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<h2><b>grads | gradsdap <br>
gradsc | gradsnc | gradshdf | gradsdods</b> </h2>
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<td><p class="plaintext">GrADS is an interactive desktop tool for the analysis and
display of earth science data. GrADS is used worldwide and <a href="../downloads.html">freely
available</a> over the internet.
<p class="plaintext"> GrADS implements two data models: a 5-Dimensional gridded data model, and a station data model. In the gridded data model, the dimensions
are presumed to be latitude, longitude, level, time, and <a href="ensembles.html">ensemble</a>. In the station data model, data exist at arbitrary locations in space and time. Four dimensions (longitude, latitude, level, and time) are used as a framework in the station data model to guide which station reports are to be examined. Each data set is placed within
a 4- or 5-Dimensional space by the use of a data descriptor file. Both gridded
and station data may be described. Gridded data may be non-linearly spaced;
gaussian grids and variable resolution ocean model grids are directly supported.
The internal data format in a file may be binary, GRIB1, GRIB2, BUFR, NetCDF, HDF4-SDS, or HDF5.
<p class="plaintext"> Operations may be performed on the data directly, and interactively,
by entering expressions at the command line. The expression syntax allows complex
operations that range over very large amounts of data to be performed with simple
expressions. A rich set of built-in <a
href="functions.html">functions</a> are provided. In addition, users may add their
own functions as <a href="udf.html">external routines</a> written in any programming
language.
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<p class="plaintext">The syntax for running GrADS is:
<ul>
<p class="plaintext"><code><em>GrADS_executable </em><<i> options </i>></code></p>
</ul>
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<td colspan="2" bgcolor="e0f0ff">Beginning with GrADS version 2.0.a8, there is only one choice for <code><em>GrADS_executable, </em></code> a single, fully-featured build: </td>
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<td width="75" bgcolor="c5d5ff"><code>grads</code></td>
<td>Reads GRIB (version 1 and 2), gridded binary, BUFR, GrADS station
data, NetCDF (classic and NetCDF-4), HDF4-SDS, HDF5, and OPeNDAP (grids and station data)<br>
Writes binary, NetCDF (classic and NetCDF-4), GeoTIFF, KML<br>
Draws shapefiles</td>
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<td colspan="2" bgcolor="e0f0ff">For GrADS versions 2.0.a0 through 2.0.a7, the choices for <code><em>GrADS_executable</em></code> are: </td>
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<td width="75" bgcolor="c5d5ff"><code>grads</code></td>
<td>Reads GRIB (version 1 and 2), gridded binary, BUFR, GrADS station
data, NetCDF, HDF4-SDS<br>
Writes binary, NetCDF, (starting with 2.0.a5) GeoTIFF, KML</td>
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<td width="75" bgcolor="c5d5ff"><code>gradsdap</code></td>
<td>Reads GRIB (version 1 and 2), gridded binary, BUFR, GrADS station
data, NetCDF, HDF4-SDS, OPeNDAP <br>
Writes binary, NetCDF, (starting with 2.0.a5) GeoTIFF, KML</td>
</tr></table>
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<td colspan="2" bordercolor="#F4F4F4" bgcolor="#E0F0FF">For GrADS version 1.9 and earlier, the choices for <code><em>GrADS_executable</em></code> are: </td>
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<td width="100"><code>gradsc</code></td>
<td><span class="plaintext">Reads GRIB1, gridded binary, BUFR,
GrADS station data <br>
Writes binary, GRIB1</span></td>
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<td width="100"><code>gradsnc</code></td>
<td><span class="plaintext">Reads GRIB1, gridded binary, BUFR, GrADS station
data, NetCDF<br>
Writes binary, GRIB1, NetCDF</span></td>
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<td width="100"><code>gradshdf</code></td>
<td>
<p><span class="plaintext">Reads GRIB1, gridded binary, BUFR, GrADS station
data, NetCDF, HDF4-SDS<br>
Writes binary, GRIB1, HDF-SDS</span></p></td>
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<td width="100"><code>gradsdods</code></td>
<td><span class="plaintext">Reads GRIB1, gridded binary, BUFR, GrADS station
data, NetCDF, OPeNDAP (aka DODS) <br>
Writes binary, GRIB1, NetCDF</span></td>
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<td> </td>
<td> </td>
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<td colspan="2">Command line <code><i>options</i></code> are:</td>
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<td width="100"><code>-help</code></td>
<td>Prints the command line options.</td>
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<td><code>-a <em>ratio</em></code></td>
<td><p>(<span class="style1">GrADS 2.0.a9+</span>) Specifies the aspect ratio of the real page inside GrADS. A valid <code><em>ratio</em></code> is the X size divided by the Y size and must be greater than 0.2 and less than 5.0. Page size is scaled so the longer side will always be 11 inches. On startup, GrADS will provide the page dimensions with the message that begins with "<code>GX Package Initialization: Size = </code>"</p> </td>
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<td><code>-b</code></td>
