[OSM-talk] Azimuth measurement

[François Lacombe]

Hi,

Here is a topic discussed with a few people during State Of The Map FR last
week end in Paris.

Some features mapping would require to tag their azimuth as for knowing how
they are really installed in the environment.

For instance, benches mapped with nodes may be tagged with azimuth=*
because nodes don't tell which direction the bench follows.

But how contributors can measure it ?

Common devices like smart phones carry compass captors, used by compass
applications.
These captors only sense the magnetic north to determine the azimuth of the
device. The magnetic north is continuously diverting from the geographic
north.
Using the magnetic north isn't a good idea since the azimuth will be
continuously changing instead from the geographic azimuth.
There will be the same question regarding standard compasses.

Magnetic diversion is mathematically known and such azimuth could be
converted into geographic ones.

Is there a solution to that issue ?

Measuring geographic north directly isn't so simple I think.



Cheers.

*François Lacombe*

francois dot lacombe At telecom-bretagne dot eu
http://www.infos-reseaux.com
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