# UNCLASSIFIED

Fields and Controls

This section describes each of the fields and other controls that are contained in the Input Area and/or the Output Area of the GEOTRANS main window. Many of these same fields and controls can also be found in the Input Area and/or the Output Area of the GEOTRANS File Processing window.

90%CE

90%LE

90%SE

British National Grid Coordinate String

Central Meridian

Coordinate Reference Frame

Datum

Easting/X

Ellipsoid

F-16 GRS Coordinate String

False Easting

False Northing

GARS_Coordinate String

GEOREF Coordinate String

Height

Height Type

Hemisphere

Latitude

(1st or 2nd)Latitude

Longitude

(1st or 2nd)Longitude

MGRS Coordinate String

Northing/Y

Orientation

Origin Height

Origin Latitude

Origin Longitude

Override

Scale Factor

Sources

(1st or 2nd)Standard Parallel

USNG Coordinate String

X

Y

Z

Zone

90%CE

The 90% circular error (CE), in meters, estimates the horizontal accuracy of coordinates. Values can be entered directly into this field to indicate the accuracy of the input coordinates. Values can also be entered into this field by selecting a coordinate source from the Sources pull-down menu. When a conversion is performed, this field displays the accuracy of the output coordinates.

90%LE

The 90% linear error (LE), in meters, estimates the vertical accuracy of geodetic heights. Values can be entered directly into this field to indicate the accuracy of the input coordinates. Values can also be entered into this field by selecting a coordinate source from the Sources pull-down menu. When a conversion is performed, this field displays the accuracy of the output coordinates.

90%SE

The 90% spherical error (SE), in meters, estimates the three-dimensional accuracy of geocentric and Local Cartesian coordinates. Values can be entered directly into this field to indicate the accuracy of the input coordinates. Values can also be entered into this field by selecting a coordinate source from the Sources pull-down menu. When a conversion is performed, this field displays the accuracy of the output coordinates.

British National Grid Coordinate String

This field is used to enter or display a British National Grid coordinate string. A British National Grid coordinate string is an alphanumeric string consisting of two letters, followed by a sequence of up to ten digits.

A British Grid is divided into twenty five 500,000 unit squares. Each square is identified by an alphabetic letter. Letters are arranged alphabetically left to right, top to bottom. The letter I is omitted. Each 500,000 unit square is divided into twenty five 100,000 unit squares. Each 100,000 unit square is also identified by a letter. Letters of the 100,000 unit squares are arranged the same as the 500,000 unit squares. The first letter of a British National Grid coordinate string represents the 500,000 unit square and the second letter represents the 100,000 unit square.

The remainder of the British National Grid coordinate string consists of the numeric Easting and Northing values within the 100,000-meter grid square. The left half of the digit sequence is the Easting value, which is read to the right from the left edge of the 100,000-meter grid square. The right half of the digit sequence is the Northing value, which is read northward from the bottom edge of the 100,000-meter grid square. Both the Easting and Northing values are within the range from 0 to 99,999 meters. Both Easting and Northing values must have the same resolution and must include leading zeros. It is desirable to leave a space between the letters and numbers.

Examples:

SJ 1108977917 (1m resolution)

SJ 111779 (100m resolution)

SJ 18 (10,000m resolution)

Central Meridian

This field is used to enter or display the Central Meridian parameter of a map projection. The Central Meridian is the longitude value at the horizontal center of a map projection. This longitude is often also the Origin Longitude of the projected coordinate system. For the Polar Stereographic map projection, the Central Meridian specifies the longitude line that falls along the negative Y axis of the projection. See Longitude for the details of the format of this field.

Coordinate Reference Frame

This pull-down list displays the name of the currently selected input or output coordinate reference frame. It also allows you to change the current input or output coordinate reference frame selection. Click on the arrow to cause the scrolling list of supported coordinate reference frames to appear, scroll up or down until the desired entry is visible, and click on the entry to select it.

This pull-down list also appears in the lower area of the File Processing window, where it displays the currently selected output coordinate reference frame that will be used for file processing, and can be used, as described above, to change that selection.

