Bin

### Binning

> To create an image from a FITS Bin Table, the user needs to specify a binning factor, binning buffer size, and the binning function.

> 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.

> 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.

> 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.

> 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.

> 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:

> > `TDMIN/TDMAX
> > TLMIN/TLMAX
> > TALEN
> > AXLEN`

> 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.