NDF2ASCII

Converts an NDF to a text file

Description:

This application converts an NDF to a Fortran text file. Only one of the array components may be copied to the output file. Preceding the data there is an optional header consisting of either the FITS extension with the values of certain keywords replaced by information derived from the NDF, or a minimal FITS header also derived from the NDF. The output file uses LIST carriagecontrol.

Usage:

ndf2ascii in out [comp] [reclen] noperec=?

Parameters:

COMP = LITERAL (Read)
The NDF component to be copied. It may be "Data", "Quality" or "Variance". ["Data"]
FITS = _LOGICAL (Read)
If TRUE, any FITS extension is written to start of the output file, unless there is no extension whereupon a minimal FITS header is written to the ASCII file. [FALSE]
FIXED = _LOGICAL (Read)
When FIXED is TRUE, the output file allocates a fixed number of characters per data value. The number of characters chosen is the minimum that prevents any loss of precision, and hence is dependent on the data type of the NDF array. These widths in characters for each HDS data type are as follows: _UBYTE, 3; _BYTE, 4; _UWORD, 5; _WORD, 6; _INTEGER, 11; _INT64, 20; _REAL, 16; and _DOUBLE, 24. The record length is the product of the number of characters per value plus one (for a delimiting space), times the number of values per record given by parameter NOPEREC, up to a maximum of 512.

When FIXED is FALSE, data values are packed as efficiently as possible within each record. The length of each record is given by Parameter RECLEN. [FALSE]

IN = NDF (Read)
Input NDF data structure. The suggested default is the current NDF if one exists, otherwise it is the current value.
NOPEREC = _INTEGER (Read)
The number of data values per record of the output file, when FIXED is TRUE. It should be positive on UNIX platforms. The suggested default is the current value, or 8 when there is not one. The upper limit is given by 512 divided by the number of characters per value plus 1 (see Parameter FIXED).
OUT = FILENAME (Write)
Name of the output formatted Fortran file. The file will normally have variable-length records when there is a header, but always fixed-length records when there is no header.
RECLEN = _INTEGER (Read)
The maximum record length in bytes (characters) of the output file. This has a maximum length of 512 (for efficiency reasons), and must be greater than 31 on UNIX systems. The lower limit is further increased to 80 when there is a FITS header to be copied. It is only used when FIXED is FALSE and will default to the current value, or 132 if there is no current value. []

Examples:

ndf2ascii cluster cluster.dat
This copies the data array of the NDF called cluster to a text file called cluster.dat. The maximum recordlength of cluster.dat is 132 bytes, and the data values are packed into these records as efficiently as possible.
ndf2ascii cluster cluster.dat v
This copies the variance of the NDF called cluster to a text file called cluster.dat. The maximum recordlength of cluster.dat is 132 bytes, and the variance values are packed into these records as efficiently as possible.
ndf2ascii cluster cluster.dat fixed noperec=12
This copies the data array of the NDF called cluster to a text file called cluster.dat. There are twelve data values per record in cluster.dat.
ndf2ascii out=ndf234.dat fits reclen=80 in=@234
This copies the data array of the NDF called 234 to a text file called ndf234.dat. The maximum recordlength of ndf234.dat is 80 bytes, and the data values are packed into these records as efficiently as possible. If there is a FITS extension, it is copied to ndf234.dat with substitution of certain keywords, otherwise a minimal FITS header is produced.

Notes:

The details of the conversion are as follows:

Related Applications

CONVERT: ASCII2NDF; Kappa: TRANDAT; FIGARO: ASCIN and ASCOUT.

Implementation Status: