GRATGRID

Description

GRATGRID creates a vector layer representing either a graticule or a grid. The vector layer can be geocoded even though it represents a graticule. The grid or graticule is created based on image extents and increments in the X and Y directions.

Parameters

Name	Type	Length	Value range
Input: Input vector segment or layer	Vector port	0 - 1
InputRaster: Input raster layer	Raster port	0 - 1
Output: Output vector layer *	Vector port	1 - 1
Vector Layer Name	String	0 - 1
Vector Layer Description	String	0 - 1
Layer Type	String	0 - 1	Lines | Points | Polygons Default: Lines
Grid Type	String	0 - 1	Geocoded | Geographic Default: Geocoded
Projection and Extents	geoEdit	- 1024	Any supported projection Default: Pixel
X Increment *	Float	1 - 1	1.0 -
Y Increment *	Float	1 - 1	1.0 -
Report	String	0 - 192	See parameter description

* Required parameter

Parameter descriptions

Input: Input vector segment or layer

Specifies the vector segment from which georeferencing information (projection, bounds) will be taken.

Selecting a new vector layer updates the projection information on the parameters tab.

InputRaster: Input raster layer

Specifies the input raster image.

Selecting a new raster layer updates the projection information on the parameters tab.

Output: Output vector layer

Specifies the output layer to receive the output graticule/grid.

Vector Layer Name

Specifies a name (up to 8 characters) for the output vector layer.

Vector Layer Description

Describes (in up to 64 characters) the contents or origins of the output vector layer.

Layer Type

Specifies the layer type of the output grid/graticule layer.

Grid Type

Specifies the grid type for the output vector layer.

Projection and Extents

Specifies the output projection and extents. This parameter is initially populated based on the projection information of the vector or raster layer if they are selected on the Input tab. If you have both raster and vector input, the raster information takes precedence.

This parameter contains several sections, described below.

Projection

This is a standard projection setup consisting of the projection selection drop-down list, the Earth Model button, a georeferencing string text box, and the More button. Together, these elements define the output projection.

For information about all the projections available, see "Projections and earth models" in the Technical Reference section of the CATALYST Professional help.

Bounds

Sets the coordinate type for the Upper Left/Lower Right coordinates.

Extents

Extents are defined by the Upper Left and Lower Right coordinates. The extents can be entered in either geocoded (X,Y) or geographic (Long/Lat) units, as specified by Bounds; for example, UTM (or most projections) would be Eastings and Northings in meters.

Long/Lat coordinates may be specified in Degrees, Minutes, Seconds (for example, 152d30'00.00" W), or in decimal degrees (for example, -152.5).

X Increment

Specifies the horizontal increment of the graticule or grid. The default value is 1.0.

Y Increment

Specifies the vertical increment of the graticule or grid. The default value is 1.0.

Report

Specifies where to direct the generated report.

Available options are:

• LOG: generates a report on the terminal (default)
• <modulename.RPT>: appends a report to the module's RPT file
• DISK: generates a report on file "IMPRPT.LST"

Details

GRATGRID creates a vector layer representing either a graticule or a grid. The vector layer can be geocoded even though it represents a graticule. The grid or graticule is created based on image extents and increments in the X and Y directions.

The GRIDTYPE (Grid Type) parameter specifies whether the new grid is geocoded (easting/northing) or geographic (lat/long). A geocoded grid has vector lines parallel to its coordinate system; when the input image has a UTM projection, for example, the output grid will follow lines of constant UTM northing or easting. A geographic grid is actually a "graticule", where the vector lines correspond to lines of constant longitude or latitude.

A geographic grid can be generated from an image with geographic or projected coordinates. A geocoded grid can only be generated from an image with projected coordinates, and not from geographic coordinates.

The X and Y increments can be specified in either Geocoded or Geographic units, depending on the Grid Type. If the Grid Type is geocoded, the increments will be geocoded units (for example, meters or feet). An increment of 1000 m creates a grid line every 1000 m. If the Grid Type is geographic, the increment units are decimal degrees. An increment of 1 (0.01 decimal degrees) creates a grid line every 36 seconds.