Datum

This pull-down list displays the code and name of the currently selected input or output datum. It also allows you to change the current input or output datum selection. Click on the arrow to cause the scrolling list of supported datums to appear, scroll up or down until the desired entry is visible, and click on the entry to select it.

This pull-down list also appears in the lower area of the GEOTRANS File Processing window, where it displays the currently selected output datum that will be used for file processing, and can be used, as described above, to change that selection.

Easting/X

This field is used to enter or display a map projection X coordinate, also called an Easting, in meters. The format of map projection coordinates consists of an optional sign (+/-) followed by a sequence of digits, limited only by the size of the field. The display of output Easting/X values may be affected by the setting of the Precision option, which causes the value to be rounded to the specified level of precision (e.g. 100m).

The range of valid Easting/X values varies for different map projections. For UTM, Easting/X values must be between 100,000 and 900,000. For UPS, Easting/X values range from 0 up to 4,000,000. For most other projections, the valid range of Easting/X values is calculated based on the current ellipsoid parameters and the map projection parameter values.

Examples:

500000

-200512

Ellipsoid

This field displays the code and name of the currently selected input or output reference ellipsoid. You cannot select an ellipsoid directly; it is determined by the current input or output datum selection.

This field also appears in the lower area of the GEOTRANS File Processing window, where it displays the code and name of the output reference ellipsoid that will be used for file processing.

F-16 GRS Coordinate String

This field is used to enter or display an F-16 Grid Reference System (GRS) coordinate string. An F-16 GRS coordinate string is a variant of an MGRS coordinate string (see below).

At 100,000m precision, an F-16 GRS coordinate string includes two trailing zeros, following the zone number, the zone letter, and the two-letter 100,000m square designation. In a standard MGRS coordinate string, the presence of these zeros would imply 10,000m precision. However, due to a quirk in the F-16 navigation system, strings of this form are used to designate a 100,000m square. Except for this quirk, F-16 GRS coordinates are identical to MGRS coordinates.

False Easting

This field is used to enter or display a False Easting parameter for a map projection. The False Easting defines the X projection coordinate value, in meters, at the origin of the projection, and is normally used to avoid having to deal with negative coordinate values. The format of a False Easting value consists of an optional sign (+/-) followed by a sequence of digits, limited only by the size of the field.

Examples:

500000 (UTM)

2000000 (UPS)

False Northing

This field is used to enter or display a False Northing parameter for a map projection. The False Northing defines the Y projection coordinate value, in meters, at the origin of the projection, and is normally used to avoid having to deal with negative coordinate values. The format of a False Northing value consists of an optional sign (+/-) followed by a sequence of digits, limited only by the size of the field.

Examples:

10000000 (UTM)

2000000 (UPS)

GARS Coordinate String

This field is used to enter or display a GARS coordinate string. A GARS coordinate string is an alphanumeric string consisting of three digits followed by two letters and two digits. The first three digits identify the 30 minute east/west quadrangle, ranging from 001 to 720. The next two letters identify the 30 minute north/south quadrangle, ranging from AA to QZ, omitting I and O. The next digit identifies a 15 minute cell within that quadrangle. This value ranges from 1 to 4, arranged left to right, top to bottom. The last digit identifies a 5 minute cell within the 15 minute cell. This value ranges from 1 to 9, arranged as a keypad left to right, top to bottom.

Examples:

361HN (30 minute precision)

361HN3 (15 minute precision)

361HN37 (5 minute precision)

GEOREF Coordinate String

This field is used to enter or display a GEOREF coordinate string. A GEOREF coordinate string is an alphanumeric string consisting of two pairs of letters, followed by a sequence of up to ten digits.

The first pair of letters identifies a 15˚ quadrangle. The first letter represents the southwest coordinate in the X direction (longitude). The 24 letters from A to Z (omitting I and O) correspond to the twenty-four GEOREF 15˚ longitude zones. The second letter represents the southwest coordinate in the Y direction (latitude). The 12 letters from A to M (omitting I) correspond to the twelve GEOREF 15˚ latitude zones for a total of 288 15˚ by 15˚ quadrangles globally.

