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<h3><img alt="" src="../sun.gif" align="middle" height="98" width=
"100"> Binning</h3>
<blockquote>
<p>To create an image from a FITS Bin Table, the user needs to
specify a binning factor, binning buffer size, and the binning
function.<br></p>
<p>The Binning (or Block) Factor is defined as the following: A
value greater or equal to zero. This value indicates the number of
pixel values that will fall into a particular bin.<br></p>
<p>The Bin Buffer Size is overall size of the image generated. This
has no relation to min and max values of the columns used to create
the image.<br></p>
<p>The Bin Function is defined as the following: Average - all
pixel values that fall into one pixel bin are averaged. Sum - all
pixel values that fall into one pixel bin are summed.<br></p>
<p>Bin to Fit Frame will calculate a bin block factor as a power of
2 that will allow the entire data space to be displayed in the
current frame.</p>
<p>By default, DS9 will bin about the center of the image. To
determine the center of the image, DS9 will look for the following
keywords in order:</p>
<blockquote><tt>TDMIN/TDMAX<br>
TLMIN/TLMAX<br>
TALEN<br>
AXLEN</tt></blockquote>
<p>If no valid keywords are found, DS9 will define the center as
the middle of the possible data space based on the coordinate data
type.</p>
<br>
<p><br></p>
<p><br></p>
<br></blockquote>
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