ch21s02.html
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Creating and formatting basic Windrose graphs</title><link rel="stylesheet" type="text/css" href="manual.css"><meta name="generator" content="DocBook XSL Stylesheets V1.76.0"><link rel="home" href="index.html" title="JpGraph Manual"><link rel="up" href="ch21.html" title="Chapter 21. Windrose"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Creating and formatting basic Windrose graphs</th></tr><tr><td width="20%" align="left"> </td><th width="60%" align="center">Chapter 21. Windrose</th><td width="20%" align="right"> </td></tr></table><hr></div><div class="sect1" title="Creating and formatting basic Windrose graphs"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2587220"></a>Creating and formatting basic Windrose graphs</h2></div></div></div>
<p>Creation of windrose graphs first requires the inclusion of the library extension
module "<code class="filename">jpgraph_windrose.php</code>"</p>
<p>The creation of Windrose graphs otherwise follows the traditional steps in the library
of creating a graph and then adding one or several windrose plots to the canvas.</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<p>Create a basic canvas graph as an instance of <code class="code">class
WindroseGraph</code></p>
</li><li class="listitem">
<p>Create an instance of one or several windrose plots as instances of
<code class="code">class WindrosePlot</code>, set up the scale and appearance and
then add them to the graph canvas.</p>
</li><li class="listitem">
<p>Send back the graph to the client with a call to
<code class="code">WindroseGraph::Stroke()</code>. As usual this can be used to
either send back the graph to the client (e.g.browser) or write the graph to
a file by specifying a filename as the first argument to
<code class="code">WindroseGraph::Stroke()</code>.</p>
</li></ol></div>
<p>The example in <a class="xref" href="ch21s02.html#fig.windrose_ex0" title="Figure 21.6. A basic 16 direction windrose graph (windrose_ex0.php)">Figure 21.6. A basic 16 direction windrose graph <code class="uri"><a class="uri" href="example_src/windrose_ex0.html" target="_top">(<code class="filename">windrose_ex0.php</code>)</a></code> </a> show a windrose graphs using
just the default values for all parameters. </p>
<p>
</p><div class="example"><a name="example.windrose_ex0"></a><p class="title"><b>Example 21.3. A basic 16 direction windrose graph (<code class="filename">windrose_ex0.php</code>) </b></p><div class="example-contents"> <div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
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</pre></td><td class="hl-main" valign="top"><pre><span class="hl-inlinetags"><?php</span><span class="hl-code">
</span><span class="hl-reserved">require_once</span><span class="hl-code"> </span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">jpgraph/jpgraph.php</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-reserved">require_once</span><span class="hl-code"> </span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">jpgraph/jpgraph_windrose.php</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-comment">//</span><span class="hl-comment"> Data can be specified using both ordinal index of the axis</span><span class="hl-comment"></span><span class="hl-code">
</span><span class="hl-comment">//</span><span class="hl-comment"> as well as the direction label</span><span class="hl-comment"></span><span class="hl-code">
</span><span class="hl-var">$data</span><span class="hl-code"> = </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-code">
</span><span class="hl-number">0</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">5</span><span class="hl-code">,</span><span class="hl-number">5</span><span class="hl-code">,</span><span class="hl-number">5</span><span class="hl-code">,</span><span class="hl-number">8</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-number">1</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">3</span><span class="hl-code">,</span><span class="hl-number">4</span><span class="hl-code">,</span><span class="hl-number">1</span><span class="hl-code">,</span><span class="hl-number">4</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-quotes">'</span><span class="hl-string">WSW</span><span class="hl-quotes">'</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">1</span><span class="hl-code">,</span><span class="hl-number">5</span><span class="hl-code">,</span><span class="hl-number">5</span><span class="hl-code">,</span><span class="hl-number">3</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-quotes">'</span><span class="hl-string">N</span><span class="hl-quotes">'</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">2</span><span class="hl-code">,</span><span class="hl-number">3</span><span class="hl-code">,</span><span class="hl-number">8</span><span class="hl-code">,</span><span class="hl-number">1</span><span class="hl-code">,</span><span class="hl-number">1</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-number">15</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">2</span><span class="hl-code">,</span><span class="hl-number">3</span><span class="hl-code">,</span><span class="hl-number">5</span><span class="hl-brackets">)</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-comment">//</span><span class="hl-comment"> First create a new windrose graph with a title</span><span class="hl-comment"></span><span class="hl-code">
</span><span class="hl-var">$graph</span><span class="hl-code"> = </span><span class="hl-reserved">new</span><span class="hl-code"> </span><span class="hl-identifier">WindroseGraph</span><span class="hl-brackets">(</span><span class="hl-number">400</span><span class="hl-code">,</span><span class="hl-number">400</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">Set</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">A basic Windrose graph</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-comment">//</span><span class="hl-comment"> Create the windrose plot.</span><span class="hl-comment"></span><span class="hl-code">
</span><span class="hl-var">$wp</span><span class="hl-code"> = </span><span class="hl-reserved">new</span><span class="hl-code"> </span><span class="hl-identifier">WindrosePlot</span><span class="hl-brackets">(</span><span class="hl-var">$data</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-comment">//</span><span class="hl-comment"> Add and send back to browser</span><span class="hl-comment"></span><span class="hl-code">
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">Add</span><span class="hl-brackets">(</span><span class="hl-var">$wp</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">Stroke</span><span class="hl-brackets">(</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-inlinetags">?></span></pre></td></tr></table></div></div></div><p><br class="example-break"> </p><div class="figure"><a name="fig.windrose_ex0"></a><p class="title"><b>Figure 21.6. A basic 16 direction windrose graph <code class="uri"><a class="uri" href="example_src/windrose_ex0.html" target="_top">(<code class="filename">windrose_ex0.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/windrose_ex0.png" alt="A basic 16 direction windrose graph (windrose_ex0.php)"></span> </div></div><p><br class="figure-break">
</p>
<p>In the same way as for other graph types one or several Windrose plots can be added
and positioned freely in the Windrose graph by specifying the position as either
absolute coordinates or as fractions of the width/height of the overall graph.</p>
<p>
</p><div class="tip" title="Tip" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Tip</h3>
<p>An easier way to position Windrose plots is to use layout classes as described
in <a class="xref" href="ch21s06.html" title="Using layout classes to position Windrose plots">Using layout classes to position Windrose plots</a></p>
</div><p>
</p>
<p>Each instance of the <code class="code">WindrosePlot</code> is added to the overall graph with a
call to the standard method </p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">WindroseGraph::Add($aObject)</code></p>
</li></ul></div><p>
</p>
<p>To avoid that all the plots collide in the middle the positioning and sizing methods
as shown in the previous sections should be used. </p>
<p>The following script shows how two plots are displayed in the same graph.</p>
<p>
</p><div class="example"><a name="example.windrose_2plots_ex1"></a><p class="title"><b>Example 21.4. Adding two windrose plots to the same graph (<code class="filename">windrose_2plots_ex1.php</code>) </b></p><div class="example-contents"> <div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
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</pre></td><td class="hl-main" valign="top"><pre><span class="hl-inlinetags"><?php</span><span class="hl-code">
</span><span class="hl-reserved">require_once</span><span class="hl-code"> </span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">jpgraph/jpgraph.php</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-reserved">require_once</span><span class="hl-code"> </span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">jpgraph/jpgraph_windrose.php</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-comment">//</span><span class="hl-comment"> Data can be specified using both ordinal idex of axis as well</span><span class="hl-comment"></span><span class="hl-code">
</span><span class="hl-comment">//</span><span class="hl-comment"> as the direction label</span><span class="hl-comment"></span><span class="hl-code">
</span><span class="hl-var">$data</span><span class="hl-code"> = </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-code">
</span><span class="hl-number">1</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">10</span><span class="hl-code">,</span><span class="hl-number">10</span><span class="hl-code">,</span><span class="hl-number">13</span><span class="hl-code">,</span><span class="hl-number">7</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-number">2</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">2</span><span class="hl-code">,</span><span class="hl-number">8</span><span class="hl-code">,</span><span class="hl-number">10</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-number">4</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">1</span><span class="hl-code">,</span><span class="hl-number">12</span><span class="hl-code">,</span><span class="hl-number">22</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$data2</span><span class="hl-code"> = </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-code">
