Re: AI-GEOSTATS: Kt estimation variance

2003-10-24 Thread sebastiano trevisani
Dear Isobel Clark Thank you very for your help I have used the software on your web site and I have understood more precisely in which way kriging estimation variance works Sincerely Sebastiano Trevisani -- * To post a message to the list, send it to [EMAIL PROTECTED] * As a general se

Re: AI-GEOSTATS: geoR and memory

2003-10-24 Thread Julian Burgos
Hello everyone, Here is a link to Geotrans, a program developed by the US National Imagery and Mapping Agency to convert locations between different coordinate systems. http://earth-info.nima.mil/GandG/geotrans/geotrans.html It can work in batch mode. Julian M. Burgos University of Washington Sc

Re: AI-GEOSTATS: geoR and memory

2003-10-24 Thread Jim Bash
On Fri, 24 Oct 2003, Susan King wrote: > I would like to have algorithms for converting lat/long into different > projections (albers, utm). You might check out http://www.remotesensing.org/proj/ which has source and documentation for PROJ.4, map projection software. I think the source is in C an

Re: AI-GEOSTATS: geoR and memory

2003-10-24 Thread Jim Bash
On Fri, 24 Oct 2003, [iso-8859-1] Isobel Clark wrote: > > - convert your longitude > > and latitude data into a planar projection first > Do you have an algorithm that works everywhere in the > world? There is no single projection that would be appropriate for everywhere in the world at once, just

AI-GEOSTATS: tick sampling

2003-10-24 Thread Russell Barbour
Dear All, I am trying to fiugre out how many locations I need for a sample of ticks in the eastern United States. I know that teh rule of thumb is that that no less than twenty pairs are required per distance class, but is there any other refrence on sampling for spatial analysis? Thank you Ru

Re: AI-GEOSTATS: geoR and memory

2003-10-24 Thread Susan King
I would like to have algorithms for converting lat/long into different projections (albers, utm). Susan L. King Operations Research Analyst USDA Forest Service 11 Campus Blvd., Suite 200 Newtown Square, PA 19073 Phone: (610) 557-4048 Email: [EMAIL PROTECTED] FAX: (610) 557-4250

Re: AI-GEOSTATS: geoR and memory

2003-10-24 Thread Martin Roseveare
Isobel, There are published algorithms that will do this - one of the advantages of the UTM projection is that it can be generated anywhere, with the zoning of the projection accounting for the necessary differences around the globe. Good software should be able to deal with UTM zones and hence wo

Re: AI-GEOSTATS: Kt estimation variance

2003-10-24 Thread Isobel Clark
Sebastiano Large kriging variances have nothing to do with negative weights. The two are completely different phenomena - especially in Universal Kriging. In Ordinary Kriging the estimation variance can become as high as two times the total sill of the semi-variogram. This is a theoretical fact

AI-GEOSTATS: Kt estimation variance

2003-10-24 Thread sebastiano trevisani
Hello ai-geostats list-members Performing an universal kriging on chemical data (log transform of concentration), in some estimation points I obtained an estimation variance larger (in some case three times) than the sill of residual variogram. From what I know this is related to negative weigh

Re: AI-GEOSTATS: geoR and memory

2003-10-24 Thread Isobel Clark
Martin > - convert your longitude > and latitude data into a planar projection first Do you have an algorithm that works everywhere in the world? Isobel http://geoecosse.bizland.com/whatsnew.htm Want to chat instantly wit

Re: AI-GEOSTATS: geoR and memory

2003-10-24 Thread Martin Roseveare
Just to reinforce what Edzer said about projections - convert your longitude and latitude data into a planar projection first - UTM should be OK though check your data doesn't cross zones. If you don't do this the stats will not produce meaningful results as degrees are not a correct spatial measur