search for: variogram

Dear All, Is there anybody has the experience in using variogram(gstat) ? Please kindly give me some hints about the results. I used variogram() to build a semivariogram plot as: tr.var=variogram(Incr~1,loc=~X+Y,data=TRI2TU,width=5) then fir the variogram to get the parameters as: v.fit = fit.variogram(tr.var,vgm(0.5,"Exp",300,1)) v.fit model...

Dear all can you help me? i have this problem: i have a dataset in a text file in a matrix of 3 columns: x, y, z where x and y are the coordinates and Z are the mesurements. How can i do a variogram with R?

Dear Members, I am trying to fit a variogram model using fit.variogram function from the gstat package. The figure showing my experimental variogram can be seen here: https://i.stack.imgur.com/UZXw4.png My code line for this operation is: > c2.vgm.fit<-fit.variogram(c2.vgm.exp,vgm(nugget=0, psill=400,model="Exp",range =40000...

Hello, I have data at 10 locations, in each location there are time series (T=56). Question is: when I?m fitting variogram what happens with those measures in each location? Are they taken as repeated measures? It's very important for my to know this Thanks a lot

Greetings List, I'm having some trouble with the use of the names function in a formula. Below is an example of something that works (i.e first line), and the second line is the same formula which doesn't. I want to be able to reference the column of the dataC table so I can run the variogram iteratively with a loop. > v<-variogram(A1~1,loc=~x+y, dataC) > v<-variogram(names(dataC[3])~1,loc=~x+y, dataC) Error in model.frame(formula, rownames, variables, varnames, extras, extranames, : invalid variable type Where dataC looks like: x y A1 A2 A3 1...

Hi, I would know how to plot two variograms on a same graph. I can plot one by one but I would draw both on the same one. Is it possible? Do i need any special package? Thanks! Cordialement Damien Landais

...m a brand-new in R and geostatistic (SORRY, my background it?s in forestry) but I wish improve my skill for improve myself. I wish to develop a methodology to processing a large data-set of points (typical in LiDAR) but there is a problem with memory. I had created a subsample data-base but the semivariogram is periodic shape and I am not to able to try a fit the model. This is a maximum of two weeks of work (day bay day) SORRY. Is there a geostatistical user I am very happy to listen his suggests. Data format is X, Y and Z (height to create the DEM) in txt format I have this questions: 1. A...

When I try to run the example from Variogram with an lme object, I get an error (although summary works): R : Copyright 2005, The R Foundation for Statistical Computing Version 2.2.1 (2005-12-20 r36812) ISBN 3-900051-07-0 ... > fm1 <- lme(weight ~ Time * Diet, BodyWeight, ~ Time | Rat) Error: couldn't find function "lme&quo...

I wonder what is the default value for the argument 'cutoff' when not specified in the variogram.formula function of gstat. Computing variogram envelops within gstat, I am comparing the results obtained with variog in geoR and variogram in gstat, and it took me a while before understanding that the cutoff default value is not the maximum distance. Can Edzer tell us about it? All the best...

Hello R list, I need to compute empirical variograms using data from a large geographic area (~10^6 km2). Although I could not find a specific reference, I assume that both geoR and gstat calculate distances among data points assuming points are on a flat surface (using the Pythagorean Theorem). Because the location of my data is large and loc...

Dear Users, >From previous analysis (semi-variograms using package gstat), I found spatial autocorrelation in my dataset. The best fitted model to this spatial correlation structure is the Gaussian model (Spherical, Exponential, Linear tested and comparison done by Sum of Square errors). So I used corGaus function to define this spatial autocorrelat...

The following came up when Roger Bivand and I discussed R's name spaces and overlap in packages, in the bus to the field trip during StatGIS, last Tuesday: If two packages create the same class, say "variogram", and both are loaded, then using a method for an object of class "variogram" cannot discriminate between them and will call the method in the package loaded last. See example below. I know what is happening, but for average users this may be extremely confusing, especially when loa...

..., I am a remote sensing researcher currently studying the use of LiDAR data for quantifying tree height, in particular I would like to determine the sample size needed to capture and quantify canopy height variability. To do this I have employed the use of automap(), which automatically calculates variograms including reporting the range of the variogram. The program is easy to use and I have had much success with it. However, I have run into a slight problem. My analysis consists of 60 independent plots located in our study area and I wish to run the variogram analyses for each plot and then write t...

...ction gstat.cv: you simply pass a multivariable gstat object, and cross validation is done for the first variable in the object. Optionally, secondary variable records at locations coinciding with the validation locations are removed. 2. Class name changes Both gstat and geoR used the name "variogram" for -- highly incompatible -- objects that contain information about a variogram. This led to errors when calling plot() with a variogram object calculated from one, but plotted by the other package. I changed the class name into "gstatVariogram". The full list of class name changes...

...ction gstat.cv: you simply pass a multivariable gstat object, and cross validation is done for the first variable in the object. Optionally, secondary variable records at locations coinciding with the validation locations are removed. 2. Class name changes Both gstat and geoR used the name "variogram" for -- highly incompatible -- objects that contain information about a variogram. This led to errors when calling plot() with a variogram object calculated from one, but plotted by the other package. I changed the class name into "gstatVariogram". The full list of class name changes...

...to carry out an interpolation by krigeage. My goal is to obtain a chart of the distribution of precipitations/temperatures in Europe starting from 73 different stations (and, of course, distributed irregularly on the chart, where use of the krigeage). Here, I carried out this to test to obtain semivariogram spherical by groping: x<-ts(rnorm(73)) cs1<-corSpher(form=~x) y<-Variogram(cs1,2628) #2628 corresponding to the " distance" described in l' helps, that is to say the number of station* (the number of station -1) /2. But there does not go it misses apparently much d'...

...4 802050 3649150 8 0.529 2810 32 9996 9995 802050 3648950 6 0.529 2694 27 9997 9996 802450 3648750 8 0.529 2513 16 9998 9997 802950 3648450 6 0.529 2365 16 9999 9998 803550 3648450 10 0.529 2431 24 10000 9999 802950 3648150 6 0.529 2514 31 Here is my code for creating/computing the variogram coords <- coordinates(data) coords <- coords[,2:3] breaks <- seq(0, 10000, by=500) variogram <- variog(coords = coords, data = data$slp, option="bin", breaks=breaks) Here are the results (standard deviation in bold): > variogram $u [1] 250 750 1250 1750 2250 2750 3250...

Dear all, I am aiming to calculate variograms using variogram() from gstat. The problem is that some of my data-sets are very large (> 400000 points). Running the command takes some hours of time and does not give any error-message. Nevertheless the result seem not to be appropriate - the first few bins are ok (up to a distance of about...

Dear R Helpers I'm investigation the geostatistics tools in R and have found the package 'gstat', which looks to be useful four two dimensional data. However, I usually deal with three dimensional information. I would like to compute a 3D variogram map using the variogram tool but cannot seem to get it to recognise the third (z) dimension The data file reads ok and the spatial coordinates seem to be correctly applied (see result below) Dt<-read.table(DtFl,header = TRUE,sep = ",",na.strings = "-" ) > > > #set...

Hello group, For my PhD I'm working on a spatial sampling grid. I do have two data sets which I'd like to compare using cross-correlograms or cross-variograms. Is this an option in one of the R-packages? I've been searching the R-help archive and the available package-documentations, but I can't find how to do this. Thanks in advance, Ren?. _______________________________________ Ren? Eschen CABI Bioscience Switzerland Centre 1 Rue des Gr...