Local Coordinate Systems

Name	Range	Description	Optional?
COORDINATE_SYSTEM_DEF	any string	The name of the coordinate system being defined. May be used to identify the coordinate system of a reader or writer, or as an argument to @Reproject or _COORDINATE_SYSTEM.	No
DT_NAME	See Datums.	The datum key to be used for the projection. Either a datum or an ellipsoid must be specified for each coordinate system. When features tagged with this type of coordinate system are reprojected, no datum transformation is applied.	Yes, unless EL_NAME is specified
DESC_NM	any string, 63 characters maximum	A descriptive name of the coordinate system.	Yes
EL_NAME	See Ellipsoids.	The ellipsoid key name for a cartographically referenced coordinate system. A coordinate system is cartographically referenced to the ellipsoid named by this specification if, and only if, the datum key name specification is omitted. If both DT_NAME and EL_NAME specifications are provided, the EL_NAME specification is ignored. When features tagged with this type of coordinate system are reprojected, no datum transformation is applied.	Yes, unless DT_NAME is specified
GROUP		Used to classify coordinate systems into groups to simplify selection of a coordinate system from the 1,000+ provided.	Yes
MAX_LNG		The maximum longitude of the useful range of the coordinate system. The value is given in degrees relative to Greenwich. Positive values indicate east longitude, while negative values indicate west longitude. Its value should be normalized between -360 and +360 and, when used, must be algebraically greater than the MIN_LNG parameter.	Yes
MIN_LNG		The minimum longitude of the useful range of the coordinate system. The value is given in degrees relative to Greenwich. Positive values indicate east longitude, while negative values indicate west longitude. Its value should be normalized between -360 and +360 and, when used, must be algebraically less than the MAX_LNG parameter.	Yes
MAX_LAT		The maximum latitude of the useful range of the coordinate system. The value is given in degrees relative to the equator. Positive values indicate north latitude while negative values indicate south latitude. Its value should be normalized between -90 and +90 and when used must be algebraically greater than the MIN_LAT parameter.	Yes
MIN_LAT		The minimum latitude of the useful range of the coordinate system. The value is given in degrees relative to the equator. Positive values indicate north latitude while negative values indicate south latitude. Its value should be normalized between -90 and +90 and, when used, must be algebraically less than the MAX_LAT parameter.	Yes
MAX_XX		The maximum X coordinate value of the useful range of the coordinate system. The value is given in system units. Its value must be algebraically greater than the MIN_XX parameter.	Yes
MIN_XX		The minimum X coordinate value of the useful range of the coordinate system. The value is given in system units. Its value must be algebraically less than the MAX_XX parameter.	Yes
MAX_YY		The maximum Y coordinate value of the useful range of the coordinate system. The value is given in system units. Its value must be algebraically greater than the MIN_YY parameter.	Yes
MIN_YY		The minimum Y coordinate value of the useful range of the coordinate system. The value is given in system units. Its value must be algebraically less than the MAX_YY parameter.	Yes
ORG_LAT		The origin latitude of the coordinate system. This value is specified in degrees relative to the equator. Use positive numbers for north latitude, negative numbers for south latitude.	Yes
ORG_LNG		The origin longitude of the coordinate system. This value is specified in degrees and is always relative to the Greenwich prime meridian. Use positive numbers for east longitude, negative numbers for west longitude.	Yes
PARM1 thru PARM24	Depends on the projection system – see Projection Types.	The value of up to 24 parameters that are specific to the particular projection in use. The use of these items varies from one projection to another. The value is always a real number. Where a longitude is specified, it must be given in degrees, relative to Greenwich, where west longitude and south latitude are negative. Where a latitude is expected, it must be given in degrees relative to the equator where north latitude is positive and south latitude is negative. When an azimuth is specified, it must be given in degrees east of north (that is, west of north would be negative).	No
PROJ	See Projection Types.	The type of map projection used for this definition. This name must come from the Projection Types table and it determines which other parameters may be specified. The parameters used by each projection type are linked to the Projection Types table.	No
QUAD	-4..4	The quadrant of the Cartesian coordinates produced by the coordinate system. See Quadrant. Zero or 1 indicates the normal right-handed Cartesian system where X increases to the east, and Y increases to the north. Quadrants are numbered counterclockwise; therefore, a value of 2 specifies a Cartesian system where X increases to the west, while Y increases north. A value of 3 indicates that X increases to the west and Y increases to the south. A value of 4 indicates that X increases to the east and Y increases to the south. A negative value causes the axes to be swapped after the appropriate quadrant is applied. A value of 1 is assumed if this specification is absent.	Yes
SCL_RED		The scale reduction that may apply to a coordinate system. This value is ignored by the many projections which do not support this feature. The value may be specified as a decimal number (for example, 0.9996), or as a ratio (for example, 1:2500). A value of 1.0 or greater is unusual, but is accepted.	Yes
SOURCE	any string, 63 characters maximum	The person or agency supplying the definition.	Yes
UNIT	See Coordinate Units Supported.	The name of the units used to measure coordinates in the coordinate system.	No
X_OFF		The value of the false easting of the coordinate system. A value of 0.0 is assumed if no specification is made.	Yes
Y_OFF		The value of the false northing of the coordinate system. A value of 0.0 is assumed if no specification is made.	Yes
ZERO_X	any non-negative number	The minimum X value which is to be considered non-zero. X coordinate values whose absolute value is less than the value specified here will be converted to hard zeros. This is used to suppress coordinate output such as 4.3472E-07 which can be of value in certain applications. A value of 0.0 is assumed if no specification is made.	Yes
ZERO_Y	any non-negative number	The minimum Y value which is to be considered non-zero. Y coordinate values whose absolute value is less than the value specified here will be converted to hard zeros. This is used to suppress coordinate output such as 4.3472E-07 which can be of value in certain applications. A value of 0.0 is assumed if no specification is made.	Yes

