source: trunk/SRC/Documentation/xmldoc/mini_notice.xml @ 145

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<!--

./SAXO_DIR/SRC/Documentation/xmldoc/mini_notice.xml

update :
fplod 2006-07-20T08:45:14Z aedon.locean-ipsl.upmc.fr (Darwin)
. creation by hand made migration from mini_notice.html to XML/Docbook
. installation part has been removed
. add images
++ fake graphics callouts see forxxxdoc.sh

-->
<article lang="en">
<title>
Mini Guide for Basic Commands in the XXX Program
</title>
  <articleinfo>
    <authorgroup>
      <author><firstname>Sébastien</firstname><surname>Masson</surname><email>Sebastien.Masson_at_locean-ipsl.upmc.fr</email></author>
      <author><firstname>Albert</firstname><surname>Fisher</surname></author>
      <author><firstname>Françoise</firstname><surname>Pinsard</surname><email>Francoise.Pinsard_at_locean-ipsl.upmc.fr</email></author>
      <author><firstname>Steve</firstname><surname>Navarro</surname></author>
    </authorgroup>
    <keywordset>
      <keyword>idl</keyword>
      <keyword>SAXO</keyword>
      <keyword>xxx</keyword>
    </keywordset>
    <revhistory>
      <revision>
        <revnumber>0.0</revnumber>
        <date>May 29, 2000</date>
        <revremark>French release by Sébastien Masson</revremark>
      </revision>
      <revision>
        <revnumber>0.1</revnumber>
        <date>July, 2002</date>
        <revremark>Translation by Albert Fisher</revremark>
      </revision>
      <revision>
        <revnumber>0.2</revnumber>
        <date>July 20, 2006</date>
        <revremark>HTML to XML/Docbook migration by Françoise Pinsard</revremark>
      </revision>
     </revhistory>
     <pubdate>$Id$</pubdate>
  </articleinfo>


<!--
La partie suivante n'a plus tellement de sens maintenant que tout SAXO est disponible sur forge
<para>
Where to find the source code
</para>
The scripts are available in the IDL_29_5_2000 directory.
</para>
<para>
In this directory are
<itemizedlist>
<listitem><para>a tar file IDL_29_5_2000.tar with all the files</para></listitem>
<listitem><para>the scripts in ASCII, in subdirectories by theme</para></listitem>
</itemizedlist>

<para>
This IDL_29_5_2000 directory is available:
<itemizedlist>
<listitem><para>at LODYC: adonis.lodyc.jussieu.fr:/usr/home/smasson/IDL_29_5_2000</para></listitem>
<listitem><para>at IPSL: cook.ipsl.jussieu.fr:/home/smlod/IDL_29_5_2000</para></listitem>
<listitem><para>at IDRIS: rhodes.idris.fr:/home/rech/eee/reee217/IDL_29_5_2000</para></listitem>
<listitem><para>on the anonymous ftp site of LODYC (contact <ulink url="mailto:smasson@lodyc.jussieu.fr">smasson@lodyc.jussieu.fr</ulink>
for access).</para></listitem>
<listitem><para>soon, from <ulink url="http://www.lodyc.jussieu.fr/~opatlod/SAXO/"/></para></listitem>
</itemizedlist>
</para>
<para>
This mini guide is also found in the IDL_29_5_2000 directory, in
different formats.  It is also consultable on the web at:
</para>
<para>
<ulink url="http://www.ipsl.jussieu.fr/~smlod/mini_notice.html"/>
</para>

-->
<sect1 id="intro"><title>Introduction and assumptions</title>

<para>
This micro guide is unfortunately not a user's guide for all the
scripts that have been written for IDL (version 5.2 or higher
required). The goal is simply to clarify a few points on the use of the <filename>xxx.pro</filename>
program.
</para>
<para>
For further help on the furnished scripts, here are
several possibilities:

