[Talk-us] NHD conversions to OSM

[Ben Supnik]

Hi Josh,

First: the wiki - I was planning to document the data once we had a 
final download location, either an official-ish OSM server or anything 
else we come up with.  I will update the wiki page once we know where 
the data will live
> I've also looked at the data, and I must say I'm confused! One river
> is represented in the flh file as waterway=stream, in arhi as
> waterway=riverbank, in flmd as waterway=stream (but with worse spatial
> accuracy than flh), and then in armd as waterway=riverbank!

Right - there are two resolutions in the NHD extracts the USGS sent me, 
medium and high.  I am stripping out the medium res ones per Ian's 
comments, which will make things more consistent.

> I suppose
> one of the waterway=stream's should be changed to waterway=river, and
> only one of the waterway=riverbank objects should be used.

Well, only one of the _layers_ should be used, e.g. all high or all 
medium, Ian saying all high.  Whether the waterway should be stream or 
river, I defer to others who have deep insights or strong opinions on 
such things; these extracts are based on a conversion key built by others.

> Is this really what the NHD data is like? It will take more time than
> I thought to properly merge these these 6 or 7 layers.

Well, once it's only high res, it's 5 layers that are spatially consistent.

cheers
ben