The second pair of letters identifies a specific 1˚ by 1˚ GEOREF cell within the 15˚ by 15˚ quadrangle. The first letter represents the X coordinate (longitude) of the southwest corner of the cell. The 15 letters from A to Q (omitting I and O) correspond to the fifteen 1˚ longitude bands within the quadrangle. The second letter represents the Y coordinate (latitude) of the southwest corner of the cell. The 15 letters from A to Q (omitting I and O) correspond to the fifteen 1˚ latitude bands within the quadrangle. These letters partition each 15˚ by 15˚ GEOREF quadrangle into a total of 225 1˚ by 1˚ cells.

The remainder of the GEOREF coordinate string consists of the numeric longitude and latitude values within the 1˚ by 1˚ cell. The left half of the digit sequence is the longitude value, in decimal minutes, with an implied decimal point after the first two digits. The right half of the digit sequence is the latitude value, in decimal minutes, with an implied decimal point after the first two digits. Thus both the latitude and longitude have a maximum resolution of 0.001 minute (approximately 2 meters). Both the longitude and the latitude value must have the same resolution and must include leading zeros.

Examples:

GJQF4500030000 (0.001 minutes resolution)

GJQF4530 (1 minute resolution)

MKPG12000400 (0.01 minute resolution)

Height

This field is used to enter or display a height, in meters, relative to either the ellipsoid surface (i.e., an ellipsoidal height) or relative to the geoid surface or local mean sea level (i.e., a geoid/MSL height). Positive values are above the surface, while negative values are below the surface. The format of height values consists of an optional sign (+/-) followed by a sequence of digits. The display of ellipsoidal height values may be affected by the setting of the Precision option, which causes the value to be rounded to the specified level of precision (e.g. 10m).

Examples:

100

-1000

Height Type

This pull-down list is used to specify or display the type of height values, if any, used with Geodetic coordinates.

Click on the item labeled “No Height” if only two-dimensional Geodetic coordinates are being used.

Click on the item labeled “Ellipsoid Height” to specify that the input, or desired output, height values are measured relative to the surface of the selected ellipsoid.

Click on the item labeled “MSL-EGM96-15M-BL Height (recommended)” to specify that the input, or desired output, height values are measured relative to the surface of the geoid defined by the Earth Gravity Model 1996 (EGM 96), using a 15-minute grid and bilinear interpolation. This is the recommended model for gravity-related heights, as it is the most accurate. The three following models are included for compatibility with older systems.

Click on the item labeled “MSL-EGM96-VG-NS Height” to specify that the input, or desired output, height values are measured relative to the surface of the geoid defined by the Earth Gravity Model 1996 (EGM 96), using a variable resolution grid and natural spline interpolation.

Click on the item labeled “MSL-EGM84-10D-BL Height” to specify that the input, or desired output, height values are measured relative to the surface of the geoid defined by the Earth Gravity Model 1984 (EGM 84), using a 10-degree grid and bilinear interpolation.

Click on the item labeled “MSL-EGM84-10D-NS Height” to specify that the input, or desired output, height values are measured relative to the surface of the geoid defined by the Earth Gravity Model 1984 (EGM 84), using a 10-degree grid and natural spline interpolation.

Note that the Height Type selection is automatically set to No Height whenever the other currently selected coordinate reference system is two-dimensional. For file processing, the Height Type selection for output Geodetic coordinates is automatically set to No Height whenever the coordinate reference system specified in the input file is two-dimensional.

Hemisphere

This pair of radio buttons is used to specify or display the hemisphere (Northern or Southern) for UPS and UTM projections. Click on the button labeled 'N' to select the Northern hemisphere, or on the button labeled 'S' to select the Southern hemisphere.

Latitude

This field is used to enter or display a geodetic latitude value in decimal degrees, degrees/minutes, or degrees/minutes/seconds.

