Interior

Township GeoCoder Web Service

Interior uses the GeoCommunicator GeoCoder Web Service provided by the US Department of the Interior. For detailed documentation on the web service API, consult the Methods, Parameters, and Results PDF.

Usage: Get Latitude / Longitude

Given township 1N, range 1E, section 35, and meridian 14 (Gila-Salt Meridian in the US Meridian table), we can get the center point latitude and longitude in the state of Arizona with:

require 'interior'
response = Interior::Geocoder.get_lat_lon('AZ', 14, 1, 'N', 1, 'E', 35)
response.success?   => true
response.latitude   => 33.384549272498
response.longitude  => -112.228362739723

Section is option. If omitted, the centerpoint latitude and longitude will be for the township and range:

require 'interior'
response = Interior::Geocoder.get_lat_lon('AZ', 14, 1, 'N', 1, 'E') # no section
response.success?   => true
response.latitude   => 33.4211630233451
response.longitude  => -112.254699834217

Usage: Get Meridians

For a collection of all meridians in Arizona:

require 'interior'
meridians = Interior::Geocoder.get_meridians('AZ')
meridians.inspect
  => [ { :name => 'Gila-Salt River', :id => 14 },
       { :name => 'Navajo',          :id => 22 },
       { :name => 'San Bernardino',  :id => 27 } ]

US Meridian Map

The US is divided into several meridians. A larger map and table are available for reference.

US Meridian Table

Each meridian has a corresponding numeric key mapping:

State	Meridian	Code	State	Meridian	Code
AL	Huntsville	16	AL	St. Stephens	25
AL	Tallahasee	29	AR	5th	05
AZ	Gila-Salt River	14	AZ	Navajo	22
AZ	San Bernardino	27	CA	Gila-Salt River	14
CA	Humboldt	15	CA	Mount Diablo	21
CA	San Bernardino	27	CO	6th	06
CO	New Mex	23	CO	Ute	31
FL	Tallahasee	29	IA	5th	05
ID	Boise	08	IL	2nd	02
IL	3rd	03	IL	4th Illinois	04
IN	1st	01	IN	2nd	02
KS	6th	06	LA	Louisiana	18
LA	St. Helena	24	MI	Michigan	19
MN	5th	05	MN	4th	46
MO	5th	05	MS	Chickasaw	09
MS	Choctaw	10	MS	Huntsville	16
MS	St. Stephens	25	MS	Washington	32
MT	Prin	20	ND	5th	05
NE	6th	06	NM	New Mex	23
NV	Mount Diablo	21	NV	San Bernardino	27
OH	1st	01	OH	Michigan	19
OH	Ohio River Survey	35	OH	Between the Miamis	36
OH	Muskingum River Basin	37	OH	Ohio River Basin	38
OH	1st Scioto River Base	39	OH	2nd Scioto River Base	40
OH	3rd Scioto River Base	41	OH	Twelve Mile Square	43
OH	West of Great Miami	47	OH	US Military Survey	48
OH	Ct West Res	91	OH	Ohio CO Pur	92
OH	Va Military Survey	93	OK	Cimarron	11
OK	Indian	17	OR	Willamette	33
SD	5th	05	SD	6th	06
SD	Black Hills	07	UT	Salt Lake	26
UT	Uintah Spec	30	WA	Willamette	33
WI	4th	46	WY	6th	06
WY	Wind River	34