1.1 Accessing the Yohkoh Data (YODAT)

1. Shows what data are on line
2. Lets you select specific files to read and display
3. Reads the ROADMAP for the selected files
4. If you select data sets to be read, it creates the variables data and index which you can then manipulate using IDL or other higher-level Yohkoh routines.

This procedure is run by typing (make sure that yodat is in lower case if you are running on a Unix or Ultrix machine):
IDL> .run yodat
  The prompt that you will receive will look something like this:

% Compiled module: $MAIN$.
               *******  YODAT V9.2 (7-Jul-93)  *******

It is possible to have YODAT extract every "n"th dataset by setting
the variable QYODAT_NSAMP to 1.  You will be asked one extra question

It is possible to read the Ground Based Observation (GBO) FITS files
by using a command like: MENU g*
          gb_ files are from Big Bear, gk_ are from Kitt Peak
RFITS will be called with /SCALE option if QYODAT_SCALE is set to 1

Enter MENU if you want to use the filenames menu option
Enter SAME if you want to access the same fileID for a different instrument
Enter MANY if you want to use menu option and extract many files
Enter TIME if you want to enter the start/end time to extract
Enter QUIT to abort out of YODAT

Enter file name (or wild cards)

• You can type the full file name, including the directory if the data file does not exist in the default directory. Wild cards are acceptable (e.g., spr9301*.*).
• You can use the MENU option to get a listing of all of the files that are on-line (this option uses the output of DATA_PATHS to get a list   of the data directories). For example, if you type menu spr*, you will get a list of all SPR files that are on-line. Or if you type menu bda9207* you get a list of all BDA files for Jul-92 that are on-line. You can only extract one file with the MENU option so click on the one file you wish to read.
• You can use the MANY option to select several files. This option is also menu driven, and is similar to the MENU option but you can select multiple files. After you have selected all the files you want to read, click on QUIT/EXIT.
• If you have already read a file, and wish to get the data for the same time but from a different experiment, you can use the SAME option. For example, if you have just read spr911115.2141, and want to get the BDA file for that orbit, type same bda.
• Once you have selected a file, you can re-run YODAT and simply hit RETURN and the same file is selected again so you can select a different set of down-line options.
• If you type quit, then YODAT will be stopped.
• If you are running YODAT over the network, then it might not be practical to run options which create an X-window. You can specify the file and directory using wild cards. The list of selected files will then appear with a number next to each file. You can then enter the starting and ending file number to select a set of files. For example, you could type
  ``/yd*/*/spr930623*'' or ``/yd6/flares/spr91*''.

The ``MENU'' and ``MANY'' options search all data directories which are returned by the function DATA_PATHS. At ISAS and LPARL this routine automatically checks for new data directories that are on-line, in addition to some ``hardwired'' directories which it always checks. It is possible for a user to add directories to the list which DATA_PATHS returns by using the routine NEW_DPATH. In the following example, the user adds the directory ``/yd3/morrison/agu_paper'' to the list of directories which will be checked by YODAT.
IDL> new_dpath, '/yd3/morrison/agu_paper'
    The second step in accessing any data set is to perform a quick review of the data available, and select the data sets to be read. The options for selecting the data are listed below.

Enter the number of data sets to extract
   * If you enter 0, all datasets will be extracted
   * If you enter -99, then it uses the datasets specified in variable "SS"
   * If you enter -888, then the file is not read
   * For SXT, enter a negative # (from -1 to -13) to access only that seq#
   * For SXT, enter -777 for sequence menu option
              Enter -776 to use "show_obs3" and select
              Enter -775 to use "plot_fov" and select
              Enter -774 to list the sequence summary
              Enter -773 to use "show_obs4" and select
              Enter -772 to use SSWHERE to select
   * For HXT, enter -666 to plot and select on SUM_L light curve
              Enter -665 to plot and select on SUM_M1 light curve
              Enter -664 to plot and select on SUM_M2 light curve
              Enter -663 to plot and select on SUM_H light curve
   * For WBS, enter -555 to plot and select on SXS1 light curve
              Enter -554 to plot and select on SXS2 light curve
              Enter -553 to plot and select on HXS light curve
   * For BCS, enter -444 to plot and select on S XV light curve
              Enter -443 to plot and select on Ca XIX light curve
              Enter -442 to plot and select on Fe XXV light curve
              Enter -441 to plot and select on FE XXVI light curve
   * For any, enter -333 to extract only flare mode data

If you selected data to be read, then the results are saved in the following variables:

For SXT options `SHOW_OBS3', `SHOW_OBS4', and `SSWHERE', see the description in the Reference Guide. The light curve options (all of the 400, 500, and 600 series) will show a light curve of the selected channel. YODAT will prompt you with the instructions at each step. It is possible to select the range in time you wish to look at by:

1. Click with the left button at the starting time
2. Click with the right button at the ending time
3. Click with the middle button to exit

An example of how one would use the 99 option is:

1. Run YODAT to select the file and to read the roadmap.
2. Exit out of YODAT with the 888 option.
3. Select the data to be extract using some high-level routine or simple IDL `where' commands. Put the results in the variable `ss'.
4. Run YODAT again selecting the same file by just hitting RETURN.
5. Selecting option 99.

• 1.1.1 Most Common BCS Display Routines
• 1.1.2 Most Common HXT Display Routines
• 1.1.3 Most Common SXT Display Routines
• 1.1.4 Most Common WBS Display Routines
• 1.1.5 Advanced YODAT Options