On 31/01/2015 1:47 AM, SomeoneElse wrote:
On 30/01/2015 14:12, St Niklaas wrote:
> From: François Lacombe <[email protected]>
>
> Since OSM editing tools aren't AutoCAD you can't be 100% precise on the
> geometry.
Exactly so.
Francois if you’re using JOSM you’re be able to work up till 0,06 -
0,04 =0,02 m accuracy
No. Unless you can measure accuracy on the ground to that level of
precision, you simply can't*.
And you should not use anything, AutoCAD included, to enter data at a
greater precision (accuracy) than what is available. Unfortunately the
data is stored as being absolutely accurate and precise so if the end
user is so inclined they could try to use it as such. They would quickly
be disappointed with OSM! OSM is not a source of absolute accuracy.
On 31/01/2015 1:47 AM, SomeoneElse wrote:
A good rule of thumb for OSM is "don't try and map more accurately
than your sources". If you only have aerial imagery, or only have a
few GPS traces, don't try and map every last hedgerow, since you
simply don't know how accurate the sources that you're working from
are. Instead, go out and collect more data. For example, once you
know how aerial imagery compares to lots of GPS traces (and vice-versa
- GPS traces can have a systematic offset due to terrain and even
"what side of a road people are allowed to walk down") you're in a
much better position to contribute.
Here I diverge. If the hedgerow is an improtant part of the landscape
then I'd map it .. even if it is not at your required level of
'accuracy'. Reason: it is the relationship between the objects on the
map that is important rather than the absolute accuracy of any one
object. If the relationship between the objects is representative of
what is on the ground then it conveys usefull information to the end
user and should be mapped.
_______________________________________________
Tagging mailing list
[email protected]
https://lists.openstreetmap.org/listinfo/tagging
