[OSM-talk] Surveying

[William Waites]

At 01:46 PM 11/19/2007, David James wrote:
>
>In the area I've been looking at, I've been trying to locate speed limit
>signs at the edges of villages, break the ways at the speed limit signs,
>and then apply appropriate maxspeed= tags to the separate ways. Am I
>wasting my effort here (as no-one else has yet mentioned speed limits).

Sounds useful, but perhaps there is a way to have much of this data with
less legwork. Suppose that we have municipal and village boundaries. We
know that the speed limit on the highway between villages tends to be
standard (say 110kmph) and that within villages tends to be lower (say
60kmph) but likewise standard. Is it not then possible to tag the
resultant segments with the appropriate maxspeed? It seems to me that
in this way the dataset could be populated to a quite high degree of
accuracy and completeness with relatively little data-entry work. Any
errors that are subsequently found could then be corrected by people
with more local knowledge and physical surveying capabilities as
necessary.

In the case that there are worries about having potentially incorrect
data, perhaps a tag such as maxspeed_bestguess=true could be applied to
such line segments until they can be confirmed, without compromising the
ability of route finding algorithms to function.

-w