NAME

fgts -- Convert coordinates from Gnomonic Direction Cosines to Spacecraft.

USAGE

fgts input_table

DESCRIPTION

This filter searches data tables for Gnomonic Direction Cosines, i.e., those rows in which the FRAME column contains G. When Gnomonic coordinates are found, the X, Y, and associated covariances are converted to Spacecraft coordinates using quaternion multiplication. (The transforming quaternion is obtained from data columns Q1, Q2, Q3, and Q4.)

A star is skipped if an error occurs when retrieving its position information. An error in retreiving the covariance will cause the covariance transformation to be skipped. If a transformation error causes a line to be skipped, the offending column will contain the value INDEF. In all cases, the FRAME column will contain an S.

Fgts uses the following columns:

	INPUT			OUTPUT
	-----			------
	X			X
	Y			Y
	X_X			X_X
	Y_Y			Y_Y
	X_Y			X_Y
	FRAME			FRAME
	RAV1,DECV1,ROLLV3	Q1,Q2,Q3,Q4

PARAMETERS

input_table [file name template]

Name of the table that is to have its coordinates converted from Gnomonic to Spacecraft. This can be either the file name of an individual table or a list of data tables that are to be converted.

(output_table) [file name template]

If the new_table parameter is set to true, then the user will be prompted to enter an output file name. The output file will contain the results of the coordinate transformation process, avoiding the need to overwrite original data tables. If this flag is not set, files will be processed in place. Output_table will accept a file name template when processing a list of data tables.

(new_table = no) [boolean]

Create a new file for the output table? Prevents overwriting the original data table.

(verbose = yes) [boolean]

Print the transformed coordinates to the terminal screen?

EXAMPLES

1. Convert a data table from Gnomonic to Spacecraft coordinates.

	cl> fgts intable

2. Convert a data table from Gnomonic to Spacecraft coordinates, and create a new file for the output table.

	cl> fgts intable new_table+ output_table="outtable"

3. Convert coordinates in all tables having the suffix .tab.

	cl> fgts *.tab

BUGS

SEE ALSO