geo-extension-waypoints

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Revision as of 18:59, 7 September 2007 by AndyMabbett (talk | contribs) (Tools: GPS Visualizer)
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Geo Waypoint Trails

An exploration of publishing information about sequences of geographical points using series of Geo (or other) microformats.

Terms

Conceptually, a collection of points, with no sequential relationship (the county towns of England, say, or all skyscrapers in New York), is deemed a collection (or set) of individual Waypoints. A sequentially-ordered collection of points may be expressed as a track or a route. Tracks are a record of where a person has been, routes are suggestions about where they might go in the future. So, for instance, there might be timestamps for each point in a track (because someone is recording where and when they were there), but timestamps for each point in a route are unlikely to be provided, because the author is suggesting it, and nobody might ever have travelled it.

A route which ends at its beginning may also describe a boundary (also called a box or polygon). A boundary may be for an object or area on any scale, from a small building or plot of land to a continent, at any level of granularity.

It may therefore be appropriate to use a sequence of hCalendar microformats for tracks and of hCard microformats for routes, boundaries and waypoints.

The Problem

To allow the publishing of series of waypoints in such a way that they are downloadable and that their ordering is parsable.

Participants

Real-World Examples

Collections

  <tr>
  <td>10</td>
  <td>
    <div class="geo">
      <span class="latitude">52.38616</span><br/>
      <span class="longitude">4.91199</span>
    </div>
  </td>
  <td ><a href="...">Waypoint 10</a></td>
  <td >Amsterdam (3 km) <a title="" href="...">Map</a></td>
  </tr>

Other

  <wpt lat="39.921055008" lon="3.054223107"> 
  <ele>12.863281</ele> 
  <time>2005-05-16T11:49:06Z</time> 
  <name>Cala Sant Vicenç - Mallorca</name> 
  <sym>City</sym> 
  </wpt>

Existing formats

A number of other formats (which route/ track parsers may wish to export) are listed at http://www.gpsbabel.org/capabilities.html

Tools

  • GPS Babel is a free command line utility (there is a GUI, but it has limited functionality) for converting between these formats.
  • GPS Visualizer reads a variety of GPS formats

    including but not limited to: GPX, OziExplorer, Geocaching.com (.loc), IGC sailplane logs, Garmin Forerunner (.xml/.hst/.tcx), Timex Trainer (v1.3+), Cetus GPS, PathAway, cotoGPS, CompeGPS, TomTom (.pgl), IGN Rando (.rdn), Emtac Trine, Suunto X9/X9i (.sdf), NetStumbler/WiFiFoFum, GPSManager, MS Excel, and of course tab-delimited or comma-separated text

    and converts them, maps them, or outputs a graphical representation.

Typical mandatory attributes

  • Latitude (WSG84, using decimal or degrees-minutes-seconds values)
  • Longitude (ditto)
  • text label

Typical optional attributes

  • timestamp
  • elevation
  • image
  • note ?
  • url ?

Issues

  • How to indicate that a set of waypoints is a specific, but unordered, collection (i.e. a set of all the metro stations in Paris, and another set of all the underground stations in London, may be published on the same page)
    • KML uses "Folder" for each such set. e.g [1]
  • How to sequence routes
    • Perhaps using order in source code, ordered lists, hCalendar or hAtom?
    • We could use hAtom and the feed category to distinguish between ordered, unordered and polygons.
      • hAtom requires both an author and date, neither of which are required for routes or polygons. Andy Mabbett
  • How to timestamp tracks (timestamps imply a chronological sequence)
  • How to differentiate between a route (for example in the shape of a letter "U") and a boundary (or polygon) - in other words, to say whether or not, after the last point, the line returns to the first.
    • Suppose we use class="folder" for a sequence (per KML; see above). We could have class="folder route" or class="folder polygon".
  • What can we learn, or use, from the GPX (XML schema for GPS data) specification?

References

See Also