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ArcGIS Geostatistical Analyst -- how does it display / fit variograms?
9 messages · D G Rossiter, ONKELINX, Thierry, Barry Rowlingson +6 more
Hi, A lot of people in our institute use ArcGIS. But I always advise them not to use ArcGIS for kriging etc. Mainly because kriging in ArcGIS is a black box tool. You only know the input and the output, but not how things are calculated. More over people tend to try the different options without really knowing what (and why) they are doing. The just stick with the interpolated map that "looks" the best. For kriging I promote R and gstat. HTH, Thierry ------------------------------------------------------------------------ ---- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 Thierry.Onkelinx at inbo.be www.inbo.be To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey -----Oorspronkelijk bericht----- Van: r-sig-geo-bounces at stat.math.ethz.ch [mailto:r-sig-geo-bounces at stat.math.ethz.ch] Namens D G Rossiter Verzonden: zaterdag 6 september 2008 16:07 Aan: r-sig-geo at stat.math.ethz.ch Onderwerp: [R-sig-Geo] ArcGIS Geostatistical Analyst -- how does it display /fit variograms? Hi, I know this is mostly an R-spatial list but this is where the most computational geostats experts hang out, so please forgive me for asking an ArcGIS question. I use R almost exclusively for my own work, but have been asked to supervise the development of an introductory geostats course for our partner at the University of Rwanda. They have standardized on ArcGIS for all of their GIS work (and SPSS for non-spatial stats), and the prospective students (mostly centre workers and collaborating researchers) are familiar with it. The decision was taken by their administration not to use my R/gstat material from the ITC distance education course, rather to develop the course with ArcGIS. My counterpart is now with me developing the course. The deficiencies of ESRI documentation are well-known. I have dug around quite a bit both within the ESRI docs (on-line and with the program) and through various mailing lists and the web and can not find out some basic information. I hope you can shed some light, 1. What exactly is the display of the empirical variogram? The doc. implies there is one average semivariance per bin (as is usual) but the display often has several at the same bin. The variogram can be exported as a table, where it shows multiple (2 - 6 or so) semivariances for each bin; the table also shows a "weight" for each of these, but they do not add to 1 or 100 or anything I can recognize! The close-range bins usually have one, then the number increases. So I guess each dot represents some number of point-pairs. 2. How is the variogram being fit? What weighting, what solver? If the user changes the cutoff/bin width, the solution changes (as it should); but I can't see how it's solving, and I can't find any option to change the weighting (as in e.g. gstat). 3. When fitting direct and cross-variograms for co-kriging, it seems that a linear model of co-regionalization is being enforced (i.e. same range). Again, how is the fit being done? Like fit.lmc in gstat? Naturally we want the students to understand what the program is doing for them! Although ESRI promotes "press the button and look at the cross-validation". I do like their disclaimer in the ArcGIS Desktop 9.3 help: "Kriging is a complex procedure that requires greater knowledge about spatial statistics than can be conveyed in this command reference". They then ref. Burrough (1986! not even the revised book), Heine (1986), McBratney & Webster Journal of Soil Sci. 37:317 (1986), Oliver IJGIS 4 (1990), Press etc. Numerical Recipes, and Royle et al. Geoprocessing 1 (1981). Not exactly the most up to date or accessible reference list (no offrence to the fine authors mentioned). Thanks for your help. D. G. Rossiter Senior University Lecturer Department of Earth Systems Analysis International Institute for Geo-Information Science and Earth Observation (ITC) PO Box 6, 7500 AA Enschede, The Netherlands Internet: http://www.itc.nl/personal/rossiter/pubs/list.html#pubs_m_R International Institute for Geo-Information Science and Earth Observation (ITC) Chamber of Commerce: 410 27 560 E-mail disclaimer The information in this e-mail, including any attachments, is intended for the addressee only. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution or action in relation to the content of this information is strictly prohibited. If you have received this e-mail by mistake, please delete the message and any attachment and inform the sender by return e-mail. ITC accepts no liability for any error or omission in the message content or for damage of any kind that may arise as a result of e-mail transmission. _______________________________________________ R-sig-Geo mailing list R-sig-Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver weer en binden het INBO onder geen enkel beding, zolang dit bericht niet bevestigd is door een geldig ondertekend document.%CRLF%The views expressed in this message and any annex are purely those of the writer and may not be regarded as stating an official position of INBO, as long as the message is not confirmed by a duly signed document%CRLF%
2008/9/6 D G Rossiter <rossiter at itc.nl>:
Naturally we want the students to understand what the program is doing for them! Although ESRI promotes "press the button and look at the cross-validation". I do like their disclaimer in the ArcGIS Desktop 9.3 help: "Kriging is a complex procedure that requires greater knowledge about spatial statistics than can be conveyed in this command reference". They then ref. Burrough (1986! not even the revised book), Heine (1986), McBratney & Webster Journal of Soil Sci. 37:317 (1986), Oliver IJGIS 4 (1990), Press etc. Numerical Recipes, and Royle et al. Geoprocessing 1 (1981). Not exactly the most up to date or accessible reference list (no offrence to the fine authors mentioned).