<itemizedlist>
<listitem><para>execute in IDL the command
  <screen format="linespecific">
<prompt>&promptidl;</prompt> <userinput>xhelp, '<replaceable>script_name</replaceable>'</userinput>
</screen>
</para></listitem>
<listitem><para>consult the IDL online help for scripts whose source is unavailable</para></listitem>
<listitem><para>
subscribe to the mailing list for updates and user questions/responses
</para>
<para>
to subscribe, send a mail to: <ulink url="mailto:majordomo@lmd.jussieu.fr">majordomo@lmd.jussieu.fr</ulink>
with no subject, containing the message:
<userinput>subscribe forum-idl <replaceable>e-mail address</replaceable></userinput>
</para></listitem>
<listitem><para>consult the archives of this mail list:
    <ulink url="http://www.lmd.jussieu.fr/archives/form-idl/last/mail1.html"/></para></listitem>
<listitem><para>consult in desperation the feeble web pages we have started to write
  (while waiting for something better)
  <ulink url="http://www.ipsl.jussieu.fr/~smlod/"/></para></listitem>
<listitem><para>wait until we write a full user's manual!</para></listitem>
</itemizedlist>
</para>

<para>
The XXX widget is a layer on top of the scripts in the <application>SAXO</application> package
(themselves layered on top of IDL). It is designed to permit the
visualization and rapid exploration of data, offering a maximum in
options, while not necessarily all those offered by the package and by
IDL.
</para>
<para>
Based on the use of files in the NetCDF format, it can easily work
with other file formats.  For this, all that is necessary is to write
an IDL function capable of extracting a matrix from a file as a
function of the following parameters: the variable name, two dates, an
experiment name, and a domain.
</para>
<para>
Developed to visualize the output of the OPA model, the <application>SAXO</application> package was
conceived to work on C grids.  To use it on grids where the T, U, and
V points are the same, one must nevertheless declare the parameters of
the grid that correspond to the U and V points.  Careful, for this
type of discretization, the calculation scripts of type <filename>div.pro</filename> and
<filename>curl.pro</filename> are wrong.
</para>
<para>
The averaging routines are not adapted to warped grids, they sum
following the i, j, and k indices, weighting each point by scale
factors and the land-sea mask.  Slices and Hovmoellers do not work in
the diagonal, but are always done following i, j, or k.  When a domain
is given to one of the scripts, an average over the domain in the
directions perpendicular to that displayed is automatically made before
display.
</para>
<para>
Before continuing on to the practical part of this guide, the
installation and use of the <application>SAXO</application> package, I'd like to thank Guillaume
Roullet, who also participated in the writing of the scripts in the
package (notably the drawing of vectors on warped grids).
</para>
</sect1>

<sect1 id="beforefirststeps">
<title>Before this</title>
<para>
In this document, we supposed that you followed <ulink url="getsaxo.html?format=raw">Get SAXO</ulink> recommandations.
</para>
</sect1>


<sect1 id="initfiles"><title>Install the files <filename>init.pro</filename> and
<filename>initgrid.pro</filename></title>

<para>
This version of the <application>SAXO</application> package depends a certain number of common
variables that are primarily environmental parameters (working paths,
color management, Postscript formatting) and the parameters of the
grid on which you are working (longitude, latitude, depth, land-sea
mask, scale factors, position of the zoom in relation to the original
grid).
</para>
<para>
These two types of parameters are kept separately:
<itemizedlist>
<listitem><para>environmental parameters are defined at the very beginning of the
IDL session, and are in principle never changed.  They are initialized
by the <filename>init.pro</filename> script.</para></listitem>
<listitem><para>Those that belong to the grid are reinitialized every time the
grid is changed.  They can therefore be called at any time during a
session. These parameters are initialized by the <filename>initgrid.pro</filename>
scripts, and are specific to each particular grid.
</para>
<para>
For example: <filename>initorca.pro</filename> for the ORCA 2&deg; grid,
<filename>initorca05.pro</filename> for
the ORCA 0.5&deg; grid, or <filename>initorcapac.pro</filename> for the ORCA grid zoomed on
the Pacific.</para></listitem>
</itemizedlist>
</para>
<para>
To begin, one must therefore copy <filename><replaceable>packagedir</replaceable>/INIT/init.pro</filename>
into <replaceable>homedir</replaceable>, and create in <replaceable>homedir</replaceable> a script of the
type <filename>initgrid.pro</filename>.
</para>