Latitude limits:

-90˚ to +90˚ (90˚S to 90˚N)

-90˚ at the South Pole

0˚ at the Equator

+90˚ at the North Pole

A latitude field can be entered or displayed in three different formats:

sDD/MM/SS.SSh (degrees/minutes/seconds)

-90 <= DD <= 90

0 <= MM < 60

0 <= SS.SS < 60

sDD/MM.MMMMh (degrees/minutes)

-90 <= DD <= 90

0 <= MM.MMMM < 60

sDD.DDDDDDh

-90 <= DD.DDDDDD <= 90

Where s represents an optional sign (+ or -), and h represents an optional hemisphere (N or S, in either upper or lower case). The sign and hemisphere are mutually exclusive. If neither a sign nor a hemisphere is included, a positive value (Northern hemisphere) for degrees is assumed. Valid separators for the degrees, minutes, and seconds subfields are / (slash), : (colon), or a blank space.

Latitude values may be entered using any of the legal formats, or combinations thereof. The display format of output latitude values is controlled by the Geodetic Format settings in the Options menu. The displayed format of latitude values may also be affected by the setting of the Precision option. For example, if the Units option is set to degrees/minutes/seconds, but the Precision option is set to 1 minute, the output value will be rounded to minutes and the seconds subfield will not be displayed.

Examples:

56/24/32.01 (degrees/minutes/seconds)

56 24 32.01 (degrees minutes seconds)

-34/32/34 (degrees/minutes/seconds)

34:32:34S (degrees:minutes:seconds)

+78/23.438 (degrees/minutes)

-82.8475647 (degrees)

Invalid Examples:

-56/24/32.01S (includes both sign and hemisphere)

120 45 31N (degrees subfield out of valid range)

60 99 59.99S (minutes subfield out of valid range)

5:**:00N (includes invalid characters)

(1st or 2nd) Latitude

These fields are used to enter or display the first and second Latitude parameters of the Oblique Mercator projection. Latitude 1 and Latitude 2 are the latitude values of the first and second points lying on the central line. See Latitude for the details of the format of this field.

Longitude

This field is used to enter or display a geodetic latitude value in decimal degrees, degrees/minutes, or degrees/minutes/seconds.

Longitude limits:

-180˚ to +360˚ (180˚ W to 360˚ E)

0˚ at the Prime meridian

A longitude field can be entered or displayed in three different formats:

sDDD/MM/SS.SSh (degrees/minutes/seconds)

-180 <= DDD <= 360

0 <= MM < 60

0 <= SS.SS < 60

sDDD/MM.MMMMh (degrees/minutes)

-180 <= DDD <= 180

0 <= MM.MMMM < 60

sDDD.DDDDDDh (degrees)

-180 <= DDD.DDDDDD <= 180

Where s represents an optional sign (+ or -), and h represents an optional hemisphere (E or W, in either upper or lower case). The sign and hemisphere are mutually exclusive. If neither a sign nor a hemisphere is included, a positive value (Eastern hemisphere) for degrees is assumed. Valid separators for the degrees, minutes, and seconds subfields are / (slash), : (colon), or a blank space.

Longitude values may be entered using any of the legal formats, or combinations thereof. The display format of output longitude values is controlled by the Geodetic Format settings in the Options menu. The displayed format of longitude values may also be affected by the setting of the Precision option. For example, if the Units option is set to degrees/minutes/seconds, but the Precision option is set to 1 minute, the output value will be rounded to minutes and the seconds subfield will not be displayed.

Examples:

156/24/32.01 (degrees/minutes/seconds)

-34/32/34 (degrees/minutes/seconds)

326 32 34 (degrees minutes seconds)

34:32:34W (degrees:minutes:seconds)

78/23.438 (degrees/minutes)

-82.8475647 (degrees)

Invalid Examples:

-56/24/32.01E (includes both sign and hemisphere)

200 45 31W (degrees subfield out of valid range)

60 99 59.99E (minutes subfield out of valid range)

5:**:00W (includes invalid characters)

(1st or 2nd) Longitude

These fields are used to enter or display the first and second Longitude parameters of the Oblique Mercator projection. Longitude 1 and Longitude 2 are the longitude values of the first and second points lying on the central line. See Longitude for the details of the format of this field.