For software that costs $2500 dollars for a single-user license, I'd expect documentation written in gold-leaf on human skin parchment. I wouldn't expect to be palmed off with 'this bit is tricky, go read some books', I'd expect the software to do just about everything, explain what it was doing in the language of your choice, and give you a backrub at the same time. I'm flabbergasted that a solution for what is probably not one of the richest universities in the world is going to tie them to one of the most expensive geostats packages I've ever seen. I'm staring at this pricetag on the ESRI web site because I just feel like I must be hallucinating. But I'm not. Two and a half THOUSAND dollars. Oh, and you need an ArcView license as well, a mere snip at one and half thousand dollars. Zimbabwe dollars? No, US dollars. I checked. I'm guessing you can't rethink your plans at this point, but you could consider pointing out to students that free, cross-platform, high-quality, open-source, well-documented software for statistics and geostatistics is available to download from www.r-project.org, and there's a friendly bunch of people willing to answer sensible questions on the mailing list (including those professors who make it their business to echo 'please read the posting guide' all the time). Hope this doesn't come over as too much of a rant, but I'm running a course on Open-Source GeoSpatial Software in November and I think I may have just found a nice counter-example :) Barry [think I need a cup of tea and a lie-down now]
On Sat, 6 Sep 2008, Barry Rowlingson wrote:
2008/9/6 D G Rossiter <rossiter at itc.nl>:
Naturally we want the students to understand what the program is doing for them! Although ESRI promotes "press the button and look at the cross-validation". I do like their disclaimer in the ArcGIS Desktop 9.3 help: "Kriging is a complex procedure that requires greater knowledge about spatial statistics than can be conveyed in this command reference". They then ref. Burrough (1986! not even the revised book), Heine (1986), McBratney & Webster Journal of Soil Sci. 37:317 (1986), Oliver IJGIS 4 (1990), Press etc. Numerical Recipes, and Royle et al. Geoprocessing 1 (1981). Not exactly the most up to date or accessible reference list (no offrence to the fine authors mentioned).
For software that costs $2500 dollars for a single-user license, I'd expect documentation written in gold-leaf on human skin parchment. I wouldn't expect to be palmed off with 'this bit is tricky, go read some books', I'd expect the software to do just about everything, explain what it was doing in the language of your choice, and give you a backrub at the same time. I'm flabbergasted that a solution for what is probably not one of the richest universities in the world is going to tie them to one of the most expensive geostats packages I've ever seen. I'm staring at this pricetag on the ESRI web site because I just feel like I must be hallucinating. But I'm not. Two and a half THOUSAND dollars. Oh, and you need an ArcView license as well, a mere snip at one and half thousand dollars. Zimbabwe dollars? No, US dollars. I checked. I'm guessing you can't rethink your plans at this point, but you could consider pointing out to students that free, cross-platform, high-quality, open-source, well-documented software for statistics and geostatistics is available to download from www.r-project.org, and there's a friendly bunch of people willing to answer sensible questions on the mailing list (including those professors who make it their business to echo 'please read the posting guide' all the time). Hope this doesn't come over as too much of a rant, but I'm running a course on Open-Source GeoSpatial Software in November and I think I may have just found a nice counter-example :) Barry [think I need a cup of tea and a lie-down now]
And FOSS4G 2008 is about to happen in Cape Town! http://conference.osgeo.org/index.php/foss4g/2008 Just think what these young scientists could do with QGIS/GRASS/R/gstat or other suitable toolchains! However, I've seen similar things, I'm afraid they may be being driven by clueless "donor" organisations. I've just put the tea on ... Roger
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: Roger.Bivand at nhh.no
I faced the problem of collecting informations about ArcGIS Geospatial extension while I was following the geostatics course at university. A month looking for documentation about what was behind the scene, but nothing... Just basics explanations about kriging. That's when I've discovered gstat! In the Institute I come from ArcGIS/ArcInfo is the most widely used system, for cartography and geoDB management. But nobody would use it for geostatistical analysis! Ok, IDW, or other simple interpolations, but nothing beyond this. The only reason I would spend money for commercial software can be Geovariances software (in the Institute they use Isatis) [1], nothing else. Giovanni [1] http://www.geovariances.com/ 2008/9/6 Roger Bivand <Roger.Bivand at nhh.no>:
On Sat, 6 Sep 2008, Barry Rowlingson wrote:
2008/9/6 D G Rossiter <rossiter at itc.nl>:
Naturally we want the students to understand what the program is doing for them! Although ESRI promotes "press the button and look at the cross-validation". I do like their disclaimer in the ArcGIS Desktop 9.3 help: "Kriging is a complex procedure that requires greater knowledge about spatial statistics than can be conveyed in this command reference". They then ref. Burrough (1986! not even the revised book), Heine (1986), McBratney & Webster Journal of Soil Sci. 37:317 (1986), Oliver IJGIS 4 (1990), Press etc. Numerical Recipes, and Royle et al. Geoprocessing 1 (1981). Not exactly the most up to date or accessible reference list (no offrence to the fine authors mentioned).
