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

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

Feel free to search this API through the search bar or the navigation tree in the sidebar.

# series.mappoint.sonification.defaultSpeechOptions.pointGrouping.prop

The data property for each point to compare when deciding which points to keep in the group.

By default it is "y", which means that if the `"minmax"` algorithm is used, the two points the group with the lowest and highest `y` value will be kept, and the others not played.