COORDINATE_SYSTEM_DEF

any string

The name of the coordinate system being defined. May be used to identify the coordinate system of a reader or writer, or as an argument to @Reproject or _COORDINATE_SYSTEM.

No

DT_NAME

See Datums.

The datum key to be used for the projection. Either a datum or an ellipsoid must be specified for each coordinate system.

When features tagged with this type of coordinate system are reprojected, no datum transformation is applied.

Yes, unless EL_NAME is specified

DESC_NM

any string, 63 characters maximum

A descriptive name of the coordinate system.

Yes

EL_NAME

See Ellipsoids.

The ellipsoid key name for a cartographically referenced coordinate system. A coordinate system is cartographically referenced to the ellipsoid named by this specification if, and only if, the datum key name specification is omitted. If both DT_NAME and EL_NAME specifications are provided, the EL_NAME specification is ignored.

When features tagged with this type of coordinate system are reprojected, no datum transformation is applied.

Yes, unless DT_NAME is specified

GROUP

Used to classify coordinate systems into groups to simplify selection of a coordinate system from the 1,000+ provided.

Yes

MAX_LNG

The maximum longitude of the useful range of the coordinate system. The value is given in degrees relative to Greenwich. Positive values indicate east longitude, while negative values indicate west longitude. Its value should be normalized between -360 and +360 and, when used, must be algebraically greater than the MIN_LNG parameter.

Yes

MIN_LNG

The minimum longitude of the useful range of the coordinate system. The value is given in degrees relative to Greenwich. Positive values indicate east longitude, while negative values indicate west longitude. Its value should be normalized between -360 and +360 and, when used, must be algebraically less than the MAX_LNG parameter.

Yes

MAX_LAT

The maximum latitude of the useful range of the coordinate system. The value is given in degrees relative to the equator. Positive values indicate north latitude while negative values indicate south latitude. Its value should be normalized between -90 and +90 and when used must be algebraically greater than the MIN_LAT parameter.