For software that costs $2500 dollars for a single-user license, I'd expect documentation written in gold-leaf on human skin parchment. I wouldn't expect to be palmed off with 'this bit is tricky, go read some books', I'd expect the software to do just about everything, explain what it was doing in the language of your choice, and give you a backrub at the same time. I'm flabbergasted that a solution for what is probably not one of the richest universities in the world is going to tie them to one of the most expensive geostats packages I've ever seen. I'm staring at this pricetag on the ESRI web site because I just feel like I must be hallucinating. But I'm not. Two and a half THOUSAND dollars. Oh, and you need an ArcView license as well, a mere snip at one and half thousand dollars. Zimbabwe dollars? No, US dollars. I checked. I'm guessing you can't rethink your plans at this point, but you could consider pointing out to students that free, cross-platform, high-quality, open-source, well-documented software for statistics and geostatistics is available to download from www.r-project.org, and there's a friendly bunch of people willing to answer sensible questions on the mailing list (including those professors who make it their business to echo 'please read the posting guide' all the time). Hope this doesn't come over as too much of a rant, but I'm running a course on Open-Source GeoSpatial Software in November and I think I may have just found a nice counter-example :) Barry [think I need a cup of tea and a lie-down now]
And FOSS4G 2008 is about to happen in Cape Town! http://conference.osgeo.org/index.php/foss4g/2008 Just think what these young scientists could do with QGIS/GRASS/R/gstat or other suitable toolchains! However, I've seen similar things, I'm afraid they may be being driven by clueless "donor" organisations. I've just put the tea on ... Roger
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
-- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: Roger.Bivand at nhh.no
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
This is a bit of a distant memory from a few years back when I also was trying to better understand what ArcGIS was actually doing, but I believe there is some, though probably not a large amount of, additional technical detail available in the following ESRI manuals: Johnston, K. et al. 2001. Using ArcGIS geostatistical analyst. Redlands, CA: Environmental Systems Research Institute. McCoy, J. et al. 2001. Using ArcGIS spatial analyst. Redlands, CA: Environmental Systems Research Institute. I don't think I was able to find these online as I have a memory of tracking them down through the university map library. -chris ---------------------------------------------------------------------------------------------- Chris Paciorek / Asst. Professor Email: paciorek at hsph.harvard.edu Department of Biostatistics Voice: 617-432-4912 Harvard School of Public Health Fax: 617-432-5619 655 Huntington Av., Bldg. 2-407 WWW: www.biostat.harvard.edu/~paciorek Boston, MA 02115 USA Permanent forward: paciorek at alumni.cmu.edu
"G. Allegri" <giohappy at gmail.com> 09/06/08 1:45 PM >>>
I faced the problem of collecting informations about ArcGIS Geospatial extension while I was following the geostatics course at university. A month looking for documentation about what was behind the scene, but nothing... Just basics explanations about kriging. That's when I've discovered gstat! In the Institute I come from ArcGIS/ArcInfo is the most widely used system, for cartography and geoDB management. But nobody would use it for geostatistical analysis! Ok, IDW, or other simple interpolations, but nothing beyond this. The only reason I would spend money for commercial software can be Geovariances software (in the Institute they use Isatis) [1], nothing else. Giovanni [1] http://www.geovariances.com/ 2008/9/6 Roger Bivand <Roger.Bivand at nhh.no>:
On Sat, 6 Sep 2008, Barry Rowlingson wrote:
2008/9/6 D G Rossiter <rossiter at itc.nl>:
Naturally we want the students to understand what the program is doing for them! Although ESRI promotes "press the button and look at the cross- validation". I do like their disclaimer in the ArcGIS Desktop 9.3 help: "Kriging is a complex procedure that requires greater knowledge about spatial statistics than can be conveyed in this command reference". They then ref. Burrough (1986! not even the revised book), Heine (1986), McBratney & Webster Journal of Soil Sci. 37:317 (1986), Oliver IJGIS 4 (1990), Press etc. Numerical Recipes, and Royle et al. Geoprocessing 1 (1981). Not exactly the most up to date or accessible reference list (no offrence to the fine authors mentioned).
