[Talk-us] Planning to import NHD data for VT's White River (Subbasin 01080105). Seeking advice on making import community friendly.

[Josh Doe]

On Fri, Feb 10, 2012 at 7:22 AM, Josh Doe <josh at joshdoe.com> wrote:
> On Thu, Feb 9, 2012 at 10:43 PM, Scott <probiscus12 at gmail.com> wrote:
>> Hello All,
>>
>> I have been working on preparing the Natonal Hydrography Dataset (NHD -
>> There's an OSM wiki page for this source) data for the White River
>> (http://www.openstreetmap.org/?lat=43.68435&lon=-72.3982&zoom=16) in Vermont
>> for import to OpenStreetMap. In general, this seems to be a good candidate
>> for import, as there has not been a lot of work done in mapping the water
>> features in this region.
>>
>> I have read the NHD wiki pages as well as the pages on importing. I have in
>> particular read that imports can be detrimental to the OpenStreetMap
>> community, and would like to do my best to reduce and/or avoid this affect
>> as best as I can. I think the most important thing I can do is to try to
>> make sure the results follow K.I.S.S. principles, so here is what I am doing
>> so far:
>>
>> - Features have been simplified before conversion to OSM to remove many
>> excessive points, particularly in small streams.
>> - Split areas into what I think are manageable chunks. No ways with > 350
>> nodes, 5 ways > 300 nodes, < 20 ways with > 200 nodes. I have double
>> verified that the Shapefile to OSM conversion tool does not introduce
>> duplicate nodes.
>> - A minimum of unnecessary tags will be used. Tags common to the entire
>> dataset will instead be placed on the dedicated import users' wiki page.
>> - Multipolygon relations with only outer ways have been substituted with
>> single closed ways/areas.
>>
>>
>> Additionally, I have
>> - sent messages to all users who have added potentially conflicting
>> water/river features in the area I will be importing to. The responses I
>> have received thus far have been basically positive or neutral.
>> - taken note of the few features which would potentially overlap in NHD and
>> am taking steps to avoid uploading those parts of the data, in favor of
>> keeping user mapped features.
>> - checked my converted OSM data against both the Bing aerial imagery and the
>> OpenStreetMap/Mapnik tiles available in JOSM to ensure that the data makes
>> sense and that rivers will not overlap roads, etc.
>> - kept a record of the process I am following, to be placed on the dedicated
>> users' wiki page.
>>
>>
>> So, basically I am looking for thoughts and advice on how to ensure this
>> import will be a success, not just after importing, but in the future. I am
>> particularly interested in pointers on how to best facilitate future
>> modifications and enhancements by other mappers and myself.
>
> Sounds to me like you've done an excellent job, going above and beyond
> what most do. I would suggest you post your process on the wiki now,
> and put the converted/modified files online somewhere for review, like
> on Dropbox. I'm not sure what you are asking about "how to best
> facilitate future modifications and enhancements", whether in regards
> to the import process or the OSM data itself.
>
>> Additionally, I would be happy to make my converted and modified data
>> available to someone for review, if any one is interested.
>
>  If you don't have Dropbox or any webspace I can put them up for you.

I took a look at the files you sent me, and they seem in good shape.
Certainly the geometry isn't perfect in places, but it's definitely
good enough to use IMHO. It can be fairly easily refined over time,
using the ImproveWayAccuracy tool in JOSM to make the process much
easier and faster. I'd say go for it and then send us a list of the
changesets.

-Josh