The Montana Geographic Names Framework (MGNF) holds names and locations for cultural and geographic featues in Montana. For most features, this is the Federally recognized name from the Geographic Names Information System (GNIS). This is intended to include the names of all features, current and historical, that are shown on maps, except for roads and highways.The GNIS is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board on Geographic Names, a Federal inter-agency body chartered by public law to maintain uniform feature name usage throughout the Government and to promulgate standard names to the public. The GNIS is the official repository of domestic geographic names data; the official vehicle for geographic names use by all departments of the Federal Government; and the source for applying geographic names to Federal electronic and printed products of all types.The service includes a feature class with the primary point and State-recognized official name of each feature and two linked tables. One table contains the official names and additional alternate names for the features. The other table has descriptions and historical information for certain features which the Board on Geographic Names or State Library staff have worked with.The web service is provided in Web Mercator coordinates to make it compatible with online mapping applications. Distances and areas may not be measured accurately in this coordinate system and users must take steps to ensure that geodetic measurements are performed or that the data are converted to an appropriate coordinate system for making measurements in Montana. Linear measurements made in the Web Mercator coordinate system in Montana will result in values that are 40 to 50 percent too large.The MGNF was developed from the Montana GNIS text file, the national all_names file, and the national feature description file dated October 1, 2016 that were available on the USGS web site at http://geonames.usgs.gov/domestic/download_data.htm. The State Library has performed extensive edits to the data, which are described in the Supplemental Information section of this metadata document.
Each feature is represented in the Montana Geographic Names Framework (MGNF) feature class by its "primary point". A geographic feature may have only one primary point regardless of size or extent. The primary point of a linear feature depends on the feature class. If feature class equals stream, valley or arroyo, the primary point is the mouth. The primary point of a canal, channel, or trail is the center. The primary point of an areal feature is the approximate geographic center with the following exceptions: The primary point of a populated place is the center of the original place, if known, such as the city or town hall, main post office, or town square regardless of changes over time. The primary point of a reservoir may be the center of the dam that impounds it. The primary point of a summit, range, ridge, or pillar is the highest point. These points do not represent feature boundaries or geometries and should not be confused with them.
The GNIS contains over 20,000 un-named wells, mines, and springs that have been deleted from the MGNF.
The GNIS contains many features that are partially in Montana, but whose primary coordinates are outside of the state. In the MGNF, the coordinates have been moved to the nearest appropriate location on the state boundary.
Before 2005, features in the GNIS were assigned elevations if the GNIS staff noted an elevation printed on a topographic map. The current GNIS from USGS has an elevation for every feature, estimated from the National Elevation Dataset. In the MGNF, the estimated elevations have been replaced by the old map-based GNIS elevations where they were available. Additionally, many elevations, especially of mountain peaks, have been replaced by the elevations printed on 1:24,000 scale topographic maps.
The MGNF has many corrections in the names, feature classes, and locations of features that have been noted at the State Library. The MGNF features contain a value in the Change_Log field that indicate what sorts of edits have been performed on them.
The State Library and Montana Fish, Wildlife, and Parks (FWP) cooperated in 2012 to synchronize the GNIS with FWP's property database, which includes state parks, wildlife management areas, and fishing access sites. Scores of FWP properties which were not in the GNIS have been added to this data set, and the GNIS_ID field has been arbitrarily assigned values less than zero.