-eco] merge multi part polygons

2013-09-13 Thread Philippi, Tom
Maria-- I believe that your NAs from the extract are because those polygons do not cover at least 1 center point of a pixel in your bioclim rasters. One solution is to use small=TRUE in your call to extract: see ?extract for more information. Another would be to pull the bioclim data with

Re: [R-sig-eco] Any R packages equivalent to Fragstats?

2013-04-17 Thread Philippi, Tom
I would start with SDMTools On Wed, Apr 17, 2013 at 10:22 AM, Bruce Miller batsnc...@gmail.com wrote: Hi all, Any/*R*/ packages that include the equivalent of FRAGSTATS for fragmentation indices? Tnx Bruce [[alternative HTML version deleted]]

Re: [R-sig-eco] quantifying directed dependence of environmental factors

2013-03-07 Thread Philippi, Tom
Jay-- I'm not sure how one would combine SEM / graphical models with compositional dissimilarity as a response. You might be able to fit a series of models in adonis() or capscale(), comparing just direct factors to direct + intermediate, etc.. I don't have any good ideas on how you might test

Re: [R-sig-eco] Zuur / Pinierho / Faraway

2012-11-30 Thread Philippi, Tom
At least some errata at: http://www.maths.bath.ac.uk/~jjf23/ELM/ http://www.maths.bath.ac.uk/~jjf23/ELM/errata.html Tom 2 On Fri, Nov 30, 2012 at 10:47 AM, Dave Roberts dvr...@ecology.msu.montana.edu wrote: Philip, IS there an online errata,or do you just have to be smart and diligent?

Re: [R-sig-eco] Zuur or Pinheiro Bates

2012-11-28 Thread Philippi, Tom
I would also recommend considering Faraway (2006) Extending the linear model with R and the draft chapters of Doug bates' lme4 book: http://lme4.r-forge.r-project.org/book/ The choice between Pinheiro Bates, Zuur, and Faraway is part style and part specific applications of mixed models: I need