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Coordinate Specifications for Spatial Data Exchange Between Minnesota State Agencies

Date Issued: Approved by the Minnesota Governor's Council on Geographic Information June 9, 1998

Applicability:
Who cares about these standards?
All developers, distributors, and users of existing or planned spatial databases that originate or are maintained within State of Minnesota government agencies. Spatial databases are those that include explicit references to the geographic location of the features they describe.

When do they apply? When do they not apply?
This standard has been developed to facilitate exchange of data between Minnesota government agencies. Use of this standard is mandatory when the following two conditions exist:

  • a state agency is transferring data to another state agency, AND
  • no commonly agreed to internal coordinate encoding exchange standard exists between the two agencies.

Use of this standard is recommended when Minnesota state government agencies are publishing data for use by external stakeholders (including other units of government operating at other levels). This standard applies to data that are being transferred, and does not restrict the manner in which data are stored internally, although the capability to translate data into a form consistent with this standard should exist within all affected agencies.

Purpose of these Standards:
The purpose of this standard is to define a common framework for spatial data exchange. This benefits all consumers of state-produced data by eliminating the need to prepare customized procedures for processing coordinate information. Deploying the standard allows for the streamlining of exchange procedures between data producers and consumers, thereby reducing costs associated with data processing and handling.

Standard Requirements:
This standard defines expression of coordinate values as follows:

Projection: Universal Transverse Mercator (an instance of the Transverse Mercator Projection as defined by Snyder, 1987).

UTM Zone: 15 (extended to cover the entire land surface of the State of Minnesota)

Units: meters

Spheroid: GRS1980

Datum: North American Datum of 1983 (NAD83)

Recognizing that some coordinate processing software products may not directly support UTM as an independent projection, the following manual projection parameters for the standard are provided:

Projection name: Transverse Mercator

Scale factor at central meridian: 0.9996

Longitude of central meridian: 93 00 00 degrees

Latitude of origin: 00 00 00 degrees

False easting (meters): 500,000

False northing (meters): 0

Units: meters

Spheroid: GRS1980

Datum: North American Datum of 1983 (NAD83)

Compliance:
What constitutes compliance?
Minnesota state agencies must be capable of translating coordinate information into a form consistent with the standard. Agencies may administer or apply data in alternative forms. Agencies may also distribute or publish data in alternative forms as long as they are made available in the standard form as an option.

How will compliance be measured?
Evidence of compliance will be determined based on reports of satisfactory data transfers between state agencies, and the development of distribution strategies that incorporate the standard.

Notes:

The coordinate specification provided here does not differentiate between adjustments to the geodetic network (for example, it includes no specific reference to the 1996 High Accuracy Reference Network (HARN) adjustment). The 1996 HARN adjustment, which is not yet widely supported in the spatial data processing industry, resulted in a positional shift that averaged 1/3 meter within Minnesota. This spatial data exchange specification may be amended at some later date to reflect the adoption of an industry standard for these types of adjustments. Until that time, the adjustment specification used in encoding the coordinates within any given transfer data set should be noted in the accompanying metadata.

References and Sources of More Information:

National Imagery and Mapping Agency, Technical Manual 8358.1 Datums, Ellipsoids, Grids, and Grid Reference Systems, 1990.

Snyder, J. P. Map Projections--A Working Manual. U. S. Geological Survey Professional Paper 1395. Washington, DC: U. S. Government Printing Office, pp. 38-75, 1987.

The Universal Transverse Mercator (UTM) Grid USGS Fact Sheet 077-01 (August 2001)
http://erg.usgs.gov/isb/pubs/factsheets/fs07701.html

Further information about this standard may be obtained from Office of Geographic and Demographic Analysis phone: 651.201.2481