Numeric Banding: Basic Options

Types of Banding

The ranges of the banding can be generated in a number of ways:

  • Equal Ranges: This creates ranges of equal size between the start and end values specified on the Advanced Options tab.

  • Geometric Ranges: This creates ranges of increasing size between the start and end values specified on the Advanced Options tab.

  • Quantile Ranges:  This creates ranges of varying size, defined so that each range contains an equal number of records as is possible.  The quantile ranges always cover the full range of values.

  •  User Defined Ranges: This allows the user to define their own ranges.  These must not overlap or have gaps.  However, they do not need to cover the full range of possible values.  

Bands Specified by

The bands can either be specified by number or by size.

Number of Bands

If a number of bands is specified then the size will be automatically determined so that the bands span the necessary range.  For example, if 10 bands are requested and the start and end values are 0 and 1000 respectively, Equal Ranges would create 10 bands of size 100.

If the size of bands is being automatically rounded, it is possible for the number of bands created to be less than that requested.  For example, if 10 bands are requested and the start and the end values are 0 and 890, the exact width of a band would be 89.  However, with automatic rounding this would be rounded up to 100, giving just 9 bands between 0 and 900.

Size of Bands

If the size of bands is specified then the number will be automatically determined so that the bands span the necessary range.  For example, if bands of size 200 are requested and the start and end values are 0 and 1000 respectively, Equal Ranges would create 5 bands of size 200.

For Quantiles it is only possible to specify the number of bands since the size varies.  For User Defined Ranges, the size and number are determined by the ranges typed in by the user.

On switching between Equal and Geometric Ranges, the Number of Bands option is automatically selected and the size of bands recalculated so as to achieve the same number of bands.

Base Selection

Setting the base selection limits all the analysis within the Numeric Banding tool to a subset of the full database.  This has a number of implications:

  • Only records within the base selection are counted towards the count of records falling within each range.  This will affect the height of the bars in the chart and the counts in the table view.

  • The automatically generated start and end values are determined by analyzing records within this base selection.  For example, specifying "Minimum Value" will set the start point of the bands to be the minimum value within the base selection.

  • All the statistics shown in the summary view are based on this base selection.