choromap = vl.markGeoshape({stroke: '#aaa', strokeWidth: 0.25})
.data(vl.topojson(usa).feature('counties'))
.transform(
vl.lookup('id').from(vl.data(unemployment).key('id').fields('rate'))
)
.encode(
vl.color().fieldQ('rate').scale({domain: [0.01,0.19],clamp:true, typw:'quantize',scheme:{name:'yellowgreenblue',count:9}}).legend({format:'%',title:'Taxa'}),
vl.tooltip().fieldQ('rate').format('.0%')
)
.project(vl.projection('albersUsa'))
.width(890).height(500)
.render()