|Part of WikiProject United States.|
The USGS Geographic Names Information System (GNIS) is a database that contains millions of names for geographic features in the United States and Antarctica. The system is run by the Board of Geographic Names, a United States Geological Survey group. It is the authoritative set of geographic names for the US. It contains features that are on no other map or spatial database.
GNIS US data was bulk-imported in 2009 into OSM, and vast swathes of incorrect data still needs to be tracked down and corrected. The fundamental problem with GNIS is that it is a database of "names" and not "features" - if you want to answer the question "where is/was Foobar School" then GNIS will have a coordinate for that name and know that it is/was a school. Unfortunately GNIS records were imported into OSM without regard as to whether or not those features still exist, so there are tens of thousands of churches, schools, etc., that have long since disappeared - pre-dating the Interstate system in many (obvious) cases.
Editing GNIS Data
Removing historical features
If you come across a feature that no longer exists in the real world, feel free to delete it.
As of 2013, roughly 5% of the features in the GNIS database are designated as historical, typically meaning those features no longer exist. The GNIS name of historical features ends with "(historical)". Historical features were imported in 2009.
- Example: "Leschi Glacier (historical)" (Feature ID 1522032) was destroyed following the eruption of Mount St. Helens in 1980. It was imported as .
Not all former features have been designated historical yet in GNIS. Buildings, churches, schools, and hospitals frequently seem to be gone or still have old names in GNIS. The phrase "Junior High School" is still about as prevalent as "Middle School".
Converting GNIS Nodes to Areas
While the GNIS dataset includes only nodes, some of the features they represent are often better mapped as areas (e.g. islands, parks, buildings). When creating or editing an area that is also represented by a GNIS node, the GNIS tags should be copied to the area and the node should be deleted.
Merging Duplicated Nodes
Some GNIS imports have created multiple redundant nodes for a single GNIS feature. (Example: JOSM you can select the nodes and press "M" or go to Tools > Merge Nodes./ and other summits in that area.) If there's no need for two nodes, then copy the tags onto the node you wish to keep and then delete the unnecessary nodes. In
One of the positive features of using USGS's GNIS data set is that they offer a method of feeding changes, additions, and deletions back into the data set by the public. To facilitate this, all nodes were imported with the gnis:feature_id tag that corresponds to the FEATURE_ID column in the USGS database. This is their primary key and allows anyone to submit changes back to the website listed in External Links below. When merging a GNIS-tagged map feature in OSM with a duplicate feature, be sure to include the feature_id tag in the merged feature.
The Feature ID uniquely identifies a feature in the GNIS database and is thus the most important thing to tag when relating an OSM feature to a GNIS feature. The tag gnis:feature_id is by far the most commonly used for this purpose. Other tags for GNIS Feature IDs include gnis:id and tiger:PLACENS.
Sometimes these Feature IDs have leading zeroes. The online GNIS interface handles leading zeroes just fine.
Multiple GNIS features can be represented by a single feature in OSM. The semi-colon is most commonly used to list multiple IDs. In some cases these might be actual duplicates in the GNIS database (perhaps because the feature appears at slightly different coordinates on different maps).
There is a single FEATURE_CLASS column in the data set that is a key for the type of record and for the OSM tags that were applied.
|Swamp||natural=wetland + wetland=swamp|
|Building||Various tags based on building name, including|
Not all feature classes have been imported. Significant imports involving GNIS include:
- Many classes: The big 2009 import. More than a million features.
- "Stream" class: NHD imports have included the gnis:id tag (the Stream class was not imported in 2009).
- "Populated Place" class: Imported in 2007. See Changeset 85362 for one part of that.
- "Civil" class: From imports involving TIGER place boundaries with the tiger:PLACENS key. Done in 2009 (see Changeset 378277 as one small example). Commonly tagged on ways in some states and relations in others.
The 2007 import included a bunch of data:
- gnis:Class = Feature Class name
- gnis:County = County name
- gnis:County_num = County FIPS code
- gnis:ST_alpha = State name (2-Letter abbreviation)
- gnis:ST_num = State FIPS code
The 2009 import included:
- ele = GNIS data includes elevation
- gnis:county_id = County FIPS code
- gnis:created = MM/DD/YYYY when the GNIS entry was created
- gnis:state_id = State FIPS code
In some cases mappers have converted the GNIS county/state tags to is_in=* or addr=* format. Beware that GNIS tags often specify only one county/state per feature; if the feature crosses or forms a boundary, as many do, the GNIS tags may be insufficient to create proper is_in/addr tags.
- Example:  shows both counties, however only Kittitas is mentioned in feature's OSM tags. is part of the boundary between Kittitas and King counties in Washington. The associated GNIS Feature