For software that costs $2500 dollars for a single- user license, I'd expect documentation written in gold- leaf on human skin parchment. I wouldn't expect to be palmed off with 'this bit is tricky, go read some books', I'd expect the software to do just about everything, explain what it was doing in the language of your choice, and give you a backrub at the same time. I'm flabbergasted that a solution for what is probably not one of the richest universities in the world is going to tie them to one of the most expensive geostats packages I've ever seen. I'm staring at this pricetag on the ESRI web site because I just feel like I must be hallucinating. But I'm not. Two and a half THOUSAND dollars. Oh, and you need an ArcView license as well, a mere snip at one and half thousand dollars. Zimbabwe dollars? No, US dollars. I checked. I'm guessing you can't rethink your plans at this point, but you could consider pointing out to students that free, cross- platform, high- quality, open- source, well- documented software for statistics and geostatistics is available to download from www.r- project.org, and there's a friendly bunch of people willing to answer sensible questions on the mailing list (including those professors who make it their business to echo 'please read the posting guide' all the time). Hope this doesn't come over as too much of a rant, but I'm running a course on Open- Source GeoSpatial Software in November and I think I may have just found a nice counter- example :) Barry [think I need a cup of tea and a lie- down now]
And FOSS4G 2008 is about to happen in Cape Town! http://conference.osgeo.org/index.php/foss4g/2008 Just think what these young scientists could do with QGIS/GRASS/R/gstat or other suitable toolchains! However, I've seen similar things, I'm afraid they may be being driven by clueless "donor" organisations. I've just put the tea on ... Roger
_______________________________________________ R- sig- Geo mailing list R- sig- Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r- sig- geo
-- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N- 5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e- mail: Roger.Bivand at nhh.no
_______________________________________________ R- sig- Geo mailing list R- sig- Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r- sig- geo
_______________________________________________ R- sig- Geo mailing list R- sig- Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r- sig- geo
Nothing else to say after Barry's email, apart from noting yet another wonder of the free software world/community: we even use our mailing lists to provide advice on commercial software!!! Uau! Would the reverse be true? Paulo Justiniano Ribeiro Jr LEG (Laboratorio de Estatistica e Geoinformacao) Universidade Federal do Parana Caixa Postal 19.081 CEP 81.531-990 Curitiba, PR - Brasil Tel: (+55) 41 3361 3573 Fax: (+55) 41 3361 3141 e-mail: paulojus AT ufpr br http://www.leg.ufpr.br/~paulojus
On Sat, 6 Sep 2008, Christopher Paciorek wrote:
This is a bit of a distant memory from a few years back when I also was trying to better understand what ArcGIS was actually doing, but I believe there is some, though probably not a large amount of, additional technical detail available in the following ESRI manuals: Johnston, K. et al. 2001. Using ArcGIS geostatistical analyst. Redlands, CA: Environmental Systems Research Institute. McCoy, J. et al. 2001. Using ArcGIS spatial analyst. Redlands, CA: Environmental Systems Research Institute. I don't think I was able to find these online as I have a memory of tracking them down through the university map library. -chris ---------------------------------------------------------------------------------------------- Chris Paciorek / Asst. Professor Email: paciorek at hsph.harvard.edu Department of Biostatistics Voice: 617-432-4912 Harvard School of Public Health Fax: 617-432-5619 655 Huntington Av., Bldg. 2-407 WWW: www.biostat.harvard.edu/~paciorek Boston, MA 02115 USA Permanent forward: paciorek at alumni.cmu.edu
"G. Allegri" <giohappy at gmail.com> 09/06/08 1:45 PM >>>
I faced the problem of collecting informations about ArcGIS Geospatial extension while I was following the geostatics course at university. A month looking for documentation about what was behind the scene, but nothing... Just basics explanations about kriging. That's when I've discovered gstat! In the Institute I come from ArcGIS/ArcInfo is the most widely used system, for cartography and geoDB management. But nobody would use it for geostatistical analysis! Ok, IDW, or other simple interpolations, but nothing beyond this. The only reason I would spend money for commercial software can be Geovariances software (in the Institute they use Isatis) [1], nothing else. Giovanni [1] http://www.geovariances.com/ 2008/9/6 Roger Bivand <Roger.Bivand at nhh.no>:
On Sat, 6 Sep 2008, Barry Rowlingson wrote:
2008/9/6 D G Rossiter <rossiter at itc.nl>:
Naturally we want the students to understand what the program is doing for them! Although ESRI promotes "press the button and look at the cross- validation". I do like their disclaimer in the ArcGIS Desktop 9.3 help: "Kriging is a complex procedure that requires greater knowledge about spatial statistics than can be conveyed in this command reference". They then ref. Burrough (1986! not even the revised book), Heine (1986), McBratney & Webster Journal of Soil Sci. 37:317 (1986), Oliver IJGIS 4 (1990), Press etc. Numerical Recipes, and Royle et al. Geoprocessing 1 (1981). Not exactly the most up to date or accessible reference list (no offrence to the fine authors mentioned).
