getPetalColor = value => {
if (scheme == 'yellow-orange') {
const scale = d3.scaleLinear().range([0.4, 0.6]);
return d3.interpolateYlOrBr(scale(value));
} else if (scheme == 'red-yellow') {
const scale = d3.scaleLinear().range([0.2, 0.3]);
return d3.interpolateRdYlGn(scale(value));
} else if (scheme == 'purple') {
const scale = d3.scaleLinear().range([0.6, 0.7]);
return d3.interpolatePurples(scale(value));
}
}