TOVS Path-P IDL Tools Tutorial

Introduction  |   Getting Started  |   Tutorial:  1  2  3  4  |   Example:  1  2  3  4  |   Extended Help

Getting Started

These IDL tools have been written for use with IDL 6.0 or later and have been tested on Unix and Windows machines.

The IDL tools require that the TOVS Pathfinder Path-P Daily and Monthly Polar Gridded Atmospheric Parameters data files to be organized in a specific way on your disk. All the data files must be placed under the same base directory. The ancillary data files (tpp_n100_9999999_ancil.hdf for the Northern Hemisphere and tpp_s100_9999999_ancil.hdf for the Southern Hemisphere) must be in the base directory, while the daily data files must be in yearly subdirectories under the base directory. The directory name of each yearly subdirectory must be the 4-digit year. The easiest way to ensure that your directory is set up properly is to download the daily data tar files to the base directory and untar them from there. The yearly subdirectories will be created automatically.

Example:

To download and run the tools from the TOVS Path-P FTP site, please perform the following steps. Implementation of each step will vary depending on your operating system and shell.

  1. Download tools from the TOVS Path-P FTP site
  2. Add the path to the tools to your IDL path
  3. Set the startup file
  4. Pick a fixed-width font for your output log
  5. Restart IDL
  6. Begin using the tools with the tutorial
  1. Download tools from the TOVS Path-P site
     
  2. Add the path to the tools to your IDL path.

    Note: Be sure to add the new path without eliminating any existing paths.
     
  3. Set the startup file.

    There are two different version of the startup file. A Unix version called unixstrt.pro and a Windows version called winstrt.pro. When you use the startup file, IDL will compile each of the tool's programs in the correct order and will set the device visual so that the display colors behave correctly. The tools were built assuming that PseudoColor is used on Unix systems and decomposed color is turned off on Windows systems. Unexpected results will occur on the color displays if you run the tools using TrueColor. If you use a customized startup file, you may wish to merge the startup file provided with your own customizations.
     
  4. Pick a fixed-width font for your output log.

    Some of the tools display text output in the IDL window. The output will be easier to read if you are using a fixed-width font such as Courier or Courier New.
     
  5. Restart IDL.

    For these changes to take affect, you must restart IDL. After restarting, your display should look similar to the following:

    IDL Version 6.x. Research Systems, Inc.
    Installation number: xxxx.
    Licensed for use by: your company/institution

    For basic information, enter "IDLInfo" at the IDL> prompt.
    % Compiled module: COLORBAR.
    % Compiled module: BLANK_LEGEND.
    % Compiled module: MAKE_LEGEND.
    % Compiled module: PAINT_LEGEND.
    % Compiled module: SNOWICE_LEGEND.
    % Compiled module: OCEAN_LEGEND.
    % Compiled module: SSMI_CONVERT.
    % Compiled module: SSMI_INVERSE.
    % Compiled module: EASE_CONVERT.
    % Compiled module: EASE_INVERSE.
    % Compiled module: PPPU_ADD_SDS.
    % Compiled module: PPPU_FILES.
    % Compiled module: PPPU_GET_SDS_DESCRIPTIONS.
    % Compiled module: PPPU_IS_ANCILLARY_SDS.
    % Compiled module: PPPU_YYYYDOY_TO_JULDAY.
    % Compiled module: PPP_READ.
    % Compiled module: PPP_TOC.
    % Compiled module: PPP_EXTRACT.
    % Compiled module: PPP_STATS.
    % Compiled module: PPP_PLATFORM.
    % Compiled module: PPP_PLOT.
    % Compiled module: PPP_PLOT_XPARAMS.
    % Compiled module: PPP_COMPARE.
    % Compiled module: PPP_SHOW.
    % Compiled module: PPP_ANIMATE.
    % Compiled module: PPP_SAVE.
    % Compiled module: PPP_RESTORE.
    % Compiled module: PLAY_GIF.
    % Compiled module: PPP_PLATFORM

    The Polar Pathfinder P-cube/TOVS IDL access routines are now installed.

    Please refer to index.html in the HTML documentation,
    for more information about these tools, including extended
    help documentation.

    Select Platform:
    Enter 1 for P-cube
    Enter 2 for TOVS Northern Hemisphere Path-P Daily
    Enter 3 for TOVS Northern Hemisphere Path-P Monthly
    Enter 4 for TOVS Southern Hemisphere Path-P Daily
    :

     The prompt at the end of the installation requires you to select the data you want to visualize. For this tutorial and data set, you will only be concerned with modes 2, 3, and 4 (P-cube is a different data set not discussed in this tutorial). Note: You can use the procedure ppp_platform at any time to switch data sets.

    If you see compilation errors during startup, the first thing to check is if you have overwritten your current IDL_PATH (instead of appending the IDL tools directory to your existing path, thereby causing IDL to lose track of standard IDL functions). The way to check this is to print the value of IDL_PATH by printing the system variable !path and to confirm that the output looks similar to the following:

    IDL> print, !path
    /usr/me/tovs/IDL_tools:+/usr/local/rsi/idl5.1/idl_5.1/lib:+/usr/local/rsi/idl5.1/idl_5.1/examples

    And not like this:

    IDL> print, !path
    /usr/me/tovs/IDL_tools

    If you did overwrite your IDL_PATH, you must start a new window to get the original path back before re-executing the setenv commands above.
     
  6. Begin using the tools with the tutorial.

    Please refer to the Extended Help documentation and the Tutorial for examples and suggestions on how to run the tools.