<td>Runs GrADS in batch mode. No graphics output window is opened. </td>
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<td><code>-c <em>'command'</em></code></td>
<td>Executes the supplied <code><i>command</i></code> after GrADS has started. </td>
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<td><code>-C N</code></td>
<td>(<span class="style1">GrADS 2.0.a9+</span>) Enables colorization of text displayed in the GrADS command window. N can be 0, 1, or 2. If -C is invoked but N is not provided, color scheme 0 will be used. </td>
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<td><code>-E</code></td>
<td>Disables command line editing</td>
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<td><code>-g <em>geometry</em></code></td>
<td><p>Specifies the size of the graphics output window, which is a representation on your computer screen of the real page and may be any size at all. The size of the real page in GrADS is controlled by the -l or -p or -a options. The <code><em>geometry</em></code> argument has the syntax <code>W</code>x<code>H</code>+<code>X</code>+<code>Y</code> , where <code>W</code> is the width of window in pixels, <code>H</code> is the height of window in pixels, <code>X</code> is the starting pixel
point in x, and <code>Y</code> is the starting pixel point in y. Note that <code>X</code> and <code>Y</code> may be negative. </p></td>
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<td><code>-H <em>filename</em></code></td>
<td>Enables command line logging to <code><em>filename</em></code>. If <code><em>filename</em></code> is not provided, command history written to file $HOME/.grads.log</td>
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<td><code>-l</code></td>
<td>Runs GrADS in landscape mode, sets the "real" page size to 11 x 8.5. </td>
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<td><code>-m NNN</code></td>
<td>Sets metafile buffer size to NNN, which must be an integer. Default value
is 1000000.</td>
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<td><code>-p</code></td>
<td>Runs GrADS in portrait mode, sets the "real" page size to 8.5 x 11. <br>
If neither the <code>-l</code> or <code>-p</code> options are used, GrADS
will prompt the user for a preferred mode. </td>
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<td><code>-u</code></td>
<td>Unbuffers output, needed for IPC mode</td>
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<td width="100"><code>-x</code></td>
<td>Generally used with the -c option, causes GrADS to automatically quit
after the supplied <code><i>command</i></code> has been executed.</td>
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<p class="plaintext">Options that do not require arguments may be concatenated. Some examples follow: </p>
<p class="plaintext"><code> grads -pb <br>
grads -lbxc "myscript.gs" <br>
grads -Ca 1.7778 <br>
grads -C 2 -a 1.7778 <br>
grads -pHm 5000000 -g 1100x850+70+0 <br>
grads -pH mysession.log -m 5000000 -g 1100x850+70+0 </code>
<p>
<p>
<h2><a name="env"></a>Environment Variables </h2>
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<td colspan="2"><span class="plaintext">Some environment variables must be
set before starting the GrADS. </span></td>
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<td width="55"><span class="plaintext"><code>GADDIR</code> </span></td>
<td width="590"><span class="plaintext"> Points to the directory containing
the supplemental font and map files in the GrADS release package. If GADDIR is not set, GrADS will look in the default location, /usr/local/lib/grads/. </span></td>
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<td><span class="plaintext"><code>GASCRP</code> </span></td>
<td><span class="plaintext"> Points to a list of directories containing GrADS
utility scripts and user scripts. If more than one directory is specified, acceptable delimiters are a space, a semi-colon, colon, or a comma.</span></td>
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<td><code>GASHP</code></td>
<td>(<span class="style1">GrADS version 2.0.0+</span>) Points to a list of directories containing shapefiles. Put your shapefiles in those directories, and then it won't be necessary to use the full path when drawing or querying the shapefiles. If more than one directory is specified, acceptable delimiters are a space, a semi-colon, colon, or a comma.</td>
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<td><span class="plaintext"><code>GAUDFT</code> </span></td>
<td><span class="plaintext">Points to the user defined function table. If
this variable is not set, the function table will not be read.</span> </td>
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<p class="plaintext"> For example:
<p>
<span class="plaintext"><i>C-shell</i> </span>
<p> <span class="plaintext"><code>example% setenv GADDIR /ford1/local/lib/grads<br>
example% setenv GASHP $HOME/grads/shapefiles<br>
example% setenv GASCRP "$HOME/grads/scripts /opt/local/share/grads/library" <br>
example% setenv GAUDFT $HOME/grads/udf/table<br>
</code></span>
<p> <span class="plaintext"><i>Bourne shell</i></span>
<p> <span class="plaintext"><code>example% GADDIR=/ford1/local/lib/grads; export
GADDIR<br>
example% GASCRP=$HOME/grads/scripts; export GASCRP<br>
example% GAUDFT=$HOME/grads/udf/table; export GAUDFT<br>
</code></span>
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