before the decimal point. The first two digits
(1,100,000 meters) can be separated from the next five
by a space. The number of digits following the
decimal point are dependent upon the order of survey
and the accuracies needed. An example of a UPS grid
coordinate is 17 81256.41 - 26 41416.82.
3-18 UTM/UPS Overlap
a. General. As with the Transverse Mercator and
Polar Stereographic Projections, the UTM and UPS
systems provide for a one degree overlap; each system
continuing into the other for 30 minutes.
b. UTM/UPS. The standard limits of the UTM and
UPS grid systems are at 84° N and 80° S latitude. A
30 minute overlap extends the UTM to 84° 30' N and
80° 30' S latitude. The UPS is extended 30 minutes to
83° 30' N and 79° 30' S latitude.
3-19 Gauss-Kruger Grid
a. The Gauss-Kruger (GK) Grid System is
referenced to the Gauss-Kruger (Transverse Mercator -
tangent) projection. The GK grid can be considered a
universal grid, like UTM and UPS; however, it is
generally thought of as a local grid covering Europe,
the Middle East, Asia, and parts of Africa. The grid is
usually placed on a projection using one of the
following reference ellipsoids:
Krassovsky:
Russia (all former USSR),
Albania after 1945, Afghanistan,
Bulgaria,
China to 1981,
Czechoslovakia, Germany,
Hungary, Laos, Poland, Romania, and
Somalia
GRS (China) 1980:
China after 1981
Bessel:
Albania through 1945,
Austria, Germany, and North Korea
b. The GK grid has many similarities to the UTM
grid.
1. Each GK grid zone is 6° wide and they are
numbered from 1 to 60; however, the zones start at the
Prime Meridian (0° longitude) instead of the
International Dateline (180° longitude). This
difference offsets the grid zone numbers by 30;
therefore, UTM grid zone 6 is the same as GK grid
zone 36.
2. The central meridian of each GK grid zone is the
same as the central meridian of each UTM grid zone.
3. The north and south limits of the GK grid have
not been rigidly defined but it is generally accepted
that the limits are similar to those of the UTM grid
system.
4. Grid convergence is the same for a GK grid
coordinate as it is for the corresponding UTM
coordinate.
c. The origin for coordinates is the same in the GK
system as the UTM system. The false value applied to
the equator is the same in both systems. The easting;
however, is slightly different. The false value applied
to the central meridian is 500,000, like UTM, with the
grid zone number added to the millions place. For
example, the easting value of the central meridian in
GK grid zone 6 is 6,500,000 meters.
d. GK Grid Coordinates. A GK grid coordinate is
expressed with the northing written before the easting.
The northing is written with seven digits before the
decimal point with and may have a space between the
first two and the next five digits. The easting is
written with the grid zone first, then with six digits
before the decimal point. A space can be placed
between the 100,000 meter place and the next five
digits. An example of a GK grid coordinate in zone 5
is: 38 25411.24 - 56 39127.84. (This example uses
the same numbers as the example for a UTM
coordinate, para 3-13,f,1.)
3-20 Converting from GK to UTM
a. General. Conversions from the GK grid to the
UTM grid can be performed simply by applying the
UTM scale factor to the GK grid. The UTM and GK
grids are both referenced to the same projection (the
Transverse Mercator Projection and Gauss-Kruger
Projection can be considered the same, para 7a), the
only difference being that the UTM grid is oriented to
a secant cylinder while the GK grid is oriented to a
tangent cylinder. Since both grid systems use the same
central meridians in each zone and since the false
values applied to the origins for easting and northing
are basically the same, the only major difference to be
considered is the scale factor. The Gauss-Kruger
Projection has a scale factor of 1.00 (exact or unity) at
DRAFT
3-20