Data-driven symbol icons This sample shows how to use multiple custom icons in a single symbol layer by using data-driven styling with an expression. This sample uses a GeoJSON file that contains points of interest as a data source. Each record in this data set has an EntityType property which is one of the following properties: 'Gas Station', 'Grocery Store', 'Restaurant', 'School'. This sample uses the EntityType property to select the icon to display on the map.