For software that costs $2500 dollars for a single- user license, I'd expect documentation written in gold- leaf on human skin parchment. I wouldn't expect to be palmed off with 'this bit is tricky, go read some books', I'd expect the software to do just about everything, explain what it was doing in the language of your choice, and give you a backrub at the same time. I'm flabbergasted that a solution for what is probably not one of the richest universities in the world is going to tie them to one of the most expensive geostats packages I've ever seen. I'm staring at this pricetag on the ESRI web site because I just feel like I must be hallucinating. But I'm not. Two and a half THOUSAND dollars. Oh, and you need an ArcView license as well, a mere snip at one and half thousand dollars. Zimbabwe dollars? No, US dollars. I checked. I'm guessing you can't rethink your plans at this point, but you could consider pointing out to students that free, cross- platform, high- quality, open- source, well- documented software for statistics and geostatistics is available to download from www.r- project.org, and there's a friendly bunch of people willing to answer sensible questions on the mailing list (including those professors who make it their business to echo 'please read the posting guide' all the time). Hope this doesn't come over as too much of a rant, but I'm running a course on Open- Source GeoSpatial Software in November and I think I may have just found a nice counter- example :) Barry [think I need a cup of tea and a lie- down now]
And FOSS4G 2008 is about to happen in Cape Town! http://conference.osgeo.org/index.php/foss4g/2008 Just think what these young scientists could do with QGIS/GRASS/R/gstat or other suitable toolchains! However, I've seen similar things, I'm afraid they may be being driven by clueless "donor" organisations. I've just put the tea on ... Roger
_______________________________________________ R- sig- Geo mailing list R- sig- Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r- sig- geo
-- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N- 5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e- mail: Roger.Bivand at nhh.no
_______________________________________________ R- sig- Geo mailing list R- sig- Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r- sig- geo
_______________________________________________ R- sig- Geo mailing list R- sig- Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r- sig- geo _______________________________________________ R-sig-Geo mailing list R-sig-Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Paulo Justiniano Ribeiro Jr wrote:
Nothing else to say after Barry's email, apart from noting yet another wonder of the free software world/community: we even use our mailing lists to provide advice on commercial software!!! Uau! Would the reverse be true?