</span><span class="hl-number">4</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">12</span><span class="hl-code">,</span><span class="hl-number">8</span><span class="hl-code">,</span><span class="hl-number">2</span><span class="hl-code">,</span><span class="hl-number">3</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-number">2</span><span class="hl-code"> => </span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">5</span><span class="hl-code">,</span><span class="hl-number">4</span><span class="hl-code">,</span><span class="hl-number">4</span><span class="hl-code">,</span><span class="hl-number">5</span><span class="hl-code">,</span><span class="hl-number">2</span><span class="hl-brackets">)</span><span class="hl-code">,
</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-comment">//</span><span class="hl-comment"> Create a new small windrose graph</span><span class="hl-comment"></span><span class="hl-code">
</span><span class="hl-var">$graph</span><span class="hl-code"> = </span><span class="hl-reserved">new</span><span class="hl-code"> </span><span class="hl-identifier">WindroseGraph</span><span class="hl-brackets">(</span><span class="hl-number">660</span><span class="hl-code">,</span><span class="hl-number">400</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">SetShadow</span><span class="hl-brackets">(</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">Set</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">Two windrose plots in one graph</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">SetFont</span><span class="hl-brackets">(</span><span class="hl-identifier">FF_ARIAL</span><span class="hl-code">,</span><span class="hl-identifier">FS_BOLD</span><span class="hl-code">,</span><span class="hl-number">14</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">subtitle</span><span class="hl-code">-></span><span class="hl-identifier">Set</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">(Using Box() for each plot)</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp</span><span class="hl-code"> = </span><span class="hl-reserved">new</span><span class="hl-code"> </span><span class="hl-identifier">WindrosePlot</span><span class="hl-brackets">(</span><span class="hl-var">$data</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp</span><span class="hl-code">-></span><span class="hl-identifier">SetType</span><span class="hl-brackets">(</span><span class="hl-identifier">WINDROSE_TYPE8</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp</span><span class="hl-code">-></span><span class="hl-identifier">SetSize</span><span class="hl-brackets">(</span><span class="hl-number">0</span><span class="hl-number">.42</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp</span><span class="hl-code">-></span><span class="hl-identifier">SetPos</span><span class="hl-brackets">(</span><span class="hl-number">0</span><span class="hl-number">.25</span><span class="hl-code">,</span><span class="hl-number">0</span><span class="hl-number">.55</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp</span><span class="hl-code">-></span><span class="hl-identifier">SetBox</span><span class="hl-brackets">(</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp2</span><span class="hl-code"> = </span><span class="hl-reserved">new</span><span class="hl-code"> </span><span class="hl-identifier">WindrosePlot</span><span class="hl-brackets">(</span><span class="hl-var">$data2</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp2</span><span class="hl-code">-></span><span class="hl-identifier">SetType</span><span class="hl-brackets">(</span><span class="hl-identifier">WINDROSE_TYPE16</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp2</span><span class="hl-code">-></span><span class="hl-identifier">SetSize</span><span class="hl-brackets">(</span><span class="hl-number">0</span><span class="hl-number">.42</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp2</span><span class="hl-code">-></span><span class="hl-identifier">SetPos</span><span class="hl-brackets">(</span><span class="hl-number">0</span><span class="hl-number">.74</span><span class="hl-code">,</span><span class="hl-number">0</span><span class="hl-number">.55</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp2</span><span class="hl-code">-></span><span class="hl-identifier">SetBox</span><span class="hl-brackets">(</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$wp2</span><span class="hl-code">-></span><span class="hl-identifier">SetRangeColors</span><span class="hl-brackets">(</span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">green</span><span class="hl-quotes">'</span><span class="hl-code">,</span><span class="hl-quotes">'</span><span class="hl-string">yellow</span><span class="hl-quotes">'</span><span class="hl-code">,</span><span class="hl-quotes">'</span><span class="hl-string">red</span><span class="hl-quotes">'</span><span class="hl-code">,</span><span class="hl-quotes">'</span><span class="hl-string">brown</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">Add</span><span class="hl-brackets">(</span><span class="hl-var">$wp</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">Add</span><span class="hl-brackets">(</span><span class="hl-var">$wp2</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">Stroke</span><span class="hl-brackets">(</span><span class="hl-brackets">)</span><span class="hl-code">;
