{
const chas_0 = vl
.markPoint()
.data(housing)
.transform(vl.filter('datum["CHAS"]==1'))
.encode(
vl.y().fieldQ('Median House Price'),
vl.x().fieldQ('RM'),
vl
.color()
.fieldQ('DIS')
.scale({ scheme: 'blues' })
);
const chas_1 = vl
.markPoint()
.data(housing)
.transform(vl.filter('datum["CHAS"]==0'))
.encode(
vl.y().fieldQ('Median House Price'),
vl.x().fieldQ('RM'),
vl
.color()
.fieldQ('DIS')
.scale({ scheme: 'greens' })
);
return vl.hconcat(
vl.layer(chas_0, chas_0.markCircle()),
vl.layer(chas_1, chas_1.markCircle())
).render();
}