| Name | Range | Description | Optional? |
|---|---|---|---|
| COORDINATE_SYSTEM_DEF | any string | This parameter is used to specify 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. | This parameter specifies the datum to be used for the projection. Either a datum or an ellipsoid must be specified for each coordinate system. | Yes |
| DESC_NM | any string | This parameter specifies a descriptive name of the definition. | Yes |
| EL_NAME | See Ellipsoids. |
This parameter specifies the ellipsoid 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 will be applied. |
Yes |
| GROUP | Used to classify coordinate systems into groups to make selection of a coordinate system from the 1,000+ provided a bit easier. | Yes | |
| MAX_LNG | This parameter is optional and can be used to specify 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 | This parameter is optional and can be used to specify 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 | This parameter is optional and can be used to specify 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 | This parameter is optional and can be used to specify 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 | This parameter is optional and can be used to specify 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 | This parameter is optional and can be used to specify 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 | This parameter is optional and can be used to specify 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 | This parameter is optional and can be used to specify 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 | Used to specify 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 | Used to specify 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. | These parameters specify the value of as many as 24 parameters which are specific to the particular projection in use. The use of these items varies from one projection to another. | No |
| PROJ | See Projection Types. | This parameter specifies 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 linked to this table. | No |
| QUAD | -4..4 | This parameter specifies the quadrant of the Cartesian coordinates produced by the coordinate system. See Quadrant. | Yes |
| SCL_RED | Used to specify the scale reduction which 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, e.g. 0.9996, or as a ratio, e.g. 1:2500. A value of 1.0 or greater is unusual, but is accepted. | Yes | |
| SOURCE | any string | This parameter specifies the person or agency supplying the definition. | Yes |
| UNIT | See Coordinate Units Supported. | This parameter specifies the name of the units used to measure coordinates in the coordinate system. | No |
| X_OFF | Used to specify 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 | Used to specify 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 | Used to specify 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 | Used to specify 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 |