User's Guide

GETCALTYPE

Get calibration type

Function:

Get calibration type. This routine may be called to determine the calibration technique historically employed (based on satellite number and acquisition date).

Parameters:

SCENEID
Scene identifier. The 16-character scene identifier to be calibrated.

CALTYPE
Calibration type. The calibration technique historically used for scene SCENEID will be returned in this parameter. Typical return values are 'RAO', 'VERMOTE', 'TEILLET', and 'PRELAUNCH'.

Examples:

  1. LAS> getcaltype sceneid="ah16030201231201" caltype=calt

    The acquisition date (03/02/01) and satellite number (16) are extracted from the scene identifier. The calibration technique historically used for this number and date will be returned in the local TAE variable 'calt'.

Description/Algorithm:

The satellite number and date of acquisition are determined from the specified scene identifier. The appropriate table is read to determine if a calibration technique is available for the specified acquisition date. If the calibration technique historically used is found in the table, it is returned; otherwise, an error status is returned.

Nonfatal Error Messages:

    None.

Fatal Error Messages:

  1. [getcaltype-fatal] Fatal error encountered

    A fatal error was encountered during processing. Processing is terminated. The error message that is displayed immediately preceding this message is the specific error that was encountered.

  2. [getcaltype-tab] Error retrieving value of ADAPSTABLES

    The value of the environment variable ADAPSTABLES could not be determined. Ensure that this variable has been defined.

  3. [getcaltype-open] Error opening the calibration table

    The appropriate table could not be opened. Ensure that the table 'noaaXX.caltype' exists in ADAPSTABLES with the proper permissions (where XX is the NOAA satellite number).

  4. [getcaltype-read] Error reading the header information

    An error occurred while reading the header of the calibration file. Ensure that the file contains two lines of header information.

  5. [getcaltype-calt] Error determining calibration technique

    An error was encountered while reading the calibration file to determine the calibration technique to return. Verify that the file specifies a technique for the time frame specified by the scene identifier.

  6. [getcaltype-tae] Error returning parameter to TAE

    An error was encountered while attempting to return the calibration type to TAE. Contact the system administrator if this error persists.

  7. [getcaltype-nova] Calibration type unavailable

    No calibration type was specified in the tables for the NOAA satellite on the acquisition day. Verify that the proper scene identifier has been specified.

User Notes:

  1. The user is often unsure of the most appropriate calibration technique historically applied to an AVHRR scene (contingent upon the NOAA satellite number and the date of acquisition). This routine will return this technique.

  2. The calibration type tables have been arranged so that a value of 'prelaunch' will be returned for the first 6 months of the life of each satellite. This arbitrary time frame is used because the actual transition time (transition from using prelaunch coefficients to something other than prelaunch coefficients) has not been recorded in the past. In the future, this transition time will be recorded by these tables.