Re: AI-GEOSTATS: Kriging a non-planar surface lacking natural parametization
Peter Bossew wrote: I think Olumide's question was, what to do if the underlying manifold is not euclidean nor spheric or something regular of that kind. Thanks for clearing up my question Peter. The object I'm interested is a bone, and its by no means regular or easily parameterizable. Can anyone suggest references I could look into? Thanks - Olumide + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/
Re: AI-GEOSTATS: Kriging a non-planar surface lacking natural parametization
"Edzer J. Pebesma" <[EMAIL PROTECTED]> writes: > >There has been some work on geostatistics on the sphere -- the >challenges faced here included, afaics (i) to find and use distance >functions, such as great circle distance, and a suitable earth model >(sphere or rather ellispsoid) and (ii) to find and use covariance >function that are positive defnite for the sphere or particular >ellipsoid used. The R packages fields (and recently, to some extent >gstat) do address some of these issues, but are constrained to be used >on Earth. >I was watching Armageddon last night, and indeed the thing didn't come >close to a sphere or ellipsoid... great to hear someone is actually >worrying about kriging on meteorites. Beyond planetary geostatistics -- >this might be interstellar geostatistics? hm ! If someone attempts to krige across the event horizon of a black hole, please let the list know ! ;-) p (sorry, not too helpful for Olumide) > >Could you show us a bit more how you do parameterize your particular >non-planar surface? >-- >Edzer > >sebastiano trevisani wrote: >> Hi >> >> I'm not sure to understand what you mean when you say kriging on non >> planar surface. >> If you are saying that you need to interpolate on to an irregular >> grid, both GSLIB and GSTAT (and so R) permit >> you to interpolate whatever set of points. >> >> >> Bye >> Sebastiano T. >> >> At 03.14 03/04/2007, Olumide wrote: >>> Hello - >>> >>> (I'm relatively new to the subject and to the forum.) >>> >>> Are there any methods for kriging non-planar surfaces that have no >>> natural parametrization e.g. a meteorite. >>> >>> Thanks, >>> >>> - Olumide >>> + > + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/
Re: AI-GEOSTATS: Kriging a non-planar surface lacking natural parametization
Hi Peter Well!!! if the point is this the things become quite difficult If the problem is to take in to account the roughness of topography in order to compute distances I think that with GIS technologies is possible to find an answer. Surely things become more complex if you have obstacles (like islands when interpolating oceanographic parameters). From what I remember the issue of complex geometries is covered in the field of geostatistical geomodeling. In fact in this field you have to work with really 3d complex morphologies. Ciao Sebastiano T. At 12.31 03/04/2007, Peter Bossew wrote: Hi Sebastiano, I think Olumide's question was, what to do if the underlying manifold is not euclidean nor spheric or something regular of that kind. How would you define the distance beween pairs of points on the surface of a potatoe, or how would you lay a regular grid on a potatoe, which covers more than a local vicinity (which can be approximated planar or spherical) ? This is indeed by no means a trivial question, I think, well worth some thoughts of the geostats gurus I remember Gregoire Dubois has once suggested non-euclidean variography (defining distances which account for topography between the points). He is currently on hoildays, but he may have ideas about that. ciao, Peter sebastiano trevisani <[EMAIL PROTECTED]> writes: >Hi > >I'm not sure to understand what you mean when you say kriging on non >planar surface. >If you are saying that you need to interpolate on to an irregular >grid, both GSLIB and GSTAT (and so R) permit >you to interpolate whatever set of points. > > >Bye >Sebastiano T. > >At 03.14 03/04/2007, Olumide wrote: >>Hello - >> >>(I'm relatively new to the subject and to the forum.) >> >>Are there any methods for kriging non-planar surfaces that have no >>natural parametrization e.g. a meteorite. >> >>Thanks, >> >>- Olumide >>+ - Peter Bossew European Commission (EC) Joint Research Centre (JRC) Institute for Environment and Sustainability (IES) TP 441, Via Fermi 1 21020 Ispra (VA) ITALY Tel. +39 0332 78 9109 Fax. +39 0332 78 5466 Email: [EMAIL PROTECTED] WWW: http://rem.jrc.cec.eu.int "The views expressed are purely those of the writer and may not in any circumstances be regarded as stating an official position of the European Commission." + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/
