# 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.heatmap.shadow

Whether to apply a drop shadow to the graph line. Since 2.3 the shadow can be an object configuration containing `color`, `offsetX`, `offsetY`, `opacity` and `width`.

Note that in some cases, like stacked columns or other dense layouts, the series may cast shadows on each other. In that case, the `chart.seriesGroupShadow` allows applying a common drop shadow to the whole series group.