new SizeFormatter()
Creates a new style Formatter that returns a proper size value for
any given data value.
The options parameter is a JSON object containing several optional
properties, such as:
- scale the scale used to format or classify data values. If not specified, the default logarithm scale is used.
- numClasses the number of classes or buckets to use.
- startingSize The minimum or starting size; for any computed size, if it's smaller than this value, then use this instead.
- delta the delta in size between any two adjacent classes
- defaultSize the default size to use when the data value is null or a proper color cannot be determined. This color is typically used to render shapes with no data. Default is 0 (which means the marker will not be displayed).
- style the (Marker) style which this formatter is applied to. Optional.
- lengthUnit {String} the unit of the size, value can be "pixel" or "kilometer"; the default unit is pixel