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  28  <H3><A NAME="7_1_8">7.1.8 Using logarithmic scale</A></H3>
  29  <P> Using a logarithmic scale requires you to include the logarithmic
  30   add on module in &quot;jpgraph_log.php&quot;. So you must have the line<DIV class="phpscript">
  31  <CODE><FONT color="#000000"> <FONT color="#0000BB">&nbsp;</FONT><FONT color="#007700">
  32  include(</FONT><FONT color="#DD0000">&quot;jpgraph_log.php&quot;</FONT><FONT color="#007700">
  33  );</FONT><FONT color="#0000BB"></FONT></FONT></CODE></DIV></P>
  34  <P>on the top of your code. To Illustrate how to use a logarithmic scale
  35   let's make the right Y scale in the previous example a logarithmic
  36   scale. This is done by the line<DIV class="phpscript"><CODE><FONT color="#000000">
  37   <FONT color="#0000BB">&nbsp;$graph</FONT><FONT color="#007700">-&gt;</FONT><FONT
  38  color="#0000BB">SetY2Scale</FONT><FONT color="#007700">(</FONT><FONT color="#DD0000">
  39  &quot;log&quot;</FONT><FONT color="#007700">);</FONT><FONT color="#0000BB"></FONT></FONT>
  40  </CODE></DIV></P>
  41  <P>This will then give the following result<DIV class="example">
  42  <BR> <A href="exframes/frame_example7.html" target="blank"><IMG border="0"
  43  HEIGHT="200"       src="img/img/img/img/img/img/example7.png" WIDTH="350"></A>
  44  <BR><B>Figure 17:</B> Using a logarithmic scale for both the Y2 axis <A href="exframes/frame_example7.html"
  45  target="blank">[src]</A>&nbsp;
  46  <P></P>
  47  </DIV></P>
  48  <P></P>
  49  <P> You can of course also use a logarithmic X-scale as well. The
  50   following example shows this.<DIV class="example">
  51  <BR> <A href="exframes/frame_loglogex1.html" target="blank"><IMG border="0"
  52  HEIGHT="300"       src="img/img/img/img/img/img/loglogex1.png" WIDTH="500"></A>
  53  <BR><B>Figure 18:</B> Example of using log scale on both X and Y axis
  54   together with a linear Y2 scale <A href="exframes/frame_loglogex1.html" target="blank">
  55  [src]</A>&nbsp;
  56  <P></P>
  57  </DIV></P>
  58  <P> Even though we have so far only shown line graphs logarithmic scale
  59   can also be used for bar, error, scatter plots as well. Even radar
  60   plots supports the use of logarithmic plots. The following example
  61   shows how to use a logarithmic scale for a bar graph.</P>
  62  <P><DIV class="example">
  63  <BR> <A href="exframes/frame_logbarex1.html" target="blank"><IMG border="0"
  64  HEIGHT="220"       src="img/img/img/img/img/img/logbarex1.png" WIDTH="400"></A>
  65  <BR><B>Figure 19:</B> Example of using logarithmic scale togther with
  66   bar plots <A href="exframes/frame_logbarex1.html" target="blank">[src]</A>
  67  &nbsp;
  68  <P></P>
  69  </DIV></P>
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