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Questions tagged [variogram]

A function describing the degree of spatial dependence of a spatial random field or stochastic process

-1
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1answer
38 views

Does the sampling design affect the variogram and mapping? [closed]

I am not sure if this is the right place to ask the question, but I don't know where to ask. So please excuse me if not so. I am considering two sampling strategies, the first is locating samples on ...
0
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1answer
59 views

Which is the model semivariogram for binary data?

I have a binary data (1,0) to calculate spatial distribution of soil bacteria. I have to use indicator kriging (presence/absence) and fitting model of semivariogram. Then, which is the model ...
1
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0answers
94 views

Error in calculating covariance matrix and fitting variogram model

When constructing variogram model, usually the spatial points are given, and we build a variogram model and conduct parameter estimation. But here in my question the points are not given while ...
0
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1answer
70 views

gstat variogram errors

I am at a complete loss on what I am doing wrong here. I am trying to build a variogram. No matter what i do i get errors. My Data: id lon lat datetime ...
5
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1answer
112 views

Cokriging: zero distance cross-semivariance in undersampled cases [gstat error]

Trying to cokrige two variables that are not perfectly colocated (one has sparser measurements than the other), I faced an issue that I'll illustrate with the following MRE. With the meuse dataset, ...
0
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0answers
51 views

Cokriging, Zero distance semivariance in cross-variogram error

Trying cokriging with simulated data, I faced a problem that did not seem one in the demo(cokriging) with the meuse dataset: I can't use fit.lmc() default but need to specify fit.method=1 as the ...
2
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0answers
134 views

Empirical variogram plot in QGIS

I am trying to do kriging on mortality rates using QGIS (I have version 3.0 but I downloaded the 2.18.20 to be able to follow the web documentation and most of the answers here). From what I have ...
4
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1answer
203 views

Preparing dataset to perform co-kriging in R gstat?

This is the first time I'm using co-kriging in gstat. My problem is that I'm not sure how to prepare the data frame to supply to co-kriging when the variable of interest and auxiliary variables are ...
1
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0answers
16 views

Kriging with a non-uniform (not space filling with concentrated data in certain regions) sampling design?

I am using Kriging for optimization where local searches are often carried out. However, because of these local searches my sample design becomes poor and my Kriging prediction as well as variance ...
1
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2answers
691 views

How to find initial values for fit.variogram

I wish to estimate a variogram for spatially distributed price data in Tanzania. I'm new to both spatial statistics and gstat, and have a couple questions. (1) I can SEE spatial patterns in price, ...
5
votes
2answers
326 views

How to make a prediction in Kriging using a semivariogram?

In Esri's documentation on how to make a prediction in Kriging, I couldn't figure out the linkage between the semivariograms and the prediction process from reading the description therein: After ...
1
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1answer
137 views

semivariogramm - manual calculation

I have a graph with some data points: From these data points I have created a table and calculated the Euclidean distance for each combination. Now, I would like to calculate the semi variances ...
3
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1answer
169 views

Error in fit.variogram.gls method of gstat package in R

I was trying to fit the variogram parameters of an empirical variogram using GLS (Generalized Least Squares) fitting method. I used the 'fit.variogram.gls' method of the 'gstat' package in R. I tried ...
1
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1answer
144 views

Statistically comparing two spatially congruent continuous rasters?

First: Rasters are the same spatial resolution & extent and contain the same kind of information. Each pixel contains a probability value from 0-1. Sounds simple to compare. Conventional wisdom ...
1
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0answers
79 views

How to obtain nugget parameter from fit.variogram in gstat? [closed]

I have the following code where I fit a variogram using gstat. vA = variogram(dep_var~elevation=x+y, data, cressie=TRUE) vmodel = vgm("Sph") vB = fit.variogram(vA,vmodel) How can I get the nugget ...
2
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0answers
150 views

Fit variogram doesn't work [closed]

I have a variogram and i'm trying to fit an exponential variogram Variogram and i try to estimate the parameter of this variogram through the data: vk=variogram(z~1, data=data) nugget_ini=....
1
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1answer
1k views

Fit Variogram Iteration Warning

I would like to perform kriging using a variable call "Secchi.Disk" from a data set I have. However, when fitting the variogram I get the following warming message Warning message: In fit.variogram(v,...
2
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0answers
155 views

What should be different variogram model in kriging [closed]

In ordinary kriging algorithm in QGIS (Saga algorithms provided in QGIS) there is field for Variogram model which by default is given as 'a + b * x' what does it signify and what are other options to ...
2
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1answer
327 views

How to make ordinary krigging with a spherical variogram in SAGA GIS?

I have a very special map to make: it's a sea bird density map. To do this, I interpolate the observation points with ordinary kriging with a variogram. As I've read, the variogram must be of "...
1
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0answers
300 views

Poor fit of variograms in spatial GLS models

I run into some problems when investigating correlation structures in spatial GLS models, precisely that fitted variogram does not fit residuals. Template data can be downloaded here: http://...
2
votes
1answer
558 views

Adjust text font size in plotting autofitvariogram in R?

