Hi Jon, Indeed, the UM global climate model, for example, assumes a spherical earth.
In the absence of specific datum information I think I would probably caution against assuming any particular datum is applicable. I can understand the temptation to use WGS 1984 as a default because it is widely known and used. However, this implies a degree of accuracy in the coordinate data which in many instances may well not be justified - indeed its use might even compound any relative location errors. As you rightly suggest, if the end-use/application demands a particular spatial accuracy then any datasets which demonstrably do not not meet those requirements should probably not be included in the analysis - or else should be with appropriate caveats, provisos and disclaimers! Regards, Phil > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Jonathan Blower > Sent: 19 April 2010 16:23 > To: Mike Grant > Cc: [email protected] > Subject: Re: [CF-metadata] Default datum for latitude and longitude? > > Hi Mike, > > Yes, that's what I've been doing so far, but I seem to > remember someone telling me that models tend to be formulated > on a spherical earth. But maybe if the precise geolocation > of the model grid points is important (e.g. for small-scale > models) the datum will always be specified, or a different > projection used. > > Cheers, Jon > > -----Original Message----- > From: Mike Grant [mailto:[email protected]] > Sent: 19 April 2010 16:07 > To: Jonathan Blower > Cc: [email protected] > Subject: Re: [CF-metadata] Default datum for latitude and longitude? > > On 19/04/10 15:43, Jonathan Blower wrote: > > specification, which datum should be assumed? Spherical Earth? > WGS84? > > If you're picking one at random, I'd go for WGS84 - that's a > pretty safe bet for a lot of remote sensed and GPS related data. > > Cheers, > > Mike. > > -------------------------------------------------------------- > ---------- > -------- > Plymouth Marine Laboratory > > Registered Office: > Prospect Place > The Hoe > Plymouth PL1 3DH > > Website: www.pml.ac.uk > Registered Charity No. 1091222 > PML is a company limited by guarantee > registered in England & Wales > company number 4178503 > > PML is a member of the Plymouth Marine Sciences Partnership > Website: www.pmsp.org.uk > -------------------------------------------------------------- > ---------- > -------- > This e-mail, its content and any file attachments are confidential. > > If you have received this e-mail in error please do not copy, > disclose it to any third party or use the contents or > attachments in any way. > Please notify the sender by replying to this e-mail or e-mail > [email protected] and then delete the email without making > any copies or using it in any other way. > > The content of this message may contain personal views which > are not the views of Plymouth Marine Laboratory unless > specifically stated. > > You are reminded that e-mail communications are not secure > and may contain viruses. Plymouth Marine Laboratory accepts > no liability for any loss or damage which may be caused by viruses. > -------------------------------------------------------------- > ---------- > -------- > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
