On 15/07/2015 17:16, François Lacombe wrote:
Thank you Dave,
2015-07-15 14:15 GMT+02:00 Dave Stanley <[email protected]
<mailto:[email protected]>>:
Hi
I map quite few radio sites in connection with my work. Usually it
is just mast/tower locations using the 'man_made=tower +
tower:type=communication' tags with name/operator information.
There are quite few things for these towers that could be
improved. For example the difference between a tower and a mast -
a mast in the UK is normally considered to have guy wires to hold
it up. where as a tower supports itself. May masts are big enough
to justify the guy wires being mapped with their ground anchor
points. I am not aware of anything suitable to do that.
Ok to say definitions and keys are a bit messy. It's only about
supports which can be refined independently.
There is also their feed line systems. I have used power=line to
map some of these, as in this example in Burma:
https://www.openstreetmap.org/#map=18/16.86624/96.16177
It is not ideal, but the closest I could think of. Medium-wave
broadcasts sites typically have very long feeder systems that can
be mapped, as in the example.
This is interesting
I didn't see the use of power=line like that but it can be adjusted.
Wouldn't you add frequency=* and usage=radio on such lines ? It may
allow consumers to distinguish them from standard electricity
transmission lines.
Certainly a tag like usage=radio or usage=rf would useful. Frequency
would be harder as often there are multiple or varying frequencies.
Something relating to size or diameter could also be relevant. These
lines can be physically quite large - big enough to be seen on the
satellite imagery for example.
RF can be used at high power rates : The CERN currently use them at
hundred of MW to power up its accelerator.
As for the antennas mounted on a mast/tower, you then may need to
consider the frequencies and operators that use the antennas. In
some cases there will be multiple frequencies and operators.
Physically, you would need the antenna height above ground level,
direction, possibly which leg it is on and so on.
Antennas have many characteristics but only a few are relevant in OSM.
It may be better to give a manufacturer name and model reference to
get such details directly from other databases.
Azimuth (if applicable), position and model information are the only
data required there, aren't you ?
Height and direction are most important. Probably some indication of
its overall size - maybe length. There could also be some indication of
the type of antenna, for example: yagi, dish, panel, reflector.
Regards
Dave
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