MGRS Coordinate String

This field is used to enter or display a Military Grid Reference System (MGRS) coordinate string. An MGRS coordinate string is an alphanumeric string consisting of a zone designation, a two-letter 100,000-meter grid square designator, and a sequence of up to ten digits, which provide Easting and Northing coordinates with the grid square with a resolution of up to 1 meter. MGRS coordinates are defined for the primary UTM and UPS areas, but not for the overlap areas.

In the UTM area, the zone designation consists of the two-digit UTM zone number, with any leading zero included, followed by a zone letter that identifies a band of geodetic latitude. Beginning at 80˚ S and proceeding northward, the 20 latitude bands are lettered C through X, omitting I and O. The bands are all 8˚ high except band X (72˚ N to 84˚ N), which is 12˚ high.

In the UPS (polar) areas, the zone designation consists of a single letter, as follows:

A in the Southern and Western Hemispheres,

B in the Southern and Eastern Hemispheres,

Y in the Northern and Western Hemispheres, and

Z in the Northern and Eastern Hemispheres.

The 100,000-meter grid square designator consists of a pair of letters. The letters that identify a particular 100,000-meter square depend on the ellipsoid, the zone, and the location within the zone.

The remainder of the MGRS coordinate string consists of the numeric Easting and Northing values within the 100,000-meter grid square. The left half of the digit sequence is the Easting value, which is read to the right from the left edge of the 100,000-meter grid square. The right half of the digit sequence is the Northing value, which is read northward from the bottom edge of the 100,000-meter grid square. Both the Easting and Northing values are within the range from 0 to 100,000 meters. Both Easting and Northing values must have the same resolution and must include leading zeros.

Examples:

19KFC24782147 (10m resolution)

YXK3526742583 (North polar area, 1m resolution)

17MPT1704763023 (1m resolution)

17MPT1763 (1km resolution)

Northing/Y

This field is used to enter or display a map projection Y coordinate, also called a Northing, in meters. The format of map projection coordinates consists of an optional sign (+/-) followed by a sequence of digits, limited only by the size of the field. The display of output Northing/Y values may be affected by the setting of the Precision option, which causes the value to be rounded to the specified level of precision (e.g. 100m).

The range of valid Northing values varies for different map projections. For UTM, Northing/Y values range from 0 to 10,000,000. For UPS, Northing/Y values range from 0 up to 4,000,000. For most other map projections, the valid range of Northing/Y values is calculated based on the current ellipsoid parameters and the map projection parameter values.

Examples:

5000000

-1234567

Orientation

This field is used to enter or display the Orientation of a Local Cartesian coordinate system. The Orientation is the clockwise rotation angle from north to the positive Y axis of a Local Cartesian coordinate system. See Longitude for the details of the format of this field.

Origin Height

This field is used to enter or display the Origin Height of a Local Cartesian coordinate system. The Origin Height specifies the vertical portion of the location of the origin of a Local Cartesian coordinate system. It specifies the vertical location of the origin relative to the surface of the reference ellipsoid. See Height for the details of the format of this field.

Origin Latitude

This field is used to enter or display the Origin Latitude parameter of a particular projection, or the Origin Latitude of a Local Cartesian coordinate system. The Origin Latitude is the latitude value at the vertical center of a projection, or specifies the latitude portion of the location of the origin of a Local Cartesian coordinate system. See Latitude for the details of the format of this field.

Origin Longitude

This field is used to enter or display the Origin Longitude of a Local Cartesian coordinate system. The Origin Longitude specifies the longitude portion of the location of the origin of a Local Cartesian coordinate system. See Longitude for the details of the format of this field.

Override

This control consists of a single radio button, plus a field in which an overriding UTM zone can be specified (see Zone below). When the button is selected, the field must be filled in with a UTM zone value. UTM output coordinates will then be interpreted in terms of this zone, rather than their ‘natural’ zone. The override zone must be adjacent to the natural zone, and the coordinates converted must be located within the overlap area of the override zone and the natural zone.

Scale Factor

This field is used to enter or display the projection scale factor for a map projection. The scale factor is the multiplier that reduces a distance in a map projection to the actual distance on the chosen reference ellipsoid. The values of this field are positive real numbers ranging from 0.3 to 3.0, with up to five decimal places.

