Latest Contributions by SimonHarper

‎08-29-2019

Hi Eric, That response was very useful - thanks for your explanation.

‎08-28-2019

Hey Eric, Thanks for the reply again. One question - why do you need to have predicted values for the new points? Sorry, sounds like a silly question but I thought the kriging standard error is independent of the measured value. I'm noticing that with some of these kriging methods the value makes a difference. Thanks again, Simon

‎08-28-2019

The method I'm applying doesn't work with the results using Bayesian Kriging either i.e. my kriging std errors increase as my network densifies. Maybe the method I'm applying is wrong?

‎08-28-2019

One more thing. I'm guessing the method that I am using is very much similar to the approach of the Densify Sample Network Tool. That is, the DSN tool must add new sites at unknown locations and recalculate the standard error before choosing the next site. I'm assuming they don't face the problem I originally accounted?

‎08-28-2019

Hi Eric, Thanks for the suggestions. I tried a default simple kriging method with a normal score transformation and the concept worked perfectly i.e. the average standard error reduced as my network increased in size. I also further tested my method by evaluating the kriging error on my original data set by: a) using measured values and b) using my location column as the measured field. This demonstrated the standard error was not affected by the measured value. My original test was with Ordinary Kriging, log transformation and a second order trend removal. I will try the Bayesian kriging model to see what happens. To estimate my average kriging error I am using a dense sample array of wells over my study error to extract the std errors using the GA to points function. I suppose I could possible use a raster to do something similar. Regards, Simon

‎08-27-2019

Hi there, I was just wondering whether there is an online depository where developers might upload some of there custom toolboxes or python scripts? I was hoping to see what other capabilities might have been created for the Geostatistical Analyst extension. Regards, Simon

‎08-27-2019

Hi, Sorry, I was wondering whether somebody might be able to help provide a brief summary of how to calculate potential improvements in the kriging prediction error by adding or removing sample sites. I would like to use Geostatistical Analyst to optimize my monitoring network. The first step I would like to do is calculate the average standard kriging error for a range of different sized networks so I can create something called a Network Density Graph (attached). From this graph I plan on selecting the optimum number of wells and then using the Densify Sample Network tool to locate my site. Kind regards, Simon

‎08-26-2019

Hi What is the difference between the standard Error calculated using GA Layer to Points and the standard error in Cross Validation? I noticed that during my cross validation (step 5 of the kriging wizard) the errors differ compared with the results I get when using the same model and same location but extracting using the GA Layer to points. Regards, Simon

‎08-26-2019

I'm trying to use Geostatistical Analyst to create a Network Density Graph. This involves evaluating changes in the standard deviation of the estimation error by looking at different sized networks. From what I understand the standard deviation of the estimation error is independent of the actual measurements so that once the kriging model is determined it can be used to test the effect of new locations on the standard deviation of the estimation error without needing measurements of z. My question is: How do I use Geostatistical Analyst to do this? This are the steps I think I should follow: 1. Create a Geostatistical model for testing - In this step I optimize my kriging model 2. Create different sized networks for testing - Here use a range of hexagonal sample arrays to generate samples of increasing size. 3. Create new Geostatistical layers for the different sized networks using the model parameters derived in step one - In this step I create several new Geostatistical layers for each of the different sample configurations. 4. Evaluate the global performance (using the average standard deviation of the estimation error) from each new Geostastical layer created in step 3 by abstracting GA layer to points - here I have sample points across my study area that I use to extract the standard errors from each of the Geostatistical layers. 5. Plot the results on a line graph - this should show that as the network density increases so to will the standard deviation of the estimation error I'm not sure where I'm going wrong but my prediction errors increase as my network becomes denser. Any help is appreciated. Cheers, Simon

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Latest Contributions by SimonHarper

Re: Adding or removing new sites to assess changes in the kriging standard error

Re: Adding or removing new sites to assess changes in the kriging standard error

Re: Optimising monitoring networks using Kriging

Re: Optimising monitoring networks using Kriging

Re: Optimising monitoring networks using Kriging

Where to search for custom toolboxes

Adding or removing new sites to assess changes in the kriging standard error

Why do my standard errors differ?

Optimising monitoring networks using Kriging