[Talk-us] Questions about bsupnik's NHD OSM files

[Paul Norman]

With all the address stuff I've completely dropped NHD off my plate.

 

I had been working on a NHD to OSM conversion and had gotten so far as to
get a Potlatch2 instance with it as a background layer, see
http://lists.openstreetmap.org/pipermail/talk-us/2012-November/009515.html
and http://took.paulnorman.ca/potlatch2/potlatch2.html.

 

The NHD data model changed shortly after bsupnik wrote his conversions and
some fcodes changed. This makes using his conversions difficult.

 

I would welcome a review of the tagging which I am proposing, which can be
found at
https://github.com/pnorman/ogr2osm-translations/blob/us_nhd/us_nhd.py. I can
also generate a .osm file for any sub-basin (4 digit code), or extract part
of a subbasin.

 

ogr2osm isn't too hard to run, but compiling ogr to have .mdb support to
open up the files from the USGS is difficult, so if you want me to convert
an area let me know the bbox and sub-basin.

 

From: Mack Stanley [mailto:mcs1937 at gmail.com] 
Sent: Monday, March 11, 2013 9:34 PM
To: talk-us at openstreetmap.org
Subject: [Talk-us] Questions about bsupnik's NHD OSM files

 

I have some questions regarding bsupnik's osm xml files made from the NHD
flowline, waterbody, line, and point shapefiles.    

I was very happy, belatedly, to find these files graciously created and
hosted by
bsupnik. Fall of 2011, I worked up some ogr2osm translations to do the same
thing
on shapefiles laboriously downloaded using the balky USGS National Map
Viewer,
unaware of bsupnik's work.

I've read a lot about the tagging and integration issues that make bulk
uploading
NHD data to OSM a bad idea.  My goal was just to use it to make a
hydrography
layer for my own use, while conforming to consensus tagging conventions,
potentially to make it useful to others.

I'd love to use bsupnik's files, instead.  My main problem is that GNIS
names of
streams and waterbodies aren't included.  I've seen this mentioned in this
list's
archives,  but couldn't find why this is, or how to fix it.  

I looked into adding name tags from GNIS feature files, but this looks more
or
less impossible. Names in feature files are attached to points.  The name
point
for a tributary is often at its confluence with the stream it feeds, making
the
name assignments difficult to determine mechanically. 

The rest of my questions are about tags. I've looked in detail at four files
(15010014, 16040201, 17090006, and 18040011). 

Three great things about bsupnik's files are that they are small, they are
easy to
read by humans, and the ultimate objects (points in point files, ways in
flowline
files, and relations in area and waterbody files) are tagged with their
fcodes.
This last feature means that other tags are frosting on the cake---it's
trivial to
rewrite with different tags. Bsupnik's wise preference seems to be to simply
leave objects without regular osm tags in cases where the correct tagging is
uncertain.

Nevertheless ...

In Flowline files, why is

fcode 33400 (connector) is tagged waterway:stream rather than waterway:canal
?

fcode 46000 (Stream/River no attributes) is not tagged, rather than
waterway:stream ? (Other Stream/River fcodes are tagged waterway:stream.)

fcode 46007 (Stream/River ephemeral) is tagged just waterway:stream, rather
than
waterway:stream intermittent:yes ?

In Waterbodies files, why is

fcode 39001 (Lake/pond intermittent) tagged natural:water
occurrence:intermittent, rather than natural:water intermittent:yes ?

All of the other intermittent tags that I have run across in the bsupnik nhd
files
follow the more common usage (judging by taginfo) intermittent:yes rather
than occurrence:intermittent.

fcode 46600 (Swamp/Marsh no attribute) is tagged natural:wetland, but
fcode 46601 (Swamp/Marsh intermittent) is not tagged, and
fcode 46602 (Swamp/Marsh perennial) is not tagged.

Why not tag all three natural:wetland with intermittent:yes added to 46601 ?

Thanks for your time and interest,

Mack

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