Re: [ai-geostats] spatial relationships

2004-09-03 Thread Chaosheng Zhang
r 02, 2004 3:30 PM Subject: [ai-geostats] spatial relationships Dear oh Dear, I am failing to communicate (again). As far as I know, I didn't say you could not use geostatistics when a trend is present! I regularly use Universal Kriging for data with a trend and kriging with an external

[ai-geostats] spatial relationships

2004-09-02 Thread Isobel Clark
Dear oh Dear, I am failing to communicate (again). As far as I know, I didn't say you could not use geostatistics when a trend is present! I regularly use Universal Kriging for data with a trend and kriging with an external drift when the trend is governed by an outside factor (see free tutorial

[ai-geostats] spatial relationships

2004-09-01 Thread Isobel Clark
Mark I could not agree more with Gregoire (with one proviso, see below). Both geostatistics and any weighted average estimators are based on the same assumptions -- that relationship between values at two locations depends on the distance between them and (possibly) their relative orientation.