TRIG - Performs a trigonometric transformation on a NDF

Description:

This routine copies the supplied input NDF , performing a specified trigonometric operation (sine, tangent, etc.) on each value in the DATA array. The VARIANCE  component, if present, is modified appropriately. Pixels for which the required value is undefined, or outside the numerical range of the NDFs data type, are set bad in the output.

Usage:

trig in trigfunc out title

Parameters:

IN = NDF (Read)

The input NDF structure.

OUT = NDF (Write)

The output NDF structure.

TRIGFUNC = LITERAL (Read)

Trigonometrical function to be applied. The options are as follows.

• "ACOS" -- arc-cosine (radians)

• "ACOSD" -- arc-cosine (degrees)

• "ASIN" -- arc-sine (radians)

• "ASIND" -- arc-sine (degrees)

• "ATAN" -- arc-tangent (radians)

• "ATAND" -- arc-tangent (degrees)

• "COS" -- cosine (radians)

• "COSD" -- cosine (degrees)

• "SIN" -- sine (radians)

• "SIND" -- sine (degrees)

• "TAN" -- tangent (radians)

• "TAND" -- tangent (degrees)

TITLE = LITERAL (Read)

A title for the output NDF. A null value will cause the title of the NDF supplied for Parameter IN to be used instead. [!]

Examples:

trig sindata asind data

Take the arc-sine of the data values in the NDF called sindata, and store the results (in degrees) in the NDF called data.

trig sindata asin data

As above, but the output values are stored in radians.

Related Applications :

KAPPA: ADD, CADD, CMULT, CDIV, CSUB, DIV, MATHS, MULT, SUB.

Implementation Status:

• This routine correctly processes the AXIS, DATA, QUALITY, LABEL, TITLE, UNITS, HISTORY, WCS, and VARIANCE  components of an NDF data structure and propagates all extensions.

• Processing of bad pixels and automatic quality masking are supported.

• All non-complex numeric data types can be handled. Arithmetic is performed using single-precision floating point, or double precision, if appropriate, but the numeric type of the input pixels is preserved in the output NDF.