[Talk-us] hyrdography imports
steve at asklater.com
Wed Feb 10 15:59:15 GMT 2010
On Feb 10, 2010, at 8:48 AM, Mike N. wrote:
>> any way the importer can
>> a) go back and fix all the millions of duplicated nodes
>> b) not do it in future?
> I'm working on both points -
> a) Happens in several cases:
> 1. At the joining of streams to waterbodies. The duplicate happens
> because data comes from 2 separate sources (Flowlines and Waterbodies /
> Areas). There needs to be a higher level view to combine them. The number
> of duplicates is relatively small.
> 2. NHD features are placed into multiple NHD 'sub-basin extracts'.
> Those could be eliminated at OSM conversion time if the conversion scripts
> were to have access to all features previously imported. This can result
> in many duplicates.
> 3. Adjoining area types from NHD do not share nodes, but should. I was
> able to cobble together a manual Perl script to fix this up as features are
> imported, but it's not a good general solution.
is this covered - it seems to happen at every single stream intersection?
> b.) All current scripts I know of require significant rework, short of
> importing the NHD into a local GEO database, then exporting it to remove
> duplicate nodes.
> Should we halt all US Hydro import work until this is resolved?
personally I think so, I'm fixing stuff in CO just to get a feel for it
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