It should be quite simple to adjust the font size in plotting the outcome ofautofitVariogram using the automap package. The text fonts for the number of pairs are too big; the text fonts for the model,...
1
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1answer
147 views

Kriging predictions for presence only data with Maxent

I was doing some geostatistical analysis (variogram+kriging) for a "presence only" type data in a species distribution modeling context. Since, we know that when estimating the (empirical) variogram, ...
2
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1answer
2k views

R 'gstat - Warning: singular model in variogram fit

I am trying to perform a kriging interpolation. But when it comes to the point when i want to fit the variogram to the model I get the following warning: In fit.variogram(vario, vgm("Sph")) : singular ...
1
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2answers
544 views

How do I get the fitted values and/or residuals in fit.variogram() function of gstat package of R?

I am trying to do some diagnostics after fitting a variogram model to my empirical variogram using fit.variogram() function in gstat package of R. I need to get a hold of residuals and the fitted ...
3
votes
1answer
2k views

Variogram model - SAGA on QGIS Processing

QGIS 2.14 (Win) comes with SAGA 2.12, which Ordinary Kriging supports 6 variogram model options. However, if I run SAGA Ordinary Kriging from QGIS Processing Toolbox, there is no drop down menu. Only ...
1
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1answer
210 views

Fixing error in if (any(model$range < 0)) statement when fitting variogram in R?

I am using R and trying to fit a variogram model that I created: mod <- vgm(psill = var(newdfNoNAs$yield_cleaned),range= NA, model = 'Sph',nugget = 0) And I used fit_reml <- fit.variogram....
2
votes
1answer
2k views

Ignoring NA values when computing variogram in R?

I am trying to compute a variogram with the R gstat package: > variogram(yield_cleaned~1, data= newdf) but it turns out: Error in .local(obj, ...) : NA values in coordinates My dataset has ...
4
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1answer
377 views

Exponential function variogram sill values

I am using gstat package for deriving a variogram using exponential model. My R code goes like this: g <- gstat(id= "HV",formula=HV~X+Y,data=vari) vari.var <- variogram(g) vari.var plot(vari....
4
votes
1answer
461 views

Goodness of fit of variogram model using geoR

How can I find a measure of goodness of fit (let's say an R2) of a model fitted to a variogram by the function variofit using the geoR package? The only value I have is the "minimised weighted sum of ...
1
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0answers
167 views

Creating pooled variogram in gstat

I am currently using gstat to perform ordinary kriging on daily fields of some variable - that is a new variogram is fit for every daily set of observations. I would like to compare this with ...
1
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0answers
429 views

Problem in Variogram Plot [closed]

I tried to plot Variogram by this code from gstat packages: v <- variogram(log(zinc) ~ 1, meuse) plot(v) and here is the output: But I want to add line to point (draw variogram line). How I ...
1
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0answers
138 views

Interpreting variogram: negative values beyond model sill?

The negative values mean that there is negative autocorrelation at some far distance, like a repulsion. How would this affect assessment of the range? (This is just for learning the scale of a ...
0
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1answer
177 views

semi variogram analysis for buidings in raster dem with penta spherical model

I am carrying out semi-variogram analysis in arcgis using geostatistical tool on a DEM. the plot gives the semi variance and lag distance. I want to know at what elevation of DEM the sill value is ...
1
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1answer
343 views

variogramST in R

I've been following the tutorial in this site to compute the spatio-temporal variogram in R. The result from variogramST is the object called var, and it contains several NAs for np, dist, and gamma, ...
10
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1answer
877 views

Interpreting semivariogram with high nugget effect?

I made a semivariogram in R using package gstat, variogram() function. I want to see if there is spatial autocorrelation in the residuals of my model (species abundance as a function of habitat, ...
3
votes
1answer
114 views

Variogram for data along linear routes

I have a dataset of some measurements along a bus route (image below). The purpose of my study is to be able to detect the values at any location along the route using Kriging interpolation. I have ...
2
votes
1answer
709 views

Getting range value from exponential variogram model

I am using vgm() from the gstat library in R: variogr <-vgm(sill,"Exp",range=range,nugget=0) output <-krige(...,model=variogr) As you can see I'm using fixed psill and range values. Before ...
3
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0answers
167 views

Visualize smoke dispersion by interpolating point data [closed]

During the last weeks, I am trying to develop an application within my current working project, which aims to simulate smoke dispersion of fire incidents. Software used: ArcGIS for Desktop/Server (...
2
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1answer
153 views

weighting scheme of gstat for fitting models to variograms

I use R and the gstat package to construct variograms of temperature, and I would like to ask If anyone knows what weighting scheme does the gstat package use to fit a model to the sample variogram?