[Imports] NHD Data Import

Kevin Kenny kevin.b.kenny at gmail.com
Sat May 8 18:32:17 UTC 2021


On Sat, May 8, 2021 at 2:11 PM <grussausbw at gmx.de> wrote:

> Hello, i'm Hiausirg (https://www.openstreetmap.org/user/Hiausirg)
> I've been mapping along railroad tracks for the last few weeks, and I've
> noticed that there are a lot of missing lakes/ponds etc. in the rural
> areas. Drawing them manually is very time-consuming, so I thought that it
> would be faster with an NHD
> <https://wiki.openstreetmap.org/wiki/National_Hydrography_Dataset>
> import.
> For this purpose, I have selected a smaller data set (compared to others)
> in the area in which I am currently editing, and prepared it for import. This
> is the data set
> <https://www.sciencebase.gov/catalog/item/5a58a424e4b00b291cd68491>. I
> have imported it into JOSM and prepared it for import. I converted all USGS
> tags to OSM tags, matched everything with current aerial images, deleted
> non-existing stuff, and so on. Every water spot/swamp was checked MANUALLY.
> Then I matched it to already existing data. There were about 500 lakes in
> the area, with my import there would be ~3000. 137,000 total objects
> (Nodes/Areas) would be added, 6200 deleted (these would be replaced with
> higher quality NHD data).
>
>
> In a nutshell: The data is high quality and I just have to press the
> upload button. After all, NHD data was uploaded ten years ago *and *i
> reviewed everything manually: Do I need to do anything else now except wait
> for an ok here? And should i create a seperate account to do this?
> By the way: Here
> <https://www.mediafire.com/file/3wnr6d02w4w5r2l/NHD.osm/file> is the data
> that *i* want to upload.
>
>
We don't import NHD data at scale "hands off", simply because the project
was started and proved to be a disaster - very poor data quality and issues
with connectivity - streams did not connect with their downstream
neighbours, were mapped opposite the direction of flow, and so on

If you're using a tool such as JOSM to do the uploads, you keep the uploads
to a manageable scale, and you are indeed reviewing all the data manually
and applying the validation checls, then there really are no issues.   NHD
is a public-domain US Government data source, so there are no legal
worries, and onesy-twosie copy-and-paste operations aren't really what the
import guidelines have been addressing.

Note that all this is just my opinion.  There are others - especially in
your country -  who believe that hand-crafted data are the only acceptable
data in OSM.  The US is a sufficiently large and sparse country that US
mappers will take our data wherever we can find them.


-- 
73 de ke9tv/2, Kevin
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