Re: AI-GEOSTATS: Kriging a non-planar surface lacking natural parametization e.g. meteorite
Olumide, There has been some work on geostatistics on the sphere -- the challenges faced here included, afaics (i) to find and use distance functions, such as great circle distance, and a suitable earth model (sphere or rather ellispsoid) and (ii) to find and use covariance function that are positive defnite for the sphere or particular ellipsoid used. The R packages fields (and recently, to some extent gstat) do address some of these issues, but are constrained to be used on Earth. I was watching Armageddon last night, and indeed the thing didn't come close to a sphere or ellipsoid... great to hear someone is actually worrying about kriging on meteorites. Beyond planetary geostatistics -- this might be interstellar geostatistics? Could you show us a bit more how you do parameterize your particular non-planar surface? -- Edzer sebastiano trevisani wrote: Hi I'm not sure to understand what you mean when you say kriging on non planar surface. If you are saying that you need to interpolate on to an irregular grid, both GSLIB and GSTAT (and so R) permit you to interpolate whatever set of points. Bye Sebastiano T. At 03.14 03/04/2007, Olumide wrote: Hello - (I'm relatively new to the subject and to the forum.) Are there any methods for kriging non-planar surfaces that have no natural parametrization e.g. a meteorite. Thanks, - Olumide + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/ + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/ + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/
Re: AI-GEOSTATS: Kriging a non-planar surface lacking natural parametization
Hi Sebastiano, I think Olumide's question was, what to do if the underlying manifold is not euclidean nor spheric or something regular of that kind. How would you define the distance beween pairs of points on the surface of a potatoe, or how would you lay a regular grid on a potatoe, which covers more than a local vicinity (which can be approximated planar or spherical) ? This is indeed by no means a trivial question, I think, well worth some thoughts of the geostats gurus I remember Gregoire Dubois has once suggested non-euclidean variography (defining distances which account for topography between the points). He is currently on hoildays, but he may have ideas about that. ciao, Peter sebastiano trevisani <[EMAIL PROTECTED]> writes: >Hi > >I'm not sure to understand what you mean when you say kriging on non >planar surface. >If you are saying that you need to interpolate on to an irregular >grid, both GSLIB and GSTAT (and so R) permit >you to interpolate whatever set of points. > > >Bye >Sebastiano T. > >At 03.14 03/04/2007, Olumide wrote: >>Hello - >> >>(I'm relatively new to the subject and to the forum.) >> >>Are there any methods for kriging non-planar surfaces that have no >>natural parametrization e.g. a meteorite. >> >>Thanks, >> >>- Olumide >>+ - Peter Bossew European Commission (EC) Joint Research Centre (JRC) Institute for Environment and Sustainability (IES) TP 441, Via Fermi 1 21020 Ispra (VA) ITALY Tel. +39 0332 78 9109 Fax. +39 0332 78 5466 Email: [EMAIL PROTECTED] WWW: http://rem.jrc.cec.eu.int "The views expressed are purely those of the writer and may not in any circumstances be regarded as stating an official position of the European Commission." + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/
Re: AI-GEOSTATS: Kriging a non-planar surface lacking natural parametization e.g. meteorite
Hi I'm not sure to understand what you mean when you say kriging on non planar surface. If you are saying that you need to interpolate on to an irregular grid, both GSLIB and GSTAT (and so R) permit you to interpolate whatever set of points. Bye Sebastiano T. At 03.14 03/04/2007, Olumide wrote: Hello - (I'm relatively new to the subject and to the forum.) Are there any methods for kriging non-planar surfaces that have no natural parametrization e.g. a meteorite. Thanks, - Olumide + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/ + + To post a message to the list, send it to ai-geostats@jrc.it + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/
