geo-extension-nonWGS84

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Revision as of 14:53, 17 December 2006 by AndyMabbett (talk | contribs) (→‎Notes: correction (pending firther clarification on mailing list))
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Geo Extension Straw-Man Proposal

Further to proposals for luna and mars equivalents to Geo, the following is a "straw-man" proposal, to incorporate those ideas (and likewise for other bodies) into geo, in order that further debate may take place. Please feel free to critique it harshly but fairly!

Author

Andy Mabbett

Straw-Man

<span class="geo">

  <span class="body">
    Mars [1]
  </span>

  <span class="schema">
    [name of mapping schema] [2]
  </span>

  <span class="latitude">37.386013</span>, 
  <span class="longitude">-122.082932</span> [3]
</span>

Notes

  1. A list of acceptable, case-insensitive, values for 'body' would need to be drawn up (e.g. "Earth", "Mars", "Luna", "Venus", etc.) wither "Earth" being assumed if none is specified.
  2. A list of acceptable values for 'schema' would need to be drawn up, for each body, with one being declared the default, to be used if no value is present (geo for Earth uses the datum of WGS84).
  3. As currently with geo, if the "latitude" and "longitude" classes are omitted, the two values MUST be separated by a semi-colon and latitude MUST be first:<span class=geo">37.386013,-122.082932</span>
Also:
  • If latitude is present, so MUST be longitude, and vice versa.
  • The same number of decimal places SHOULD be used in each value.
  • The Gazetteer of Planetary Nomenclature has coordinates for other planets, e.g. Venus and moons, e.g. Io.

Issues

  • Should other bodies be included in geo, or have stand-alone microformats?
  • What effect will this have on existing 'geo' parsers, and it is safe to ignore that?
  • What appropriate schemas exist?
    • Lunar: Mean Earth Polar Axis
    • ??
  • Luna is the scientific name for Earth's moon. Should we use that, or reserve "Moon"?
  • Is it appropriate to use the name "geo" (which means "Earth") for other bodies?
  • is body an acceptable class name, given that it's also an HTML element?

Comments

thare

Comments from thare

  • geo does stand for Earth but it has previously been generalized for the planetary case. For example, the term geology is used for planetary bodies.
  • using body is fine by me and do not see a conflict as an HTML element.
  • by schema do you mean a natural surficial property like earthquake, volcano, or crater? Or do you also want to include man-made items building, house, landing site?
    • No, I mean, for example, WGS84, or the Martian or lunar equivalents. Is "schema" perhaps the wrong word?. Andy Mabbett
  • I would suggest just using "Moon". For other spellings for planetary bodies I would look toward the IAU/IAG documentation (an international working group) IAU/IAG Working Group (WG) on Cartographic Coordinates and Rotational Elements
  • Since this is a simple case, I tried to stay away from this issue but just can't. What does Earth really mean? There a many definitions for the size of Earth that need to be resolved when using lat/lon coordinates. Is the size of the Earth defined by the WGS84 or NAD27 definition? For Mars, is it the definition used in 1991 or redefined in 2000? This has previously been solved in web GIS applications by using an "EPSG" code. For planetary bodies we are attempting to define a similar coded standard which currently is called the IAU2000 code or namespace. Thus for Mars the code might be IAU2000:49900.
  • still working - more later

Other

  • ???