[Talk-us] GNIS Import Done
Eric Wolf
ebwolf at gmail.com
Fri Mar 13 14:46:19 GMT 2009
Much of the GNIS data was extracted during the scanning and color
separation of the 1:24K 7.5' topo sheets. Those maps were made from
survey information - not GPS or satellite. And, because those were
hand made maps, cartographic convention sometimes required things to
be shifted. However, landforms - like peaks would have been the last
to shift.
The USGS usually has published accuracy standards. Unfortunately, GNIS
defaults to the accuracy standards of the input data:
http://geonames.usgs.gov/domestic/metadata.htm#quality.2
While GNIS might not be perfectly accurate in geoposition, it is the
authoritative set of geographic names for the US. It contains features
that are on no other map or spatial database.
-Eric
-=--=---=----=----=---=--=-=--=---=----=---=--=-=-
Eric B. Wolf 720-209-6818
USGS Geographer
Center of Excellence in GIScience
PhD Student
CU-Boulder - Geography
On Fri, Mar 13, 2009 at 12:41 AM, Apollinaris Schoell
<aschoell at gmail.com> wrote:
> How accurate is this data and how does it fit match with USGS maps? Just
> checked one Peak I had entered some time ago.
> USGS map 9735ft =2967m, GNIS import 2965m & position shift ~20m (Garmin
> TopoUS 2008 2964m)
> position of USGS map and Yahoo matches exactly with my gpx tracks.
>
> Interesting to see USGS must have different data. And like in many other
> cases Garmin has the wrong data ....
>
>
> On Thu, Mar 12, 2009 at 6:29 AM, Ian Dees <ian.dees at gmail.com> wrote:
>>
>> Hi everyone,
>>
>> I completed the GNIS node import yesterday. Please see the wiki page [1]
>> for more details.
>>
>> As several of you have messaged me and posted on this list, there are some
>> problems with this data. Let me try to explain my thought process:
>>
>> 1. Since the resolution of the information is fairly low (i.e. a clinic,
>> hospital, doctor's office, retirement home, etc. are all tagged "hospital"
>> in their data set), I have absolutely zero problem with retagging data if
>> you come across a feature that is incorrectly tagged. Not like you need my
>> approval, but that higher resolution of info might convince the GNIS board
>> to add some more tags to their data set.
>>
>> 2. I'm planning on taking the planet dump and grepping out all of the GNIS
>> data. This will be used to generate diffs that we can send back to the GNIS
>> board, who has the option of putting it back into their data set.
>>
>> 3. If there are already OSM features in your area for a certain node that
>> I imported, feel free to delete my node, but please merge at least the
>> gnis:feature_id tag from the GNIS data so that we can keep track of future
>> name changes.
>>
>> -Ian
>>
>> [1] http://wiki.openstreetmap.org/wiki/USGS_GNIS
>>
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