我想把这个地球仪的大小设置为200 x 200像素。
我知道目前这个投影的大小是960 x 500像素。
改变SVG的大小并不能缩小地球仪。我不太明白为什么。
尝试在代码中添加以下内容,但没有成功:
var width = 200;
var height = 200;
并且
const width = 200;
const height = 200;
并且
const svg = d3.select('svg')
.attr('width', 200).attr('height', 200);
我应该如何最好地解决这个问题,我做错了什么?
我的代码:
<!DOCTYPE html>
<html>
<body>
<svg></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v1.min.js"></script>
<script>
const width = 960;
const height = 500;
const config = {
speed: 0.005,
verticalTilt: -20,
horizontalTilt: 0
}
let locations = [];
const svg = d3.select('svg')
.attr('width', width).attr('height', height);
const markerGroup = svg.append('g');
const projection = d3.geoOrthographic();
const initialScale = projection.scale();
const path = d3.geoPath().projection(projection);
const center = [width/2, height/2];
drawGlobe();
drawGraticule();
enableRotation();
function drawGlobe() {
d3.queue()
.defer(d3.json, 'world-110m.json')
.defer(d3.json, 'locations.json')
.await((error, worldData, locationData) => {
svg.selectAll(".segment")
.data(topojson.feature(worldData, worldData.objects.countries).features)
.enter().append("path")
.attr("class", "segment")
.attr("d", path)
.style("stroke", "silver")
.style("stroke-width", "1px")
.style("fill", (d, i) => 'silver')
.style("opacity", ".5");
locations = locationData;
drawMarkers();
});
}
function drawGraticule() {
const graticule = d3.geoGraticule()
.step([10, 10]);
svg.append("path")
.datum(graticule)
.attr("class", "graticule")
.attr("d", path)
.style("fill", "#fff")
.style("stroke", "#ececec");
}
function enableRotation() {
d3.timer(function (elapsed) {
projection.rotate([config.speed * elapsed - 120, config.verticalTilt, config.horizontalTilt]);
svg.selectAll("path").attr("d", path);
drawMarkers();
});
}
function drawMarkers() {
const markers = markerGroup.selectAll('circle')
.data(locations);
markers
.enter()
.append('circle')
.merge(markers)
.attr('cx', d => projection([d.longitude, d.latitude])[0])
.attr('cy', d => projection([d.longitude, d.latitude])[1])
.attr('fill', d => {
const coordinate = [d.longitude, d.latitude];
gdistance = d3.geoDistance(coordinate, projection.invert(center));
return gdistance > 1.57 ? 'none' : 'tomato';
})
.attr('r', 7);
markerGroup.each(function () {
this.parentNode.appendChild(this);
});
}
</script>
</body>
</html>