[Openstreetmap] OSM - Schema - Phase 1 - Request for Comment

[Andy Robinson]

All,

Ok, so some have had a little poke around at this already. Now its time to
do something so we can put it to bed for a while.

Starting with the data primitives, i.e. the root XML elements - this
discussion is not about whether XML is right or not.

Here is what I would suggest we limit this first discussion to cover.
Hopefully it's painless!

In the text below the <comment> tag is simply there for this discussion. The
following are the root elements that would make up an OSM Schema.

1. <wpt>
<comment> wpt as per GPX, ie representing "waypoint, point of interest, or
named feature on a map." The <wpt> element would be used to define all POINT
features in OSM</comment>

2. <rte>
<comment> rte as per GPX, not currently being used within OSM but with
obvious navigational use. Representing a "route - an ordered list of
waypoints [although deviate by changing <wpt> to <pt> here - see below]
representing a series of turn points leading to a destination." </comment>

3. <trk>
<comment> trk as per GPX, ie representing "a track - an ordered list of
points describing a path". Applying this only to GPS trails and not, for
instance, a street. </comment>

4. <pt>
<comment> pt as per GPX, ie representing "a geographic point with optional
elevation and time". This would replace the current OSM "<node>". </comment>

5. <ptseg>
<comment> ptseg as per GPX, ie representing "an ordered sequence of points.
(for polygons or polylines". We would restrict the use of this to two points
and use it to replace our current line segments. A minimum of three points
would be required for use as an area designator.</comment>

6. <way>
<comment> way would be the first of our two non-GPX global elements and
covers the unique flexibility we wish for a Street Map in that any number
and combination of <ptseg>'s can be included to form, for instance, a
street. The Way defines all LINEAR features in OSM, a typical list of linear
map features (for guidance) will appear in the next comment phase</comment>

7. <area>
<comment> area would be the second of our two non-GPX global elements and
covers the unique flexibility we wish for a Street Map in that any number
and combination of <ptseg> defined Areas's can be included. This allows
multiple individual areas to be combined in the same was as is possible for
Ways, for example so that a site that is split by another feature can be
described as a single element. The Area defines all AREA features in OSM.
</comment>

8. <bounds>
<comment> bounds as per GPX, ie representing "Two lat/lon pairs defining the
extent of an element". Essentially to provide a limiting bounding box as we
do now with the "bbox=" attribute</comment>


Some of the global elements from GPX have been deliberately left out on the
basis that these are generally likely to be sub elements within each of the
above global element sequences and we can further discuss the sub elements
and any sequencing issues later.


It would help enormously with processing and reaching consensus if you could
add your comments to the numbered list below rather than within the body of
the text above.

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

Anything else?


Feel free to respond to either list or myself. I've not set a time limit,
but will report back when it appears the major points have been aired.

Cheers,

Andy


Andy Robinson
Andy_J_Robinson at blueyonder.co.uk