{
let svg = d3.select(DOM.svg(width, height));
let g = svg.append("g");
let rodents = svg.append("g");
function handleMouseOver(d, i) {
d3.select(this).attr("fill", "orange");
}
function handleMouseOut(d, i) {
d3.select(this).attr("fill", "steelblue");
}
g.selectAll("path")
.data(nycBoroughs.features)
.enter()
.append("path")
.attr("fill", "#ccc")
.attr("stroke", "#333")
.attr("d", nycGeoPath);
rodents
.selectAll("path")
.data(treeGeoJSON)
.enter()
.append("path")
.attr("fill", "steelblue")
.attr("stroke", "none")
.attr("opacity", 0.5)
.attr("d", nycGeoPath)
.attr("class", "incident")
.on("click", (d) => d3.select("#label").text(d.properties.spc_common))
.on("mouseover", handleMouseOver)
.on("mouseout", handleMouseOut);
return svg.node();
}