       document.getElementById("dropdownfilter").innerText="All Activities";
        }
        else {
            filterBy = Object.keys(icons)[value];
            document.getElementById("dropdownfilter").innerText=Object.values(icons)[value][1];
        }
        loadedTracks = new Set();
        geojsonfeatures = [];
        data = {
            "type": "FeatureCollection",
            "features": []};
        initData();
        map.getSource('activities').setData(data);

        map.getSource('tracks')