<!-- ++ n'a plus rien à faire ici
<sect2 id="modifinit"><title>Modification of the <filename>init.pro</filename> script</title>

<para>
It is necessary to personalize the lines that correspond to the 6
directories defined in &sect; 1.1.  That is:
<itemizedlist>
<listitem><para>The definition of !path.</para><para>
The first expand_path must contain <replaceable>homedir</replaceable>, the second
<replaceable>packagedir</replaceable>.  The directory declaration must be preceded by a +
sign, and must take the form of a character chain. The + sign
specifies that subdirectories must also be considered.  For those
working on a Mac, <literallayout>"+':'+"</literallayout> must be replaced by <literallayout>"+','+"</literallayout> and for Windows
by <literallayout>"+';'+"</literallayout>.</para>
<warning>
<para>
In their definition, the directories must not finish with the
directory separation character ("/" under UNIX/Linux).
</para>
</warning>
</listitem>
<listitem><para>Definition of the rest of the directories:</para><para>
Define as necessary the variables homedir, workdir, iodir, animdir,
psdir, and imagedir.</para>
<warning>
<para>
Despite precautions taken, in order to avoid bugs it is
recommended that these directories be defined with the directory
separation character as the final character ("/" under UNIX/Linux).
</para>
</warning>
</listitem>
</itemizedlist>
</para>
<note>
<para>
Depending on the resolution of your screen and the type of
machine used, it is possible that the graphics window which is created
will be too large.  If this is the case, change the ccwindowsize
variable which is a multiplicative coefficient applied to the window
size.
</para>
</note>
</sect2>
-->
<sect2 id="modifinitgrid"><title>Modification or creation of the <filename>initgrid.pro</filename> script</title>

<para>
In the <replaceable>packagedir</replaceable>/INIT directory you will find a certain
number of scripts associated with the latest grids on which I've
worked.  If you are also working on one of these grids, for example
ORCA, copy the file  <filename><replaceable>packagedir</replaceable>/INIT/initorca.pro</filename> to your
<replaceable>homedir</replaceable>.  If not, copy it nevertheless to use as a model.  In
the file <filename>initgrid.pro</filename>, adjust the zoom parameters (if it has not
already been done).
</para>
<para>
Careful: unlike in previous versions of the <application>SAXO</application> package, all the zoom
parameters must be defined.  If you do not know them in advance,
define their values to be -1.
</para>
<para>
In the rest of the script, define iodir as <replaceable>iodir</replaceable>, and verify
the name of the mask file, if one exists.
</para>
</sect2>
</sect1>
<sect1 id="introxxx"><title>Starting the <application>SAXO</application> package and an explanation of the XXX widget functions</title>
<sect2 id="launchxxx"><title>Launching XXX</title>

<para>
The first command to type is

  <screen format="linespecific">
<prompt>&promptidl;</prompt> <userinput>@init</userinput>
</screen>

</para>
<para>
Afterwards, to work directly with XXX, type:

