Hi,
we have this recurring topic in various parts of OSM - airspace
mapping.
I'm strictly against it.
(For those not familiar with airspace, here's an example of a VFR
airspace map:
http://www.rc-network.de/magazin/artikel_02/art_02-0001/ICAO-Karte-Ausschnitt-Bild2.jpg)
My arguments against airspace mapping are:
1. Imports of un-observable things that are defined by other people
should be kept to an absolute minimum in OSM. Airspace definitions
change regularly and the only way to have them in OSM is to import them
again and again.
2. Airspace (since it only rarely has any connection to features on the
ground) is perfectly suited for an overlay; very little would be gained
by having it in OSM rather than in a parallel system maintained by a
flying enthusiast.
3. For the same reason, airspace boundaries cut right across the
country, through cities, and so on, and provide an unnecessary
distraction to mappers.
4. 99% of Airspace is of almost no significance to non-pilots. Arguments
like "one would like to know if the house one intends to buy is within
some kind of airspace" are fantasy.
5. Pilots would not use a crowdsourced airspace map; they are legally
required to have a current official map anyway when they fly somewhere.
It seems to me that people who would like to have airspace in OSM are
mostly flight simulator aficionados, and while I find that an
interesting pastime, one has to be honest about it: Flight simulators
are computer games.
6. The usual form in which airspace is published is on printed,
copyrighted maps; it is difficult, if not impossible, to actually get
your hands on airspace descriptions that are official and not copyright
encumbered.
There was limited discussion here recently:
http://help.openstreetmap.org/questions/3684/mapping-for-aviation
although this question was a little broader, concerning not only
airspace but also other aviation-related items such as beacons. My
position in that discussion was: If a feature is observable on the
ground and doubles as an aviation reporting point - no problem, tag it.
But if something is defined just by its coordinates or a mark on an
airspace map - don't.
The beast rears its head in this "proposed feature" from 2009
http://wiki.openstreetmap.org/wiki/Proposed_features/Airspace
and in its German counterpart,
http://wiki.openstreetmap.org/wiki/DE:Luftraum
and on
http://wiki.openstreetmap.org/wiki/Aeroways
the topic is briefly referenced. Also there was discussion about
aviation tracks on help.osm last year:
http://help.openstreetmap.org/questions/297/does-it-make-sense-to-upload-aviation-tracks-to-osm
There are currently 21 "airspace" objects in OSM.
I would like to end this discussion once and for all, or at least for
the near future, and create a wiki page named "Aviation", to which I
would link from the "Aeroways" page and from "Airspace", and I would
also close the "Proposed Feature" with a link to that page.
On the "Aviation" page, I would write up the reasons against airspace
mapping, basically as given above and on the "mapping-for-aviation" help
page, concluding that mapping for aviation is discouraged
On that page I would also suggest that someone who is reasonably
interested should set up a rails port instance of their own, complete
with a rendering chain to generate half-transparent tiles that can be
overlaid over a standard map. And I would even offer them my help in
doing that.
But before I do all that, I would like to hear from the community at
large - you - whether you share my view. Do you agree that airspace
should be elsewhere but not in OSM? Or do you think that airspace should
have a place in OSM after all?
Bye
Frederik
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