ISOCAM Interactive Analysis User's Manual Version 5.0 - ISO - ESA

19.6. ADVANCED SLICING WITH X SLICER 227
19.6.6.3 Selecting and Merging SCDs
The x handle slice window allows you to select SCDs one by one. To select or unselect the
SCDs, just click on the radio button on the SCD. The x handle slice window allows you also
to ‘merge’ SCDs. Merging two SCDs is simply to glue them together in order to have only one.
two rules must be followed :
• you can ONLY MERGE SELECTED SCDs
• you can ONLY MERGE CONTINUOUS SCDs, i.e. no hole in the data.
If you do not follow these rule, it is very likely that the slicer will crash.
Merging SCDs is very interesting if you work on data that have suffered from telemetry
drop-outs, for example if you have ‘false’ M and N RASTER values (see above). If this is the
case, something like the following is displayed:
SCD number no. frames M RASTER N RASTER
i 3 3 2
i+1 2 0 0
i+2 7 3 2
Select the SCDs i, i+1 and i+2, then press the ‘Merge i and i+1’ button and the ‘Merge i+1
and i+2’ button. The error will be corrected.
19.6.6.4 Build only SCDs of SPD flavor
If your observation is done using the ‘Normal’ mode, you receive two frames per image: a Reset
frame and a End Of Integration (EOI) frame. If you do not ask for it, the x slicer will create
SCDs of ERD flavor, i.e. with EOI end Reset frames. If you ask for it, it makes the slicer call
the erdtospd routine that will translate this format into real images (it is only a subtraction
LW and little more complicated for the SW).
19.6.6.5 DSD files
DSDs are Diagnostic Specific Data files. These files are interesting only for the ISOCAM experts
in case of an instrument problem. Fortunately there was no ISOCAM problems during the
mission, so there was no reason to access these files. CIA contains some routines (ia all status,
ia temp status, . . . ) to perform some checks on the DSD files.
19.6.6.6 Saving slicer file
The use of this button is important if you work on big datasets (see below).
19.6.6.7 Entering names and directories
At the point of really creating your SCDs (after hitting the ‘Continue’ button) you will be asked
to enter a name and a directory.
AGAIN DO NOT FORGET TO HIT THE RETURN KEY, otherwise x slicer will not take
into account what you entered. . .