  <screen format="linespecific">

<prompt>&promptidl;</prompt> <userinput>xxx</userinput>
</screen>

</para>

<para>
To work without the XXX interface, initialize a grid

  <screen format="linespecific">

<prompt>&promptidl;</prompt> <userinput>@initgrid</userinput>
</screen>


</para>
<para>
A window will open with 2 lines to complete.
<figure id="fig_xxx_1">
<title>Window xxx 1</title>
<mediaobjectco>
<!-- ++ pas encore au point cf. forxxxdoc.sh !! -->
<imageobjectco>
<areaspec units="calspair">
<area id="datafile" coords="96,1779 9903,2912"/>
<area id="initfile" coords="96,4854 9903,6472"/>
</areaspec>
<imageobject>
<imagedata fileref="figpng/xxx_1_complete.png"/> <!-- ++ instead of xxx_1.png -->
</imageobject>
<calloutlist>
<callout arearefs="datafile">
<para>datafile</para>
</callout>
<callout arearefs="initfile">
<para>initfile</para>
</callout>
</calloutlist>
</imageobjectco>
<!-- ++ si on met textobject, on ne voit plus l'image !!
<textobject>[plot figpng/xxx_1_complete.png]</textobject>
-->
</mediaobjectco>
</figure>
</para>
<para>
These lines must contain
the address of a file.  The name can be typed directly in the window
provided, or selected with the help of the <guibutton>browse</guibutton> button.  The first
line must contain the name of the data file, the second the name of
the <filename>initgrid.pro</filename> script which will permit the reading and processing of the
grid associated with the data file.
</para>
<para>
Once these two lines have been completed, click on <guibutton>let's go</guibutton>.  Two
other windows will then open, giving you the parameters for reading
the grid and the file (these parameters are read in the <filename>initgrid.pro</filename>
script).  Click twice on <guibutton>OK</guibutton>.
</para>
</sect2>
<sect2 id="wigdets"><title>An explanation of the different widgets</title>

<para>
Now the XXX window will open.
<!-- cf example in http://www.docbook.org/tdg/en/html/area.html
sauf que dans l'exemple en question on ne donne que 2 nombres et pas 4
voir aussi message http://www.oasis-open.org/archives/docbook-apps/200501/msg00089.html
peut-etre du nouveau dans les xsl depuis le 16 janvier 2005
peut-être essayé http://lists.kde.org/?l=kde-doc-english&m=112780764426265&w=2
ce produit klickety est installable via fink sous mac
 -->
<figure id="fig_xxx_2">
<title>Window xxx 2</title>
<mediaobjectco>
<!-- ++ pas encore au point cf. forxxxdoc.sh !! -->
<imageobjectco>
<areaspec units="calspair">
<area id="pagelayout" coords="578,873 1651,1269"/>
<area id="calendar" coords="82,2222 1899,2857"/>
<area id="domain" coords="82,3174 2477,6349"/>
<area id="specify" coords="82,7142 2890,7936"/>
</areaspec>
<imageobject>
<imagedata fileref="figpng/xxx_2_complete.png"/> <!-- ++ instead of xxx_2.png -->
</imageobject>
<calloutlist>
<callout arearefs="pagelayout">
<para> Page layout </para>
</callout>
<callout arearefs="calendar">
<para> Calendar </para>
</callout>
<callout arearefs="domain">
<para> Domain </para>
</callout>
<callout arearefs="specify">
<para> Specify </para>
</callout>
</calloutlist>
</imageobjectco>
<!-- ++ si on met textobject, on ne voit plus l'image
<textobject>[plot figpng/xxx_2_complete.png]</textobject>
-->
</mediaobjectco>
</figure>
</para>
<para>
It's configuration will change
depending on whether you are in portrait or in landscape, but here are
the different parts available for your use.
</para>

<sect3 id="menubar"><title>The menu bar made up of 3 submenus</title>
<sect4 id="filesubmenu"><title><guisubmenu>File</guisubmenu> submenu</title>

<para>
<itemizedlist>
<listitem>
<para>
<guimenuitem>Open:</guimenuitem> to open a second file.  Same procedure as during the
launching of XXX.  The new file can be on a different grid, with
different variables, with a different time base.
</para></listitem>
<listitem><para><guimenuitem>New XXX:</guimenuitem> to open a second XXX window identical to the first.</para></listitem>
<listitem><para><guimenuitem>Close:</guimenuitem> to close the XXX window.</para></listitem>
</itemizedlist>
</para>

</sect4>
<sect4 id="saveassubmenu"><title><guisubmenu>Save As</guisubmenu> submenu</title>

