[Talk-us] USGS National Hydrography Dataset

[Alan Mintz]

At 2011-02-17 22:21, Toby Murray wrote:
>On Fri, Feb 18, 2011 at 12:09 AM, Val Kartchner <val42k at gmail.com> wrote:
> > On Thu, 2011-02-17 at 08:57 -0500, Phil! Gold wrote:
> >> (TopOSM also shows a lot of intermittent streams from the USGS National
> >> Hydrography Dataset.)
> >
> > Can we get this USGS dataset loaded?  It would be more accurate than
> > tracing from satellite images, and much quicker too.
>
>http://wiki.openstreetmap.org/wiki/NHD
>
>It has already been imported in some areas. Check the "Basins and
>per-basin sign-ups" section on the above page for details. There has
>not been an effort to do a nation-wide import though. As I understand
>it, the tools have been provided for local people to do it on their
>own. I have been meaning to look at this for Kansas...

Do look carefully at the results. In some places in the central/high 
deserts of CA, the NHD contained many thousands of poorly-connected streams 
that rarely seemed to correlate with actual features in surveys or 
satellite imagery. A lot of this is the nature of water in the desert - it 
tends to be very thin and to move around over time. The result was trouble 
with object density and download sizes, server throttling violations, all 
with no real benefit.

--
Alan Mintz <Alan_Mintz+OSM at Earthlink.net>