Talk:Geodetic system
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Agreed Budgiekiller 14:45, September 1, 2005 (UTC)
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[edit] Datum Merged
The article Datum has been successfully merged into this article. Also there is a proposed plan to merge this article into Geodesy. I agree to merge this article into the sub-section in Geodesy called Geodetic datums. --Zer_T 01:35, 16 December 2005 (UTC)
[edit] Datums
As I am not a cartographer I will not edit the page. More than one datum requires the plural, which is data. Reg nim 20:40, 19 December 2006 (UTC)
[edit] Geoid plus other references required =
There should be discussion of the GEOID in this article for better background. Also, there are several publically available documents, and spreadsheets enabling the conversions from XYZ to Lat Long Height. (polar coords, with deference to the ellipsoid)
references to Peter Dana's other work would be useful
http://www.colorado.edu/geography/gcraft/notes/coordsys/coordsys_f.html
14:50, 3 April 2007 (UTC)
[edit] Great article: need addition to formulae sections
It would be helpful to add a note to the sections with the geodetic-geocentric-cartesian transformations to indicate what % of error is introduced by the equations. Users will then know whether they can expect tranformations using these formulae to be accurate within 1m, 1cm, etc. DiscipleOfChrist 16:37, 15 May 2007 (UTC)
[edit] Geodetic vs Geocentric latitude
Whether is clear the definition of Geodetic and Geocentric latitude and the related conversion formulas, it is not clear which of the two definitions is assumed as reference for the WGS84 standard. In the pdf (linked to this page) describing the standard, both definitions are used for different computations. It seems that in all computations related to gravity, the geocentric latitude is more convenient than geodetic, where in all local computations related to targets localization the geodetic one is mostly used, likely because targets which share the same projection on the (ellipsoidal) Earth surface but having different altitudes, will not change their latitude, leaving the independency among the Lat/Long coordinates and the Altitude. However, it is elsewhere reported that the GPS (based upon the WGS84) does use the geocentric latitude definition. Someone knows specifically (apart from the obvious remark that the World GEODETIC system should follow Geodetic Lat/Long coordinates) which is the official Lat/Long definition for WGS84? 81.208.53.251 12:50, 31 July 2007 (UTC)Paolo, Rome 31-07-200781.208.53.251 12:50, 31 July 2007 (UTC)
[edit] Which latitude is which?
In all navigation applications (including GPS) latitude is geodetic latitude. This is because geodetic latitude is measured with respect to the horizon whereas geocentric latitude is requires knowledge of the centre of Earth (not really possible for a ship at sea). Moreover if you measure the angle between the pole star and the horizon (something we can not do in the southern hemisphere!) you can determine your geodetic latitude. The navigator will drop the term geodetic and just say latitude. Hope this helps. —Preceding unsigned comment added by 192.43.227.18 (talk) 09:48, 7 September 2007 (UTC)