<para>
<itemizedlist>
<listitem><para><guimenuitem>Postscript:</guimenuitem> to save in Postscript format</para></listitem>
<listitem><para><guimenuitem>Animations:</guimenuitem> to create an animation from the XXX window.
Careful, the creation of an animation is only possible if none of the
plots have a time axis, and if the plots are all on the same time base
(calendar).  On the other hand, animations of horizontal and vertical
plots, with different color palettes (for those not on an X-terminal),
are possible.</para></listitem>
<listitem><para><guimenuitem>Image:</guimenuitem> to save a gif of the XXX graphics window.</para></listitem>
<listitem><para><guimenuitem>Script:</guimenuitem> to save the command history that has created the
plot.  For example if I save the commands in <filename>xxx_figure.pro</filename>, I can
then launch a new IDL session and type:
  <screen format="linespecific">
<prompt>&promptidl;</prompt> <userinput>@init</userinput>
<prompt>&promptidl;</prompt> <userinput>xxx_figure</userinput>
</screen>
</para>
<para>
and I'll obtain the saved figure.
  <screen format="linespecific">
<prompt>&promptidl;</prompt> <userinput>xxx_figure,/post </userinput>
</screen>
or
  <screen format="linespecific">
<prompt>&promptidl;</prompt> <userinput>@ps</userinput>
</screen>
will then create a Postscript file of the figure.</para><para></para></listitem>
<listitem><para><guimenuitem>Prompt:</guimenuitem> lists in the IDL window the command history that
created the last plot.  Useful primarily for debugging...</para></listitem>
</itemizedlist>
</para>
</sect4>
<sect4 id="flagsubmenu"><title><guisubmenu>Flag options</guisubmenu> submenu</title>

<para>
<itemizedlist>
<listitem><para><guibutton>OK</guibutton> To show/hide the OK button in the upper left corner.</para></listitem>
<listitem><para><guibutton>Portrait/Landscape:</guibutton> changes the configuration of the plot.</para></listitem>
<listitem><para><guibutton>Overlay:</guibutton> to plot contours of a different field on top the
one represented as color-filled contours.  It is necessary to relaunch the
entire plot to make this work!</para></listitem>
<listitem><para><guibutton>Vecteur:</guibutton> to plot a vector field on top of contours. Only
works on horizontal plots (<filename>plt.pro</filename>).  As for Overlay, a relaunch of
the entire plot is necessary.</para></listitem>
<listitem><para><guibutton>Longitude / x index:</guibutton> switches longitude labelling of the plot
subdomain from degrees to indices following i. </para></listitem>
<listitem><para><guibutton>Latitude / y index:</guibutton> switches latitude labelling of the plot
subdomain from degrees to indices following j. </para></listitem>
</itemizedlist>
</para>
</sect4>
</sect3>
<sect3 id="typeplot"><title>What type of plot and where?</title>
<para>
<itemizedlist>
<listitem><para><guibutton>OK</guibutton> Show/hide the OK button in the upper left.  When
present, a click is required to make a new plot appear. Otherwise
each action creates a new plot. </para></listitem>
<listitem><para><guimenuitem>Plot type list:</guimenuitem> allows specification of the type of plot
desired.
</para>
<note>
<para>
If the type <constant>plt</constant> is selected, the selection of plot type
is made by mouse. Cf <xref linkend="mouse"/></para>
</note>
</listitem>
<listitem><para><guimenuitem>Layout configuration:</guimenuitem> specify the number of columns and
rows for plots on the sheet of paper.  There's no code behind the undo
command!  The <guibutton>clear</guibutton> button erases all plots.</para></listitem>
<listitem><para><guimenuitem>List of open files:</guimenuitem> you can choose the file to work on.</para></listitem>
<listitem><para><guimenuitem>Command window:</guimenuitem> this window permits simple operations on
the fields:</para><para>
for example: <literallayout>toto - 10*field + 36</literallayout></para>
<note>
<para>
In the default case, the name given to a field is of no importance.</para>
</note>
</listitem>
</itemizedlist>
</para>
</sect3>
<sect3 id="sect_calendar"><title>Calendar</title>
<para>
The calendar is made up of two droplists, which allow specification of
two dates, the beginning and end of a time series, or the period over
which to average before plotting.
</para>
</sect3>
<sect3 id="sect_domain"><title>Domain specification</title>
<para>
A series of widgets that allow specification of the min/max limits of
the domain in longitude/x-index, latitude/y-index, and depth in levels
or meters.  For depth, one can specify in levels for a horizontal
plot, and in meters for a vertical plot.
</para>
</sect3>
<sect3 id="details"><title>Plot details</title>
<para>
You can specify the min, max, and contour interval by filling out the
provided boxes! For the color palette, you can either specify the name
or go search for one among the palettes available.
</para>
<para>
The "keywords" window allows specification of all desired
keywords. These keywords can be those of
<filename>plt.pro</filename>, <filename>pltt.pro</filename>, <filename>pltz.pro</filename>,
<filename>plt1d.pro</filename>, or those of contour, plot, or all other programs that are
used. Cf <xref linkend="example1"/>
</para>
</sect3>
</sect2>
</sect1>
<sect1 id="examples"><title>Concrete examples of XXX in practice</title>

