[Talk-us] What to do with unnamed NHD streams

Paul Norman penorman at mac.com
Mon Oct 29 07:59:09 GMT 2012

> From: Michal Migurski [mailto:mike at teczno.com]
> Subject: Re: [Talk-us] What to do with unnamed NHD streams
> On Oct 29, 2012, at 12:03 AM, Michal Migurski wrote:
> >>> Do you have any sample NHD extracts that might be usable for a test
> >>> drive?
> >>
> >> All of NHD can be found at on the USGS FTP site, but you need to
> >> compile gdal with 3rd-party toolkits to be able to use them. This is
> >> quite often a pain.
> >>
> >> I clipped out a small part of Kansas I was testing with early,
> >> converted it to a set of shapefiles and posted it at
> >> http://took.paulnorman.ca/imports/NHDH0202_shp.zip
> >>
> >> I should note that some information is lost in the shapefile
> >> conversion (long field names).
> >>
> >> For space reasons I dropped the WBD_HU layers. The first step of my
> >> converting is to remove them anyways.
> >
> > Awesome, downloading!
> Yum:
> 	https://dl.dropbox.com/u/30204300/NHD.png
> I can see that the water areas are also represented as centerlines, how
> would you import these?

What's been recommended for rivers is to have both a waterway=riverbank
(although some people prefer natural=water) for the water area and a
waterway=river down the middle. I carry the same convention to small and
medium lakes where it makes sense. Some lakes don't have a clear flow to
them in which case it doesn't make sense.

For NHD this means applying the same logic to FCode 55800 ARTIFICAL PATHs as
to 4600x STREAM/RIVERs, done with

55800 ARTIFICAL PATHs are not be confused with 33400 CONNECTORs, which I

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