EPSG systems

EPSG:4406 NAD27 / BLM 6N (ftUS)

Projected system (Transverse Mercator) in use: USA - 150°W to 144°W - AK, OCS. The full definition below, and conversion in one click.

System record
CodeEPSG:4406
NameNAD27 / BLM 6N (ftUS)
TypeProjected system — Transverse Mercator
Area of use USA - 150°W to 144°W - AK, OCS
United States (USA) - between 150°W and 144°W - Alaska and offshore continental shelf (OCS).
Bounds W -150,00° · S 54,05° · E -143,99° · N 74,13°
Countries United States
DatumNorth American Datum 1927
Ellipsoid Clarke 1866 a = 6378206.4 m · 1/f = 294.978698214
Base geographic system EPSG:4267 — NAD27
Unit US survey foot (X east, Y north)
Transformation to WGS 84 NAD27 to WGS 84 (7) (EPSG:1176) — accuracy 12 m
ScopeNo official usage.

Projection parameters

ParameterValueUnit
Latitude of natural origin0degree
Longitude of natural origin-147degree
Scale factor at natural origin0.9996unity
False easting1640416.67US survey foot
False northing0US survey foot

proj4 definition

+proj=tmerc +lat_0=0 +lon_0=-147 +k=0.9996 +x_0=500000.001016002 +y_0=0 +a=6378206.4000000004 +rf=294.9786982139 +units=us-ft +towgs84=-5,135,172 +no_defs

Paste it into QGIS, proj4js, PostGIS (spatial_ref_sys) or GDAL. +towgs84 carries the EPSG transformation to WGS 84; the official code stays EPSG:4406.

WKT (ESRI format, the .prj content)

PROJCS["NAD_1927_BLM_Zone_6N",GEOGCS["GCS_North_American_1927",DATUM["D_North_American_1927",SPHEROID["Clarke_1866",6378206.4,294.978698213898]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",1640416.67],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-147.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["US survey foot",0.304800609601219]]

All systems — United States

Source: EPSG registry v11.022 (IOGP), through the PROJ database. Always check a code on epsg.org before contractual work.