# Welcome to the Highcharts Maps JS (highmaps) Options Reference

These pages outline the chart configuration options, and the methods and properties of Highcharts objects.

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# plotOptions.mapline.colorKey

Determines what data value should be used to calculate point color if `colorAxis` is used. Requires to set `min` and `max` if some custom point property is used or if approximation for data grouping is set to `'sum'`.