<sect2 id="example1"><title>First plots</title>

<para>
One single file, one single plot per page
</para>
<para>
Click on OK.
</para>
<para>
Test the various basic functions: change the dates, the zoom, the
field...</para>
<para>
Specify the min, max, and contour interval in the provided boxes.</para>
<para>
Add some keywords in the "keywords:" box, for example: </para>
<blockquote>
<para>
/nocontour, /carte
</para>
</blockquote>
<para>
or the keywords for a northern hortographic polar projection:</para>
<blockquote>
<para>
/nocontour, map=[90,0,0], /horto
</para>
</blockquote>
<para>
Test the various possibilities in the <guimenu>Save As</guimenu> menu.</para>
<note>
<para>
the creation of animations has a tendency to saturate the video
memory of X-terminals, crashing the entire program...</para>
</note>
<para>
Test the various possibilities in the <guimenu>Flag options</guimenu> menu.
</para>
<caution>
<para>
Careful, a selected option remains selected until it is reclicked.
</para>
</caution>
</sect2>

<sect2 id="example2"><title>Work with more than one file</title>
<para>
Open some other files and go between them by selecting them from the
file list...  Note that the different widgets (calendar, domain, ...)
follow the different file characteristics.
</para>
</sect2>

<sect2 id="mouse"><title>Mouse actions in the graphics window on a horizontal plot</title>

<para>
Select a domain and select the horizontal plot (<constant>plt</constant>), vertical plot
(<constant>pltz</constant>), or the hovmoeller plot (<constant>pltt</constant>):</para>
<para>
The domain we'd like to select for the plot is determined by one of
its diagonals, defined therefore by two points.  The first point is
defined when the mouse button is pushed, then the mouse is moved, and
the second point is defined as the mouse button is released
(click-drag).  The domains are thus defined by a long click (<abbrev>LC</abbrev>).  To
determine which type of plot should be made of selection, use:
<variablelist>
<varlistentry>
<term>
If the plot selector is on <constant>plt</constant>
</term>
<listitem>
<para>
the left mouse button to create horizontal plots (<constant>plt</constant>)</para>
<para>
the middle mouse button to create vertical plots (<constant>pltz</constant>)</para>
<para>
the right mouse button to create common hovmoellers for xt and yt cuts
(<constant>pltt</constant>)</para>
<para>
In summary: <abbrev>LCL</abbrev>---><constant>plt</constant></para>
<para>
LCM---><constant>pltz</constant></para>
<para>
LCR---><constant>pltt</constant></para>
</listitem>
</varlistentry>
<varlistentry>
<term>
If the plot selector is on something other than <constant>plt</constant>
</term>
<listitem>
<para>
the indicated plot type is made.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</sect2>
<sect2 id="multipleplots"><title>Create multiple plots on the same sheet and make them interact</title>

