[Talk-us] NHD Dataset

Christopher Schmidt crschmidt at metacarta.com
Mon Feb 16 16:34:37 GMT 2009


On Mon, Feb 16, 2009 at 11:08:59AM -0500, Rev. Theodore Book wrote:
> I used a modified version of your MassGIS script - which did result in 
> some big ways.  I think we would need to find a faster way of uploading 
> if we wanted to complete the whole country in a reasonable length of time.

Which MassGIS script? mgis_to_osm, or the new polyshp2osm? The latter is
something I would recommend much more for anyone writing code now...
mgis_to_osm has some significantly convoluted stuff in it, in my reading
of it...

-- Chris

> Christopher Schmidt wrote:
> >On Mon, Feb 16, 2009 at 10:37:05AM -0500, Theodore Book wrote:
> >  
> >>I think it would be great to get it all in as soon as possible.  I do 
> >>see a few limiting factors, though:
> >>
> >>* In some places, a lot of work has been done manually entering water 
> >>features.  While I expect the NHD data is generally better, we have the 
> >>tough issue of respecting other people's work (and not duplicating 
> >>things in the database)
> >>
> >>* The upload speed seems to be a limiting factor - it is taking me some 
> >>70-80 hours to upload the one basis with bulk_upload.pl.  I am not sure 
> >>how many basins there are in the country, but it seems as though it 
> >>could take a year if it were all done sequentially.
> >>    
> >
> >If you're not uploading from dev.openstreetmap.org, there's probably a
> >significant speedbump to be gained from doing so. Additionally, once the
> >0.6 API is up, we can group a lot of changes into changesets: a *huge*
> >chunk of the time spent when uploading remotely is spent on round trip
> >to the server, nothing else. 
> >
> >  
> >>* The scripts I used to convert the shapefiles to OSM only supported the 
> >>features I found in this one basin.  They should be easy to extend, (or 
> >>someone else may have better ones), but they would need to be tested.
> >>    
> >
> >What script did you use for doing the polygons themselves? Did i t
> >support splitting of large polygons into smaller ways?
> >
> >Regards,
> >  

-- 
Christopher Schmidt
MetaCarta




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