UTM Location 2D

Class Name: UTM Location 2D

Superclass - Location 2D

Definition

A coordinate within the Universal Transverse Mercator (UTM) 2D Spatial Reference Frame (SRF).

The Universal Transverse Mercator projection-based Spatial Reference Frame is a cylindrical, conformal projection normally placed tangent to a meridian of the Object Reference Model/Earth Reference Model (ORM/ERM). When secant, two rather than a single meridian are defined; alternatively this can be expressed as a "central scale factor" at the meridian.

Only the ORM/ERM central meridian and equator are straight lines in the Universal Transverse Mercator 2D SRF.

When used to define a 2D coordinate system, the resulting X and Y axes are measured in meters (rather than arc degrees), and a local origin offset is provided. The X axis parallels the equator, increasing in the easterly direction; the Y axis lies along the central meridian, increasing in a northerly direction, and forms a 2D right-handed coordinate system. The origin is defined by the intersection of the parametric central meridian and a parametric parallel.

The UTM SRF extends the TM SRF by specifying the meridian of the positive Y axis, the parallel of the origin, and the central scale factor.

The central meridian is defined in terms of a "zone" ranging from 1 through 60, where the central meridian of Zone 1 is 177 degrees west, and successive Zones occur in 6 degree increments.
The parallel of the origin is fixed at the equator.
The central scale factor is 0.9996, thus "lowering" the plane of the projection to intersect the ORM/ERM at two meridians of secancy (roughly 180,000 meters east and west of the central meridian) where the scale is 1.0. The scale increases to about 1.0010 near the zone boundaries at the equator

In addition, the UTM SRF divides the range of the Y axis into two halves according to the hemispheres. The Y axis origin is located at the equator, however in the northern hemisphere the value of Y at the origin is 0 and in the southern hemisphere the value of Y at the origin is 10,000,000. Furthermore, the origin is defined as having an X coordinate value of 500,000 meters in both hemispheres. This allows all coordinates within a zone to have positive values of both X and Y.

UTM SRF coordinates may thus be related to TM SRF coordinates under the equivalent parametric conditions by the following formulas:

X(UTM) = X(TM) + 500,000
Y(UTM) = Y(TM: Northern Hemisphere) or
= Y(TM: Southern Hemisphere) + 10,000,000

The UTM SRF is only defined between the 84 degree north and 80 degree south parallels.

The canonical 2D Local Tangent Plane (LTP2) SRF, when embedded in a UTM SRF, would have its X and Y axes aligned with the corresponding X and Y axes of the UTM SRF.

See the SEDRIS Spatial Reference Model (SRM) for additional details.