Paulo, this might be less utopic than it sounds. I've heard that at ESRI Redlands there are quite a few active, and I presume happy, R users. -- Edzer
1 day later
Hi, You can download the geostat-manual from http://dusk2.geo.orst.edu/gis/geostat_analyst.pdf and http://www.ci.uri.edu/projects/geostats/Using_ArcGIS_Geostat_Anal_Tutor.pdf and the spatial-analyst manual from http://www.maproom.ruc.dk/software/arcmap/using_spatial_analyst.pdf/view and http://www.gis.unbc.ca/help/software/esri/Tutorials/Using_ArcGIS_Spatial_Analyst_Tutorial.pdf Henk Henk Sierdsema SOVON Vogelonderzoek Nederland / SOVON Dutch Centre for Field Ornithology Rijksstraatweg 178 6573 DG Beek-Ubbergen The Netherlands tel: +31 (0)24 6848145 fax: +31 (0)24 6848122 -----Oorspronkelijk bericht----- Van: Christopher Paciorek [mailto:paciorek at hsph.harvard.edu] Verzonden: zaterdag 6 september 2008 20:44 Aan: G. Allegri CC: r-sig-geo at stat.math.ethz.ch Onderwerp: Re: [R-sig-Geo] ArcGIS Geostatistical Analyst -- how does itdisplay/ fit variograms? This is a bit of a distant memory from a few years back when I also was trying to better understand what ArcGIS was actually doing, but I believe there is some, though probably not a large amount of, additional technical detail available in the following ESRI manuals: Johnston, K. et al. 2001. Using ArcGIS geostatistical analyst. Redlands, CA: Environmental Systems Research Institute. McCoy, J. et al. 2001. Using ArcGIS spatial analyst. Redlands, CA: Environmental Systems Research Institute. I don't think I was able to find these online as I have a memory of tracking them down through the university map library. -chris ---------------------------------------------------------------------------------------------- Chris Paciorek / Asst. Professor Email: paciorek at hsph.harvard.edu Department of Biostatistics Voice: 617-432-4912 Harvard School of Public Health Fax: 617-432-5619 655 Huntington Av., Bldg. 2-407 WWW: www.biostat.harvard.edu/~paciorek Boston, MA 02115 USA Permanent forward: paciorek at alumni.cmu.edu
"G. Allegri" <giohappy at gmail.com> 09/06/08 1:45 PM >>>
I faced the problem of collecting informations about ArcGIS Geospatial extension while I was following the geostatics course at university. A month looking for documentation about what was behind the scene, but nothing... Just basics explanations about kriging. That's when I've discovered gstat! In the Institute I come from ArcGIS/ArcInfo is the most widely used system, for cartography and geoDB management. But nobody would use it for geostatistical analysis! Ok, IDW, or other simple interpolations, but nothing beyond this. The only reason I would spend money for commercial software can be Geovariances software (in the Institute they use Isatis) [1], nothing else. Giovanni [1] http://www.geovariances.com/ 2008/9/6 Roger Bivand <Roger.Bivand at nhh.no>:
On Sat, 6 Sep 2008, Barry Rowlingson wrote:
2008/9/6 D G Rossiter <rossiter at itc.nl>:
Naturally we want the students to understand what the program is doing for them! Although ESRI promotes "press the button and look at the cross- validation". I do like their disclaimer in the ArcGIS Desktop 9.3 help: "Kriging is a complex procedure that requires greater knowledge about spatial statistics than can be conveyed in this command reference". They then ref. Burrough (1986! not even the revised book), Heine (1986), McBratney & Webster Journal of Soil Sci. 37:317 (1986), Oliver IJGIS 4 (1990), Press etc. Numerical Recipes, and Royle et al. Geoprocessing 1 (1981). Not exactly the most up to date or accessible reference list (no offrence to the fine authors mentioned).
For software that costs $2500 dollars for a single- user license, I'd expect documentation written in gold- leaf on human skin parchment. I wouldn't expect to be palmed off with 'this bit is tricky, go read some books', I'd expect the software to do just about everything, explain what it was doing in the language of your choice, and give you a backrub at the same time. I'm flabbergasted that a solution for what is probably not one of the richest universities in the world is going to tie them to one of the most expensive geostats packages I've ever seen. I'm staring at this pricetag on the ESRI web site because I just feel like I must be hallucinating. But I'm not. Two and a half THOUSAND dollars. Oh, and you need an ArcView license as well, a mere snip at one and half thousand dollars. Zimbabwe dollars? No, US dollars. I checked. I'm guessing you can't rethink your plans at this point, but you could consider pointing out to students that free, cross- platform, high- quality, open- source, well- documented software for statistics and geostatistics is available to download from www.r- project.org, and there's a friendly bunch of people willing to answer sensible questions on the mailing list (including those professors who make it their business to echo 'please read the posting guide' all the time). Hope this doesn't come over as too much of a rant, but I'm running a course on Open- Source GeoSpatial Software in November and I think I may have just found a nice counter- example :) Barry [think I need a cup of tea and a lie- down now]
And FOSS4G 2008 is about to happen in Cape Town! http://conference.osgeo.org/index.php/foss4g/2008 Just think what these young scientists could do with QGIS/GRASS/R/gstat or other suitable toolchains! However, I've seen similar things, I'm afraid they may be being driven by clueless "donor" organisations. I've just put the tea on ... Roger
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-- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N- 5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e- mail: Roger.Bivand at nhh.no
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