What back-transform would you use for (1)? I use Sichel's theory, which produces prediction intervals for the lognormal back transform. Download any one of my...
2201
M. Nur Heriawan
mn_heriawan@...
Sep 8, 2005 8:39 am
Dear list, I am going to fit an ellipsoid model of anisotropy. The input are 4 ranges (scale parameters) and 4 main directions (0, 45, 90, 135 degree) from...
2202
Isobel Clark
drisobelclark@...
Sep 8, 2005 8:40 am
Rajni The nugget effect is the variance of the difference in values at very short distances. Your calculated nugget effect is an estimate of a true variance. ...
2203
Pierre Goovaerts
Goovaerts@...
Sep 8, 2005 8:40 am
Hi, In fact, as long as the weights are all positive and sum up to one, your interpolated probability will always be between 0 and 1; so you should be all...
2204
seba
sebastiano.trevisani@...
Sep 8, 2005 8:40 am
Dear Pierre and Gregorie Thank you for your help ..... Concluding (considering that natural neighbor method should be a convex and an exact interpolator) it...
2205
Gregoire Dubois
aigeostats
Sep 8, 2005 8:41 am
Ciao Sebastiano, I realized nobody replied to your question (sorry for have added confusion here). I don't see any objection in applying any interpolator to...
2206
Barrie Wells
Barrie.Wells@...
Sep 8, 2005 8:41 am
Do you have non-spatial control data? i.e. have you measured resistivity at single locations at a number of frequencies? This should help show you whether the...
2207
Gali
donq20vek@...
Sep 18, 2005 11:42 am
Dear list members, Question: At each observation point we do know an error of measurement. How can we incorporate this knowledge when krigging sparce...
2208
M.J. Abedini
abedini@...
Sep 18, 2005 11:42 am
Dear Reza I was away from my office for quite a while. After surfing my folder, I came across your enquiry. I found it helpful to share the following thoughts...
2209
Gerald van den Boogaart
boogaart@...
Sep 21, 2005 11:15 am
Dear Colin Badenhorst, The Lagrange Multipliers can be used to calculate the kriging error. Probably this is why they are stored by the software. Futhermore...
2210
Nicolas Gilardi
ngilardi@...
Sep 21, 2005 11:15 am
Hi Lise, The best way to sort this out is to try it :-) However, the nugget effect will certainly disappear from a variogram constructed on krigged data...
2211
Ted Harding
Ted.Harding@...
Sep 21, 2005 11:15 am
... In a constrained optimisation problem, e.g. minimising a function y(x, y, ...) with constraints expressed in the form g(x, y, ...) = c the value of the...
2212
Manuel Luis Ribeiro
manuloko@...
Sep 21, 2005 11:15 am
Hi Lise, If you run a stochastic simulation with a kriging algorithm you can reproduce the experimental variogram. But if you run a kriging estimation ...
2213
Gerald van den Boogaart
boogaart@...
Sep 21, 2005 11:16 am
Dear Gali Sirkis, If you know the variogram 2gamma of the values without error and the variance of the observation errors sigma^2_x, this can be used fairly...
2214
Isobel Clark
drisobelclark@...
Sep 21, 2005 11:16 am
Colin In most software the lagrangian multiplier is simply used to shortcut the calculation of the kriging variance. It is, basically, equal to the "average...
2215
Colin Badenhorst
CBadenhorst@...
Sep 21, 2005 11:16 am
Hi List, I've noticed that the latest version of my estimation software now stores the Lagrange multiplier (parameter) for each estimated block in my model. I...
2216
Lise Mentos
lmentos2@...
Sep 21, 2005 11:18 am
Hello, Could someone please settle a beer-bet with a classmate. He says that I should be able to reproduce the variogram model used for kriging a dataset by ...
2217
Colin Daly
Colin.Daly@...
Sep 21, 2005 11:36 am
RE: [ai-geostats] variograms of interpolated data Hi Lise If you did a Gaussian simulation - you should be able to reproduce the variogram (at least when it is...
2218
Colin Daly
Colin.Daly@...
Sep 28, 2005 9:37 am
RE: [ai-geostats] variograms of interpolated data Drink the beer Lise... the shape of the variogram will generally change. kriging is z^ = sum (lamdba_i * z_i)...
2219
Pierre Goovaerts
Goovaerts@...
Sep 28, 2005 9:37 am
Hi Koen, Although I am not a native speaker, you may want to check the few papers I have written on the computation and interpretation of indicator...
2220
Simone Sammartino
marenostrum@...
Sep 28, 2005 9:38 am
Dear Rajni
anyway if your aim is a quick spatial estimation there are some instruments that implement some specie of generic variogram by itself and return the...
2221
Manuel Luis Ribeiro
manuloko@...
Sep 28, 2005 9:38 am
Hello Rajni, To use Kriging methods you must have a variogram. If you don't want to use a variogram, you can use other spatial interpolators (check for IDW,...
2222
Rajni Gaur
rajni.geophy@...
Sep 28, 2005 9:38 am
Dear List, I have a querry regarding the variograms. Is it possible to estimate the data points without calculating the variogram? Either with kriging or...
2223
Njeri Wabiri
nwabiri@...
Sep 28, 2005 9:38 am
Hi Rajni, I thing literature on Geographiccaly weighted regression may be waht you are looking for. Best wishes, Njeri Wabiri UCT * By using the ai-geostats...
2224
Koen Hufkens
koen.hufkens@...
Sep 28, 2005 9:38 am
Hi list, Does anyone have any references to a clear description of the procedures to calculate and interpretate an indicator semivariogram? I know the ...
2225
Mahmut ÇETIN
mcet64@...
Sep 28, 2005 9:39 am
Hi Rajni, I could not understand your question clearly. If you have data at the sampled points what is the use of any estimation techniques? I think your aim...
2226
schattrj@...
Oct 16, 2005 7:06 am
Dear All List members Can anybody explain me smoothing and filtering ? their applications ? specially in point based feature and raster feature. With regards ...
2227
Isobel Clark
drisobelclark@...
Oct 16, 2005 7:06 am
David You seem to have two problems: (1) the Vulcan answer does not match your hand calculation for the same weights and values. (2) you have negative weights....
2228
john walter
jfwalter@...
Oct 16, 2005 7:06 am
Rajni, In simulations that I've done using data created with the same variogram but different CV's, increasing the CV scales the variogram sill and nugget ...
2229
Colin Badenhorst
CBadenhorst@...
Oct 16, 2005 7:06 am
Hi David, Wow. I don't think the problem is the negative weights. Which version are you using at the moment? Are you using tetramodelling by any chance? I...