</span><span class="hl-inlinetags">?></span></pre></td></tr></table></div></div></div><p><br class="example-break"> </p><div class="figure"><a name="fig.windrose_2plots_ex1"></a><p class="title"><b>Figure 21.7. Adding two windrose plots to the same graph <code class="uri"><a class="uri" href="example_src/windrose_2plots_ex1.html" target="_top">(<code class="filename">windrose_2plots_ex1.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/windrose_2plots_ex1.png" alt="Adding two windrose plots to the same graph (windrose_2plots_ex1.php)"></span> </div></div><p><br class="figure-break">
</p>
<div class="sect2" title="Specifying the windrose scale"><div class="titlepage"><div><div><h3 class="title"><a name="id2587433"></a>Specifying the windrose scale</h3></div></div></div>
<p>The scale is a property of each plot and is access though the instance variable
<code class="code">WindrosePlot::scale</code>. The scale consists of the epi-centric circles
that radiates from the center of the Windrose plot. The step between each circle can
be set manually or it can be done automatically by the library depending on the data
values. </p>
<p>(In order to keep the flow of the text this section leaves the full examples to
the example section.)</p>
<p>To manual set the scale of the circles the following method is used:</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">WindrosePlotScale::SetStepSize($aMax,$aStepSize=null)</code></p>
<p><code class="code">$aMax</code>, The maximum scale value</p>
<p><code class="code">$aStepSize</code>, The step between each scale circle</p>
</li></ul></div><p>
</p>
<p>By default the library tries multiple of 5:s and 2:s for a visually esthetic grid
spacing. </p>
<p>Other example of methods available to adjust the scale are</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">WindrosePlotScale::SetFont($aFontFamily,$aFontStyle=FS_NORMAL,$aFontSize=10)</code></p>
<p>Specify font for all scale labels apart from the 0-label (in the
center)</p>
</li><li class="listitem">
<p><code class="code">WindrosePlotScale::SetZFont($aFontFamily,$aFontStyle=FS_NORMAL,$aFontSize=10)</code></p>
<p>Specify the font for the 0-label (in the center)</p>
</li><li class="listitem">
<p><code class="code">WindrosePlotScale::SetFontColor($aColor)</code></p>
<p>Specify font color for all scale labels apart from the 0-label (in the
center)</p>
</li><li class="listitem">
<p><code class="code">WindrosePlotScale::SetZFontColor($aColor)</code></p>
<p>Specify the font for the 0-label (in the center)</p>
</li><li class="listitem">
<p><code class="code">WindrosePlotScale::SetLabelFillColor($aBkgColor,$aBorderColor=false)</code></p>
<p>Set the background color for the labels</p>
</li><li class="listitem">
<p><code class="code">WindrosePlotScale::SetLabelAlign($aAlign)</code></p>
<p>Set the label text alignment</p>
</li><li class="listitem">
<p><code class="code">WindrosePlotScale::SetLabelFormat($aFmt)</code></p>
<p>Set the label format. This is specified as a "<code class="code">printf()</code>"
format string.</p>
</li><li class="listitem">
<p><code class="code">WindrosePlotScale::Hide($aFlg)</code></p>
<p>Hide the scale labels</p>
</li></ul></div><p>
</p>
<p>Examples of how to use these methods are shown in the following sections.</p>
<div class="sect3" title="Specifying fonts and font colors"><div class="titlepage"><div><div><h4 class="title"><a name="id2587654"></a>Specifying fonts and font colors</h4></div></div></div>
<p>Fonts can be specified for both the labels on the scale as well as separately
for the label in the center of the plot. The following code snippet shows how to
do this (we assume we have already created a windrose plot called
"<code class="code">windplot</code>") </p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
3
4
5
6
7
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">// Font and color for scale labels
$windplot->scale->SetFont(FF_VERDANA,FS_NORMAL,10);
$windplot->scale->SetFontColor('navy');
// Font and color for the center (Zero circle) label
$windplot->scale->SetZFont(FF_VERDANA,FS_NORMAL,10);
$windplot->scale->SetZFontColor('navy');</span></pre></td></tr></table></div><p>
</p>
</div>
<div class="sect3" title="Manually specifying the scale"><div class="titlepage"><div><div><h4 class="title"><a name="id2587682"></a>Manually specifying the scale</h4></div></div></div>
<p>By default the library automatically determines a scale range and step size
taking into account the maximum value of data, size of the plot and the font
size specified for the scale labels. </p>
<p>However it is possible to force a manual scale and step size with a call to
<code class="code">Set($aMaxValue,$aStepSize)</code>. This call sets the maximum scale
value as well as the step size. The step size is optional. If the step size is
not specified it will be automatically determined. </p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
3
4
5
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">// Specify both maximum value and a step size
$windplot->scale->Set(40,8);
...
