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SDgetcal/sfgcal

intn SDgetcal(int32 sds_id, float64 *cal, float64 *cal_err, float64 *offset, float64 *offset_err, int32 *data_type)
sds_id

IN:

Dataset identifier returned from SDselect

cal

OUT:

Calibration factor

cal_err

OUT:

Calibration error

offset

OUT:

Uncalibrated offset

offset_err

OUT:

Uncalibrated offset error

data_type

OUT:

Data type of uncalibrated data

Purpose

Retrieves the calibration information associated with the specified dataset.

Return value

Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.

Description

SDgetcal reads the calibration record attached to a dataset. A calibration record contains four 64-bit floating point values followed by a 32-bit integer, to be interpreted as follows:

cal calibration factor

cal_err calibration error

offset uncalibrated offset

offset_err uncalibrated offset error

data_type data type of uncalibrated data

The relationship between a value iy stored in a dataset and the actual value is defined as: y = cal * (iy - offset).

The variable offset_err contains a potential error of offset, and cal_err contains a potential error of cal. Currently the calibration record is provided for information only. The SD interface performs no operations on the data based on the calibration tag.

FORTRAN

integer function sfgcal(sds_id, cal, cal_err, offset, offset_err, data_type)

integer sds_id, data_type

real*8 cal, cal_err, offset, offset_err



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HDF User's Reference Manual, Draft 06/09/97, NCSA HDF Development Group.