Examples:

1.00000

0.9996

0.9994

Sources

This pull-down list displays the names of possible sources for input sources. These include GPS coordinates, various types of hardcopy maps, and various types of digital geospatial data. Selecting one of these entries causes all three of the standard error fields (90%CE, 90%LE, and 90%SE) to be set to values appropriate for the selected source.

(1stor 2nd) Standard Parallel

These fields are used to enter or display one of the Standard Parallel parameters of an Albers Equal Area Conic, Equidistant Cylindrical, Lambert Conformal Conic, Mercator, or Polar Stereographic map projection. A Standard Parallel is a latitude value where the projection surface intersects the surface of the reference ellipsoid, and the point scale factor is one. See Latitude for the details of the format of this field.

USNG Coordinate String

This field is used to enter or display a United States National Grid (USNG) coordinate string. A USNG coordinate string is an alphanumeric string consisting of a zone designation, a two-letter 100,000-meter grid square designator, and a sequence of up to ten digits, which provide Easting and Northing coordinates with the grid square with a resolution of up to 1 meter. USNG coordinates are defined for the primary UTM and UPS areas, but not for the overlap areas.

In the UTM area, the zone designation consists of the two-digit UTM zone number, with any leading zero included, followed by a zone letter that identifies a band of geodetic latitude. Beginning at 80˚ S and proceeding northward, the 20 latitude bands are lettered C through X, omitting I and O. The bands are all 8˚ high except band X (72˚ N to 84˚ N), which is 12˚ high.

In the UPS (polar) areas, the zone designation consists of a single letter, as follows:

A in the Southern and Western Hemispheres,

B in the Southern and Eastern Hemispheres,

Y in the Northern and Western Hemispheres, and

Z in the Northern and Eastern Hemispheres.

The 100,000-meter grid square designator consists of a pair of letters. The letters that identify a particular 100,000-meter square depend on the ellipsoid, the zone, and the location within the zone.

The remainder of the USNG coordinate string consists of the numeric Easting and Northing values within the 100,000-meter grid square. The left half of the digit sequence is the Easting value, which is read to the right from the left edge of the 100,000-meter grid square. The right half of the digit sequence is the Northing value, which is read northward from the bottom edge of the 100,000-meter grid square. Both the Easting and Northing values are within the range from 0 to 100,000 meters. Both Easting and Northing values must have the same resolution and must include leading zeros.

Examples:

19KFC24782147 (10m resolution)

YXK3526742583 (North polar area, 1m resolution)

17MPT1704763023 (1m resolution)

17MPT1763 (1km resolution)

X

This field is used to enter or display a geocentric or Local Cartesian X coordinate, in meters. The format of geocentric coordinates consists of an option sign (+/-) followed by a sequence of digits, limited only by the size of the field. The display of geocentric coordinate values may be affected by the setting of the Precision option, which causes the value to be rounded to the specified level of precision (e.g. 100m).

Examples:

6378137

-1234567

Y

This field is used to enter or display a geocentric or Local Cartesian Y coordinate, in meters. The format of geocentric coordinates consists of an option sign (+/-) followed by a sequence of digits, limited only by the size of the field. The display of geocentric coordinate values may be affected by the setting of the Precision option, which causes the value to be rounded to the specified level of precision (e.g. 100m).

Examples:

6378137

-1234567

Z

This field is used to enter or display a geocentric or Local Cartesian Z coordinate in meters. The format of geocentric coordinates consists of an option sign (+/-) followed by a sequence of digits, limited only by the size of the field. The display of geocentric coordinate values may be affected by the setting of the Precision option, which causes the value to be rounded to the specified level of precision (e.g. 100m).

Examples:

6378137

+500

Zone

This field is used to enter or display a UTM zone number. A UTM zone number identifies one of sixty 6° -wide longitudinal zones. Zones are numbered sequentially from west to east. Zone 1 is located between 180° W and 174° W. UTM zone numbers must be in the range from 1 to 60.

# UNCLASSIFIED