// Specify just the maximum value
$windplot->scale->Set(40);</span></pre></td></tr></table></div><p>
</p>
<p>This feature is also illustrated in <a class="xref" href="ch21s07.html#fig.windrose_ex7" title="Figure 21.25. (windrose_ex7.php)">Figure 21.25. <code class="uri"><a class="uri" href="example_src/windrose_ex7.html" target="_top">(<code class="filename">windrose_ex7.php</code>)</a></code> </a> in
the example part of this chapter.</p>
<p>
</p><div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>The automatic scaling tries to first use step sizes as multiples of 5
and then multiples of 2 to achieve a suitable spacing of the scale
lines.</p>
</div><p>
</p>
<p>
</p><div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>It might be surprising to see that the scale steps may change when the
label font is changed. However, this is by design. The reason for this
is that there is only a certain amount of space available for the labels
between each step. In order for large fonts to fit the space between the
grids the step between each circle must be large enough.</p>
</div><p>
</p>
</div>
<div class="sect3" title="Specifying the label angle"><div class="titlepage"><div><div><h4 class="title"><a name="id2587738"></a>Specifying the label angle</h4></div></div></div>
<p>The labels for the scale is placed along a line radiating from the center of
the windrose plots. The angle for the labels can be either manually or
automatically determined. </p>
<p>The labels for the scale is placed along one of the sixteen compass directions
if you choose automatic positioning of the labels. By default the library tries
to choose a direction with as little data around it as possible.</p>
<p>To manually specify the angle a call to <code class="code">SetAngle($aAngle)</code> with
the angle (in degrees) as argument. </p>
<p>The code snippet below shows how to do this </p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">// Show the labels at 45 degrees angle
$windplot->scale->SetAngle(45);</span></pre></td></tr></table></div><p>
</p>
<p>To specify that the library should do this automatically (which is the
default) the angle is specified as the string 'auto' as</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">// Let the library determine a good angle
$windplot->scale->SetAngle('auto');</span></pre></td></tr></table></div><p>
</p>
</div>
<div class="sect3" title="Specifying number formats for scale labels"><div class="titlepage"><div><div><h4 class="title"><a name="id2587797"></a>Specifying number formats for scale labels</h4></div></div></div>
<p>In the same way as for other scales in the library it is possible to specify a
"printf()" format string to adjust the appearance of the labels. By default the
label format is the same as</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$windplot->scale->SetLabelFormat('%d%%');</span></pre></td></tr></table></div><p>
</p>
</div>
</div>
<div class="sect2" title="Specifying direction labels"><div class="titlepage"><div><div><h3 class="title"><a name="id2587804"></a>Specifying direction labels</h3></div></div></div>
<p>With direction labels we mean the names of the compass directions surrounding the
windrose plot. By default they are given the English short form for the 16 discrete
compass named directions. This can also be localized (described in ??).</p>
<div class="sect3" title="Specifying fonts and font colors for the axis titles (direction labels)"><div class="titlepage"><div><div><h4 class="title"><a name="id2587835"></a>Specifying fonts and font colors for the axis titles (direction
labels)</h4></div></div></div>
<p>Fonts for the axis titles are specified with (with the usual arguments)</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">WindrosePlot::SetFont()</code></p>
</li><li class="listitem">
<p><code class="code">WindrosePlot::SetFontColor()</code></p>
</li></ul></div><p>as the following example shows </p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$windplot->SetFont(FF_TIMES,FS_BOLD,12);
$windplot->SetFontColor('darkgreen');</span></pre></td></tr></table></div><p>
</p>
<p>Which for example could give a Windrose plot as shown in <a class="xref" href="ch21s07.html#fig.windrose_ex4" title="Figure 21.22. (windrose_ex4.php)">Figure 21.22. <code class="uri"><a class="uri" href="example_src/windrose_ex4.html" target="_top">(<code class="filename">windrose_ex4.php</code>)</a></code> </a></p>
</div>
<div class="sect3" title="Setting arbitrary text for data directions"><div class="titlepage"><div><div><h4 class="title"><a name="id2587887"></a>Setting arbitrary text for data directions</h4></div></div></div>
<p>Wen using the free direction windrose plots the default label is the direction
for the data in degrees. This is fully customizable by using the following
method. </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">WindrosePlot::SetLabels($aLabels)</code></p>
<p>The input data to this method is an associative array where the
keys are the direction and the content is the text to be
displayed.</p>
</li></ul></div>
<p>Please note that for regular Windrose plots, i.e. with only compass direction
the label can not be changed. This is only available if the type of the windrose
plot is <code class="code">WINDROSE_TYPEFREE</code>.</p>
<p>The following example specifies a data point at 50 degrees and a text
"Point\n#7315" as the label.</p>
<p>
</p><div class="tip" title="Tip" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Tip</h3>
<p>Labels can contain "\n" which will be interpreted as a line break.
