mapp = {
const map = vl.markGeoshape({fill: '#ddd', stroke: '#fff', strokeWidth: 1})
.data(vl.topojson(usa).feature('states'));
const param = vl.param("sel_month")
.value(1)
.bind(vl.slider(1, 12, 1).name('Month: '))
const points = vl.markPoint(
{size: {expr: "datum.arr_flights * 2.3"}}
)
.data(sumData)
.transform(
vl.filter("datum.month == sel_month")
)
.encode(
vl.latitude().fieldQ('latitude'),
vl.longitude().fieldQ('longitude'),
vl.tooltip([vl.fieldN('Airport Code'), vl.fieldN('Airport Name'), vl.fieldQ('Percent Delayed (%)'), vl.fieldQ('Avg Daily Arrival Flights')]),
vl.fill().fieldQ('Percent Delayed (%)').scale({ scheme: "redyellowblue", reverse: true, domain: [0.0, 30.0]})
);
return vl.layer(map, points)
.project(vl.projection('albersUsa'))
.width(700).height(500)
.params(param)
.config({view: {stroke: null},header: {title: "hi"}})
.render()
}