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Subject: Re: [emergency] RE: Geo-GIS subcommittee call tomorrow.
Hi Jacob, Carl, All, Since we're having a GIS SC meeting today in about 20 minutes, I'll wait for the discussion, but RE:CAPv1.2, we have to maintain the 1.x compatibility. Moving forward, we need to expedite getting CAP 2.0 rolling with a full head of steam. There are a number of other efforts, as Carl notes, where we can help pull the ICT wagon in a good direction. Cheers, Rex Carl Reed wrote: > Jacob - > > Of course China uses GPS and deploys applications in which the WGS 84 > CRS is used. However, as in the US - and most countries for that > matter - many local, regional, and even national geo-applications use > other geoids and related CRSs. In the US, I would guess the vast > majority (all?) local governments use NAD 27/83 as the CRS of choice > for many layers (cadastral, surveyed street centerlines etc). There is > an interesting Datum Transformation diagram here > http://www.fs.fed.us/database/gps/aboutgps/documents/nad83.pdf > > As to accuracy of less than one meter, well, for example Australian > law mandates that cadastral data be good to well less than one meter. > Would your property lines to be off by a meter? And talk to any oil > company getting ready to drill a new well. Given the exacting > requirements of directional drilling and the distances drilled, > measuring the location (x,y and z) of the drill head to the most > exacting accuracy possible is more than just important. > > Precision is always an interesting issue, especially how to express > precision in terms of a standard. Just ask the IETF community. > > Regards > > Carl > > ----- Original Message ----- From: "Jacob Westfall" <jake@jpw.biz> > To: <emergency@lists.oasis-open.org> > Sent: Thursday, September 10, 2009 12:41 PM > Subject: Re: [emergency] RE: Geo-GIS subcommittee call tomorrow. > > >>> Also, there is the way outstanding issue regarding allowing >>> alternative coordinate reference systems. For example, the OGC is >>> working with the Chinese standards community to have a number of OGC >>> standards translated into Chinese. They require that all CRS >>> examples be in Xian80 and not WGS84. This is because Xian80 is the >>> China legal CRS and must be supported in any China standard dealing >>> with geo. >>> >> >> Regarding the CRS issue, a first question would be whether there is a >> need to support accuracy of less than 1 meter? Has precision >> surfaced as a problem for any users? For the chinese example, what >> is the actually legal requirement? How do they support >> interoperability with other countries for things like shipping and >> air traffic data? Don't they have to support WGS84 for civil >> aviation and satellite navigation? >> >> -- >> jake@jpw.biz >> -- >> >> --------------------------------------------------------------------- >> To unsubscribe from this mail list, you must leave the OASIS TC that >> generates this mail. Follow this link to all your TCs in OASIS at: >> https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php >> > > > --------------------------------------------------------------------- > To unsubscribe from this mail list, you must leave the OASIS TC that > generates this mail. Follow this link to all your TCs in OASIS at: > https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php > > -- Rex Brooks President, CEO Starbourne Communications Design GeoAddress: 1361-A Addison Berkeley, CA 94702 Tel: 510-898-0670
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