</p>
</div><p>
</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
3
4
5
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$data = array( 50 => array(12,12,2) );
$labels = array( 50 => 'Point #7315' );
...
$windplot = new WindrosePlot();
$windplot->SetLabels($labels);</span></pre></td></tr></table></div><p>
</p>
<p>An example of this can be seen in <a class="xref" href="ch21s07.html#fig.windrose_ex6" title="Figure 21.24. (windrose_ex6.php)">Figure 21.24. <code class="uri"><a class="uri" href="example_src/windrose_ex6.html" target="_top">(<code class="filename">windrose_ex6.php</code>)</a></code> </a></p>
</div>
<div class="sect3" title="Adjusting the alignment and margin"><div class="titlepage"><div><div><h4 class="title"><a name="id2587959"></a>Adjusting the alignment and margin</h4></div></div></div>
<p>There are two basic ways of adjusting the position of the compass labels
around the plot: </p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p>Adjusting the margin between the label and the outer plot
circle</p>
</li><li class="listitem">
<p>Adjusting the anchor point of the labels.</p>
</li></ul></div><p>
</p>
<p>The easiest way to explain this is to first imagine an invisible circle around
the plot. The margins specifies how far from the outer scale circle this
imaginative circle is placed. </p>
<p>In order to position the labels on that circle around the plot there are
several possible ways to select what point of the text should be positioned on
the circle. The easiest way is to select the center (both in X and Y directions)
of the text. This works well if all labels are roughly the same size. If there
are big difference between the smallest and largest label it might be necessary
to have a very large margin to avoid the text to "collide" with the plot.</p>
<p>A better way is to determine the closest point of the text to the plot and
then make that point lay on the circle. The closets point depends on what
compass direction the label is on, for example for the "East" label the closes
point is the middle of the left side of the text and for the "West" the closes
point is the middle of the right side.</p>
<p>The library supports both way of positioning through the method </p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">WindrosePlot::SetLabelPosition($aPosition)</code></p>
<p>Valid values for $aPosition are <code class="code">LBLPOSIITON_CENTER</code>
and <code class="code">LBLPOSITION_EDGE</code> .</p>
</li></ul></div><p>The following code snippet shows how to specify both margin and
position do this: </p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$windplot->SetLabelMargin(30);
$windplot->SetLabelPosition(LBLPOSITION_EDGE);</span></pre></td></tr></table></div><p>
</p>
<p>The red circle in ?? and ?? illustrates the "imaginative" circle on which the
labels are placed. The distance from the out most plot circle to the label
anchor point is the margin.</p>
<table xmlns="" frame="void" id="id2588065">
<tbody xmlns="">
<tr>
<td>
<div class="figure"><a name="id2588081"></a><p class="title"><b>Figure 21.8. Positioning with LBLPOSITION_CENTER</b></p><div class="figure-contents">
<div class="mediaobject"><img src="images/windrose_label-align1.png" alt="Positioning with LBLPOSITION_CENTER"></div>
</div></div><br class="figure-break">
</td>
<td>
<div class="figure"><a name="id2588101"></a><p class="title"><b>Figure 21.9. Positioning with LBLPOSITION_EDGE</b></p><div class="figure-contents">
<div class="mediaobject"><img src="images/windrose_label-align2.png" alt="Positioning with LBLPOSITION_EDGE"></div>
</div></div><br class="figure-break">
</td>
</tr>
</tbody>
</table>
<p>An example of this can be seen in <a class="xref" href="ch21s07.html#fig.windrose_ex6" title="Figure 21.24. (windrose_ex6.php)">Figure 21.24. <code class="uri"><a class="uri" href="example_src/windrose_ex6.html" target="_top">(<code class="filename">windrose_ex6.php</code>)</a></code> </a></p>
</div>
</div>
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