Anatomy of a SURF task

SURF tasks follow the same general format internally:

1. Request the messaging level from the parameter system (MSG_LEVEL).
2. Read in some information concerning the object name, observation mode and run number and write this to the screen (at normal messaging level) to keep the user informed.
3. Check the history component to make sure that the correct tasks have been run prior to running the current task. This always contains a check to see that the reduce_switch task has been run on the data.
4. Check the dimensions of the data array, the LST_STRT array and the DEM_PNTR arrays.
5. Retrieve information from NDF extensions (see e.g. SCULIB_GET_BOL_DESC, SCULIB_GET_JIGGLE). [as required]
6. If required, construct an output name based on the input filename (SCULIB_CONSTRUCT_OUT). The output file is usually propogated from the input file using NDF_PROP.
7. Do whatever has to be done.
8. Shut down NDF, free memory, free locators.