[Talk-us] dubious church node

Wolfgang Zenker wolfgang at lyxys.ka.sub.org
Sat Sep 30 17:54:15 UTC 2017


* Carl Anderson <carl.anderson at vadose.org> [170930 17:21]:
> ​A little history on GNIS data, and the Board of Geographic Names.

> The US Board of Geographic Names manages names for places and features
> shown on US govt maps.  They have been using a database to manage the names
> across maps and map scales. That database is the GNIS.

> The ​original GNIS data was populated from all text labels shown on USGS
> maps.  The most common source was 1:24,000 scale topo quarter quads.  Text
> from 1:100,000, 1:250,000 and 1:1,000,000 scale maps and larger were
> included.

> The stated map accuracy of these scales  (
> https://nationalmap.gov/standards/nmas.html ) is approximately

> 1:24:000        40 feet
> 1:250,000     416 feet
> 1:500,000     833 feet
> 1:1,000,000   1666 feet

> The GNIS dataset includes the most precise location for text, when the text
> appears on maps of different scales.

You can look at the full database entry for an individual GNIS feature
if you search for the GNIS Feature ID at geonames.usgs.gov/apex/f?p=gnispq

This will give you the source of the database entry, possibly a list of
alternate names, sometimes a note like "location approximate", and
sometimes the history of the decision process if more than one name
had been proposed for the feature. Also documentation of official
name changes.

One more thing to know about GNIS: entries are never deleted. If a
feature no longer exists, the name gets "(historical)" appended to
it. This may have happened after the feature was imported to OSM,
so it may not show in the OSM database.

Unfortunately the GNIS database is no longer fully maintained due to
budget constraints, so you can't be sure if features still exist even
if they are not flagged as "(historical)".

As to mapping in OSM: I usually remove any "(historical)" feature.
For the others, I improve the location if possible, and if the feature
can be represented as an area, I draw that area/polygon.
Instead of deleting the original POI, I now reuse that node as part
of the outline of the feature and only move the tags to the area, so
someone looking at the object details can notice that one of the nodes
is a lot older than the others and still find the osm history of the
feature on that node.

Wolfgang
( lyx @ OSM )



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