[Talk-GB] Quarterly task
John Aldridge
jpsa at cantab.net
Wed Jan 4 16:23:25 UTC 2017
Perhaps also worth trying to get the flow direction right.
http://tools.geofabrik.de/osmi/?view=water
can be helpful here.
--
Cheers,
John
On 04-Jan-17 15:22, Andy Townsend wrote:
> On 03/01/2017 22:34, Rob Nickerson wrote:
>> Water sounds good.
>
> ... and to me too - in fact it's what I've been doing on and off for the
> last couple of months, mainly in South Wales bordering areas that I've
> been walking where I've noticed that streams are in the wrong places.
>
> OS OpenData StreetView is quite predictable here - it's usually correct
> except in the following (checkable) situations:
>
> 1) a mountain stream has obviously moved (which you can see from Bing
> imagery, even if the latter is offset somewhat)
>
> 2) there's been some recent man-made intervention (e.g. a fishing lake)
>
> 3) it's a ditch beside a road - the OS tends to draw these in the
> "wrong" places for cartographical purposes, but again you can align via
> Bing, even if the latter is offset, because you can align the road.
>
> 4) the OS often adds a "catographic flourish" at the upper ends of
> mountain streams which in my experience (Black Mountain / Beacons /
> south of Hay) doesn't exist.
>
> 5) Sometimes the OS has the top ends of streams and ditches extending
> further than you might think (e.g. through a boggy area). That's the
> only one of these 5 that really needs surveying to check.
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