GRATIC

Description

Generates a graticule (that is, a LONG/LAT grid) transformed to a specified projection. The output graticule is saved in a new vector segment.

Parameters

Name	Type	Length	Value range
Input: Input image layer *	Raster port	1 -
Output: Output grid vector layer	Vector port	0 -
Gratic Increment	String	0 - 1
Map Resolution	Float	0 - 2
Vector Type	String	0 - 1	LINE | POINT Default: LINE
Vector Layer Name	String	0 - 1	Default: gratic
Vector Layer Description	String	0 -

* Required parameter

Parameter descriptions

Input: Input image layer

Specifies the input layer that contains the georeferenced image.

Output: Output grid vector layer

Specifies the output layer that will receive the new vector segment (type VEC:116) to hold the graticule vectors.

Gratic Increment

Specifies the increment for the graticule.

Map Resolution

Specifies the spacing distance between vertices when VTYPE (Vector Type) is specified as LINE. This value is expressed in the georeferenced units (XSize, YSize).

If this parameter is not specified, and VTYPE is specified as LINE, the spacing between the vertices in each LINE will be the largest of the following: 1000 meters, the pixel width, or the pixel height.

If VTYPE is specified as POINT, this parameter is not used; the spacing between the points is controlled by the GINC (Gratic Increment) parameter.

Vector Type

Specifies the type of vector data to generate.

Vector Layer Name

Optionally specifies a name (up to 8 characters) for the output vector segment.

Vector Layer Description

Optionally describes (in up to 64 characters) the contents or origins of the output vector segment.

Details

GRATIC is used to generate a LONG/LAT grid that has been transformed to overlay a specified projection. The output grid is saved as lines or points in a newly created vector segment.

The input file (FILE) specifies the image file in which to store the output vector segment.

If the Vector Type (VTYPE) is specified as LINE, the MAPRES (Map Resolution) parameter defines the distance between the vertices in each line in georeference units. If VTYPE is specifies as POINT, MAPRES will have no effect.

The projection information is defined in a georeference segment 1.

The segment name (DBSN) and description (DBSD) may be specified or defaulted.

The specified or default graticule bounds are stored in the output vector segment's history.

You may need to clip the output vector segment using VECSEL to fit the image georeference bounds, depending on the end requirement for the graticule vectors.