Phase 1 lasted from 1978 to 1981, with a precursor pilot project run over the states of Kansas and Colorado in 1976, and produced 5 databases. It excluded several classes of feature because they were better documented in non-USGS maps, including airports, the broadcasting masts for radio and television stations, civil divisions, regional and historic names, individual buildings, roads, and
triangulation depot names. The databases were initially available on paper (2 to 3
spiral-bound volumes per state), on
microfiche, and on
magnetic tape encoded (unless otherwise requested) in
EBCDIC with 248-byte fixed-length
records in 4960-byte
blocks. The feature classes for association with each name included (for examples) "locale" (a "place at which there is or was human activity" not covered by a more specific feature class), "populated place" (a "place or area with clustered or scattered buildings"), "spring" (a
spring), "lava" (a
lava flow,
kepula, or other such feature), and "well" (a
well).
Mountain features would fall into "ridge", "range", or "summit" classes. A feature class "tank" was sometimes used for lakes, which was problematic in several ways. This feature class was undocumented, and it was (in the words of a 1986 report from the Engineer Topographic Laboratories of the
United States Army Corps of Engineers) "an unreasonable determination", with the likes of
Cayuga Lake (in upstate New York) being labelled a "tank". The USACE report assumed that "tank" meant "reservoir", and observed that often the coordinates of "tanks" were outside of their boundaries and were "possibly at the point where a dam is thought to be".
National Geographic Names database The
National Geographic Names database (NGNDB hereafter) was originally 57 computer files, one for each state and territory of the United States (except Alaska which got two) plus one for the District of Columbia. The second Alaska file was an earlier database, the Dictionary of Alaska Place Names that had been compiled by the USGS in 1967. A further two files were later added, covering the entire United States and that were abridged versions of the data in the other 57: one for the 50,000 most well known populated places and features, and one for most of the populated places. The files were compiled from all of the names to be found on USGS topographic maps, plus data from various state map sources. In phase 1, elevations were recorded in
feet only, with no conversion to metric, and only if there was an actual elevation recorded for the map feature. They were of either the lowest or highest point of the feature, as appropriate. Interpolated elevations, calculated by
interpolation between
contour lines, were added in phase 2. Names were the official name, except where the name contained
diacritic characters that the computer file encodings of the time could not handle (which were in phase 1 marked with an asterisk for update in a later phase). Generic designations were given after specific names, so (for examples)
Mount Saint Helens was recorded as "Saint Helens, Mount", although cities named
Mount Olive, not actually being mountains, would not take "Mount" to be a generic part and would retain their order "Mount Olive". The primary geographic coordinates of features which occupy an area, rather than being a single point feature, were the location of the feature's mouth, or of the approximate center of the area of the feature. Such approximate centers were "eye-balled" estimates by the people performing the digitization, subject to the constraint that centers of areal features were not placed within other features that are inside them.
alluvial fans and
river deltas counted as mouths for this purpose. For cities and other large populated places, the coordinates were taken to be those of a primary civic feature such as the
city hall or
town hall, main
public library, main highway intersection, main post office, or
central business district regardless of changes over time; these coordinates are called the "primary point". Secondary coordinates were only an aid to locating which topographic map(s) the feature extended across, and were "simply anywhere on the feature and on the topographic map with which it is associated". River sources were determined by the shortest drain, subject to the proximities of other features that were clearly related to the river by their names.
USGS Topographic Map Names database The
USGS Topographic Map Names database (TMNDB hereafter) was also 57 computer files containing the names of maps: 56 for 1:24000 scale USGS maps as with the NGNDB, the 57th being (rather than a second Alaska file) data from the 1:100000 and 1:250000 scale USGS maps. Map names were recorded exactly as on the maps themselves, with the exceptions for diacritics as with the NGNDB. Unlike the NGNDB, locations were the geographic coordinates of the south-east corner of the given map, except for
American Samoa and
Guam maps where they were of the north-east corner. The TMNDB was later renamed the
Geographic Cell Names database (GCNDB hereafter) in the 1990s.
Generic database The
Generic database was in essence a machine-readable glossary of terms and abbreviations taken from the map sources, with their definitions, grouped into collections of related terms.
National Atlas database The
National Atlas database was an abridged version of the NGNDB that contained only those entries that were in the index to the USGS
National Atlas of the United States, with the coordinates published in the latter substituted for the coordinates from the former.
Board on Geographic Names database The
Board on Geographic Names database was a record of investigative work of the USGS
Board on Geographic Names' Domestic Names Committee, and decisions that it had made from 1890 onwards, as well as names that were enshrined by
Acts of Congress. Elevation and location data followed the same rules as for the NGNDB. So too did names with diacritic characters. == Phase 2 ==