<para>
Select the number of columns and rows for the page.</para>
<para>
Create a first plot.  It will appear in the first frame.</para>
<para>
To create a plot in another frame double-click in the frame with the
middle button (<abbrev>DCM</abbrev>).  A black dotted frame will surround the
designated frame, the <quote>target</quote> frame.  A black frame will surround the
first plot.  This is the <quote>reference</quote> frame, in other words the one
that all the XXX widgets refer to.  Change for example the date and
create a new plot.  With a left button double-click in the first
frame, all the widgets change and refer again to the first plot.  A
double-click with the right button in the second frame will erase the
plot.</para>
<para>
In summary: <abbrev>DCL</abbrev>---><quote>reference</quote> frame</para>
<para>
<abbrev>DCM</abbrev>---><quote>target</quote> frame</para>
<para>
<abbrev>DCR</abbrev>--->erase the frame</para>
<para>
Here's a series of commands to show how this works.
</para>
<procedure>
<step>
<para>
Select a 3-D field and create 6 frames for the sheet of paper.
</para>
</step>
<step>
<para>
Create a horizontal plot in Frame 1
</para>
</step>
<!-- je n'arrive pas à utliser <stepalternatives> -->
<step>
<para>
<abbrev>DCM</abbrev> in frame 2, <abbrev>LCL</abbrev> on the plot in frame 1, to create a horizontal
zoom in frame 2.</para>
<para>
<abbrev>DCM</abbrev> in frame 3, <abbrev>LCM</abbrev> on the plot in frame 1, to create a vertical cut
in frame 3.</para>
<para>
<abbrev>DCM</abbrev> in frame 4, <abbrev>LCR</abbrev> on the plot in frame 1, to create a hovmoeller in frame 4.
</para>
</step>
</procedure>
<procedure>
<para>
To redo the hovmoeller with the keyword <literallayout>/nocontour</literallayout>
</para>
<step>
<para>
<abbrev>DCL</abbrev> in frame 4 which now becomes the reference and target frame.
</para>
</step>
<step>
<para>
Add the keyword
<literallayout>/nocontour</literallayout>
</para>
</step>
<step>
<para>
click <guibutton>OK</guibutton>, and the plot is redone.
</para>
</step>
</procedure>
<procedure>
<para>
in frame 5, let's create the same plot as in frame 2 except with different dates
</para>
<step>
<para>
<abbrev>DCL</abbrev> on frame 2
</para>
</step>
<step>
<para>
<abbrev>DCM</abbrev> on frame 5
</para>
</step>
<step>
<para>
change the date
</para>
</step>
<step>
<para>
click on <guibutton>OK</guibutton>
, and voilà, the new plot.
</para>
</step>
</procedure>
</sect2>
</sect1>
<sect1 id="crash"><title>How to quit when it crashes</title>

<para>
<orderedlist>
<listitem>
<para>
in the IDL window, type
  <screen format="linespecific">
<prompt>&promptidl;</prompt> <userinput>retall</userinput>
</screen>
</para></listitem>
<listitem>
<para><abbrev>DCR</abbrev> to erase the problem frame
</para>
</listitem>
<listitem><para>press the <guibutton>clear</guibutton> button
</para></listitem>
<listitem><para>change the orientation of the plot
</para></listitem>
<listitem><para>quit XXX cleanly using <guibutton>quit</guibutton> from the <guimenu>File</guimenu> menu
</para></listitem>
</orderedlist>
</para>
<note>
<para>
Always avoid if at all possible closing and killing the XXX
window, but rather select <guibutton>quit</guibutton> from the <guimenu>File</guimenu> menu.  XXX uses a
large number of pointers, and wantonly killing the window will leave a
large number of unused variables in memory, which could in the end
overflow.  To clean up this memory:
  <screen format="linespecific">
<prompt>&promptidl;</prompt> <userinput>ptr_free, ptr_valid()</userinput>
</screen>
</para>
</note>
</sect1>
</article>