Yes

MIN_LAT

The minimum latitude of the useful range of the coordinate system. The value is given in degrees relative to the equator. Positive values indicate north latitude while negative values indicate south latitude. Its value should be normalized between -90 and +90 and, when used, must be algebraically less than the MAX_LAT parameter.

Yes

MAX_XX

The maximum X coordinate value of the useful range of the coordinate system. The value is given in system units. Its value must be algebraically greater than the MIN_XX parameter.

Yes

MIN_XX

The minimum X coordinate value of the useful range of the coordinate system. The value is given in system units. Its value must be algebraically less than the MAX_XX parameter.

Yes

MAX_YY

The maximum Y coordinate value of the useful range of the coordinate system. The value is given in system units. Its value must be algebraically greater than the MIN_YY parameter.

Yes

MIN_YY

The minimum Y coordinate value of the useful range of the coordinate system. The value is given in system units. Its value must be algebraically less than the MAX_YY parameter.

Yes

ORG_LAT

The origin latitude of the coordinate system. This value is specified in degrees relative to the equator. Use positive numbers for north latitude, negative numbers for south latitude.

Yes

ORG_LNG

The origin longitude of the coordinate system. This value is specified in degrees and is always relative to the Greenwich prime meridian. Use positive numbers for east longitude, negative numbers for west longitude.

Yes

PARM1 thru PARM24

Depends on the projection system – see Projection Types.

The value of up to 24 parameters that are specific to the particular projection in use. The use of these items varies from one projection to another. The value is always a real number. Where a longitude is specified, it must be given in degrees, relative to Greenwich, where west longitude and south latitude are negative. Where a latitude is expected, it must be given in degrees relative to the equator where north latitude is positive and south latitude is negative. When an azimuth is specified, it must be given in degrees east of north (that is, west of north would be negative).

No

PROJ

See Projection Types.

The type of map projection used for this definition. This name must come from the Projection Types table and it determines which other parameters may be specified. The parameters used by each projection type are linked to the Projection Types table.

No

QUAD

-4..4

The quadrant of the Cartesian coordinates produced by the coordinate system. See Quadrant. Zero or 1 indicates the normal right-handed Cartesian system where X increases to the east, and Y increases to the north. Quadrants are numbered counterclockwise; therefore, a value of 2 specifies a Cartesian system where X increases to the west, while Y increases north. A value of 3 indicates that X increases to the west and Y increases to the south. A value of 4 indicates that X increases to the east and Y increases to the south. A negative value causes the axes to be swapped after the appropriate quadrant is applied. A value of 1 is assumed if this specification is absent.

Yes

SCL_RED

The scale reduction that may apply to a coordinate system. This value is ignored by the many projections which do not support this feature. The value may be specified as a decimal number (for example, 0.9996), or as a ratio (for example, 1:2500). A value of 1.0 or greater is unusual, but is accepted.

Yes

SOURCE

any string, 63 characters maximum

The person or agency supplying the definition.

Yes

UNIT

See Coordinate Units Supported.

The name of the units used to measure coordinates in the coordinate system.

No

X_OFF

The value of the false easting of the coordinate system. A value of 0.0 is assumed if no specification is made.

Yes

Y_OFF

The value of the false northing of the coordinate system. A value of 0.0 is assumed if no specification is made.

Yes

ZERO_X

any non-negative number

The minimum X value which is to be considered non-zero. X coordinate values whose absolute value is less than the value specified here will be converted to hard zeros. This is used to suppress coordinate output such as 4.3472E-07 which can be of value in certain applications. A value of 0.0 is assumed if no specification is made.

Yes

ZERO_Y

any non-negative number

The minimum Y value which is to be considered non-zero. Y coordinate values whose absolute value is less than the value specified here will be converted to hard zeros. This is used to suppress coordinate output such as 4.3472E-07 which can be of value in certain applications. A value of 0.0 is assumed if no specification is made.

Yes

Coordinate System Parameters