AI-GEOSTATS: Choosing Lag Distance and Angular Tolerance

2001-05-15 Thread Yadollah Waghei
Hello dears I have a spatial data set contaning n=262 observarion (The variable of interest is Rate of Tuberculosis in 262 counties of Iran). I want to fit some models to Directional semi-variograms,and then build anisotropic semi-variogram. Then questions are - Is there any rule for choosing

Re: AI-GEOSTATS: The Estimation of Range paramter is very very big

2001-05-15 Thread Isobel Clark
Are you using some kind of automated fitting? The results would suggest that the model is inappropriate or that your basic assumptions are inappropriate. You should look at how the models are being fitted and what assumptions are made and question everything. Isobel Clark

Re: AI-GEOSTATS: Choosing Lag Distance and Angular Tolerance

2001-05-15 Thread Isobel Clark
Andrew You can apply 'standard' geostatistics if the measurements are the 'average' (or some similar feature) over an area. It makes interpeting the semi-variogram extremely tricky if you combine many different sizes of sample, but common sense is the main thing here. The trick is to derive a

AI-GEOSTATS: Number of data points Variograms

2001-05-15 Thread K. Ramanitharan
Dear AI-GEOSTATiSticians, My research is on heavy metal pollution in water bodies. As a part of the analysis, I am doing kriging with the pollutant data. I have couple of problems in doing this task. 1. Though I have the data sets for 90 water bodies, most of them (85) have data points less

Re: AI-GEOSTATS: Number of data points Variograms

2001-05-15 Thread Isobel Clark
My research is on heavy metal pollution in water bodies. Hi, some thoughts (your numbering): (1) One of the things I have found successful is the following: construct your semi-variogram using ALL of your data but not allowing pairs between samples in different water bodies;