Displaying 20 results from an estimated 1000 matches similar to: "spatial markov chain methods"
2013 Nov 24
1
create a new dataframe with intervals and computing a weighted average for each of its rows
I need you help with this problem, I have a data-frame like this:
BHID=c(43,43,43,43,44,44,44,44,44) FROM=c(50.9,46.7,44.2,43.1,52.3,51.9,49.3,46.2,42.38) TO=c(46.7,44.2,43.1,40.9,51.9,49.3,46.2,42.38,36.3) AR=c(45,46,0.0,38.45,50.05,22.9,0,25,9) DF<-data.frame(BHID,FROM,TO,VALUE) #add the length DF$LENGTH=DF$FROM-DF$TO
where:
+ BHID: is the borehole
2012 Jul 31
2
Spatial regression
Dear list members,
I have a large dataset with point data. Each data point has X, Y, number of
species present and values for one single explanatory variable. Each point
was generated from a polygon grid shapefile and they are at equal
distances.
I conducted GLS analyses introducing variance structures and correlation
structures to improve the model.
I plotted variograms before and after adding
2011 Mar 25
1
spatial stats - geoR - variogram - standard deviation
Hello,
I am attempting to get the standard deviation in multiple distance bins in
my spatial data.
It appears as though the 'variog' command in the geoR package will do the
trick, as one of the outputs from 'variog' is 'variog$sd', which,
according to the manual, is the "standard deviation of the values in each
bin".
However, when I run this command, the
2008 Apr 01
1
spatial cross-correlation
Hi;
I cannot find in the R html documentation a way to evaluate
cross-correlation in 2D data sets.
I would like to evaluate cross-correlation in a series of moving windows
between two maps.
i,e, specify several windows inside the complete 2D spatial matrixes and
for each one ofthese windows evaluate the 2D cross-correlation (commonly
conducted in the spectral domain).
Thanks in advance and best
2010 Nov 07
0
multiple regression analysis
Hi all,
This is more a help on ideas that on actuall R code. Those of you which are geologist or work with boreholes woudl understand that i would like to achieve.
I'll tr to explain as good as I can...so here it goes..
I have around 1000 geomechanical (geological) borehole logs in a database. The logs contain staial info, lithology and some laboratory data. My initial goal is
2003 Jul 31
1
spatial statistics vs. spatial econometrics
Dear R users,
I am putting together reading and resources lists for spatial statistics and spatial econometrics and am looking for some pointers from more experienced practitioners.
In particular, I find two "camps" in spatial modelling, and am wondering which approach is better suitied to which situation.
The first camp is along the lines of Venables and Ripley's Chapter 14
2005 Nov 09
2
Variograms and large distances
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 located near the
pole, assuming that latitude and
2009 Jun 10
2
plot two variograms on a same graph
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
2004 Sep 16
1
geoR/variog4() not returning all directions
Mac OS 10.3.5, R 2.0.0
latest version of geoR
I have an incomplete 5 x 20 spatial array of samples (60 out of 100
possible locations) for which I would like to calculate directional
variograms using variog4(). Unfortunately, I can't get it to return all
4 directions. It returns variograms for 45, 90, and 135 degrees,
omitting 0 degrees (pi/4, pi/2, 3pi/4, omitting 0). If I specify 0
2004 Oct 05
1
Bug in optim - way to solve problem?
Hi,
I want to automatically fit variograms to a large number of different
sample data sets, and call the funtion "likfit" (in package geoR) from
within a for-loop. "likfit" does again call "optim". After ssuccessfully
fitting variograms to some of the data sets, the procedure crashes and I
get the error message:
Error in optim(par = ini, fn = negloglik.GRF,
2011 Jan 03
1
Modules for using geostatistics for image classification
Hello everyone!
I am using GRASS with spgrass6 for my work. I will be using variograms in
the process of landsat image classification. I am quite ok with GRASS but am
finding R really tough. I understand that spgrass6 is a link between GRASS
and R which can read and write raster/vector layers. Out of really many
packages in R, for generating variograms out of landsat images which
packages of R
2009 Sep 08
1
gstat---2 basic plot questions
Hi all--
I'm new to R, statistics and programming, so sorry if this is a really basic
question!
I have plotted a directional variogram, and I want to
a. overlay the omni-directional line over each directional panel
b. display the directional variograms in a single panel with a legend that
associated each line to each degree measurement.
The line I'm using is
2001 Feb 28
1
re: Spatial stats: R vs. Splus
Hello,
Could someone tell me whether the spatial statistics module of
Splus is worth the rather high price, or whether one could (with
reasonable effort) carry out the same things using R and some of
its contributed packages.
Although we do have Splus (Windows and Unix), we definitely prefer
to use R whenever feasible (both for research and teaching).
Thanks for developing a superb
2004 Mar 16
2
graphical interface
Dear R users,,
I'm having difficulties when i use the gstat extensions in R
especially with the graphical interface, as the
variograms plots are depicted with gray background and cyan points for the number of pairs, Consequently the fitted variogram
is drawn in cyan,
How can i change that so i could have, white background and
black lines for the fitted variogram, for the complete plot.
2010 Oct 29
2
doubt in climate variability analysis in R!
Hello all,
I am trying to use "clim.pact" package for my work, but since this is the beginning for me to use gridded datasets in "R", I am having some trouble.
I want to do seasonal analyses like trends, anomalies, variograms, EOF and probably kriging too to downscale my 1 degree gridded data to 0.5. So, as a first step, I compiled my entire dataset (with 25
2006 Nov 27
2
[R-sig-Geo] plot() and Jpeg() increase font size and resolution
Thanks to Edzer and Roger,
I can now plot with increased font sizes. However, jpeg still does not
reproduce these, nor does it show up in high quality. What I would like
to do is produce some highresolution jpegs.
Any help would be appreciated
Thanx
Herry
R2.4 on Mandriva 10.2 linux.
Dr Alexander Herr
Spatial and statistical analyst
CSIRO, Sustainable Ecosystems
Davies Laboratory,
University
2010 Jun 25
1
variograms and kriging
Hello
Trying to develop variograms and kriged surfaces from a point file. Here is
what I've done so far.
library(gstat) # also loads library(sp)
library(lattice)
soilpts$x <- soilpts$UTM_X
soilpts$y <- soilpts$UTM_Y
soil.dat <- subset(soilpts, select=c(x, y, Area, BulkDensity, LOI, TP, TN,
TC, Total_Mg))
dim(soil.dat)
[1] 1292 7
coordinates(soil.dat) <- ~ x+y
2007 Jun 06
1
Metropolis-Hastings Markov Chain Monte Carlo in Spatstat
I'm testing some different formulations of pairwise interaction point processes
in Spatstat (version 1.11-6) using R 2.5.0 on a Windows platform and I wish to
simulate them using the Metropolis-Hastings algorithm implemented with Spatstat.
Spatstat utilizes Fortran77 code with the preprocessor RatFor to do the
Metropolis-Hastings MCMC, but the Makefile is more complicated than any I have
2002 Dec 17
2
Cross-correlograms or cross-variograms in R?
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?.
2008 Jun 11
2
MLE Estimation of Gamma Distribution Parameters for data with 'zeros'
Greetings, all
I am having difficulty getting the fitdistr() function to return without
an error on my data. Specifically, what I'm trying to do is get a
parameter estimation for fracture intensity data in a well / borehole.
Lower bound is 0 (no fractures in the selected data interval), and upper
bound is ~ 10 - 50, depending on what scale you are conducting the
analysis on.
I read in the