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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:

Data set identifier returned by SDcreate or 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 a data set.

Return value

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

Description

SDgetcal reads the calibration record attached to the data set identified by the parameter sds_id. A calibration record is comprised of four 64-bit floating point values followed by a 32-bit integer. The information is listed in the following table:


cal


calibration factor


cal_err


calibration error


offset


uncalibrated offset


offset_err


uncalibrated offset error


data_type


data type of the uncalibrated data

The relationship between a calibrated value cal_value and the original value orig_value is defined as orig_value = cal * (cal_value - 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 Reference Manual - 04/08/98, NCSA HDF Development Group.