# Coordinates: Definitions and Overview

To change your coordinate preferences, open the File menu and choose Preferences, Coordinate Display. You can specify a Primary coordinate display and an (optional) Alternate Coordinate Display.

**Degrees Minutes Seconds (Dº M' S"):**

This is the default coordinate system in Terrain Navigator Pro and is the most commonly used. This Latitude / Longitude Coordinate system displays the location in Degrees, Minutes, and Seconds. For example, in Deg. Min. Sec. the location of MyTopo's main office would look like this:

45º 46' 50.42" N 108º 30' 14.69" W

**Degrees Minutes (Dº M.M'):**

Like Deg. Min. Sec., this shows the location in terms of Latitude / Longitude,

except that the seconds are replaced by fractional digits (to the right of the decimal point).

*MyTopo's Main Office Location:*

45º 46.8404' N 108º 30.2449' W

**Degrees (D.Dº):**

Also known as Decimal Degrees, this coordinate system represents the

location as one, long decimal number. The digits to the left of the decimal point

indicate the degree, the digits to the right indicate the minutes and seconds.

*MyTopo's Main Office Location:*

45.7806741º N 108.5040825º W

**Universal Transverse Mercator (UTM):**

Often used in the military and in conjunction with GPS units, the UTM coordinate system is completely different from Latitude / Longitude. UTM uses an imaginary grid of equidistant, perpendicular lines, to divide the globe into 60 zones. Position is indicated in meters within a zone. This makes UTM the preferred system for ground navigation.

*MyTopo's Main Office Location:*

12 06

**94**025 E 50

**72**709 N

**Military Grid Reference System (MGRS):**

A system which uses a standard-scaled grid square, based on a point of origin on a map projection of the Earth's surface in an accurate and consistent manner to permit either position referencing or the computation of direction and distance between grid positions.

Terrain Navigator Pro allows you to specify 1 meter, 10 meter, 100 meter, and 1 kilometer MGRS grid intervals. Grid positions are calculated based on the MGRS-3 specification.

*MyTopo's Main Office Location:*

12TXR9402572709 (1 Meter Grid)

**United States National Grid (USNG):**

The USNG system is basically identical to MGRS. The exception being that MGRS and USNG use a different notation when the NAD27 datum is specified. Terrain Navigator Pro allows you to specify 1 meter, 10 meter, 100 meter, and 1 kilometer USNG grid intervals.

*MyTopo's Main Office Location:*

12TXR9402572709 (1 Meter Grid)

**State Plane Coordinate System:**

Coordinate systems established by the U.S. Coast and Geodetic Survey (now the National Ocean Survey), usually one for each State, for use in defining positions of points in terms of plane (x,y) rectangular coordinates. These coordinates may be given in feet or meters.

*MyTopo's Main Office Location:*

559718 ft. N., 2222501 ft. E. (measurement in feet)

170602 m. N., 677419 m. E. (measurement in meters)

**Township/Range System (TRS):**

Uses a rectangular grid system based on a principal meridian and a base line and divided into townships, sections and parcels. This is also known as PLSS (Public Land Survey System.)

*MyTopo's Main Office Location:*

NW NE Sec 03 T001S R026E (Parcel)