Question

我有一张世界地图，将被放入popovers / modals（following this tutorial）使用时，需要放大到给定的国家/地区。我制作了一张参考地图，隐藏了它，复制了它的内容，创建了一个新的（本地化的）地图。问题是：我无法在新地图上更新projection.scale。它适用于原始地图，遵循this answer的说明。

我是第一次来这里寻求帮助。非常感谢。我确定这不是最好的做法，但是重新绘制一个新的svg的负载时间是一次性能损失。

var width = 280, height = width/2, scale = 50;
var projection, path, svg, g, countries, country, content;

projection = d3.geo.mercator()
  .translate([(width/2), (height/2)])
  .scale( width / 2 / Math.PI);
path = d3.geo.path().projection(projection);

svg = d3.select("#referenceMap").append("svg")
  .attr("width", width)
  .attr("height", height);
g = svg.append("g");

d3.json("data/world-topo-min.json", function(error, world) {
  countries = topojson.feature(world, world.objects.countries).features;
  country = g.selectAll(".country").data(topo);
  country.enter().insert("path")
    .attr("class", "country")
    .attr("d", path)
    .attr("id", function(d,i) { return d.id; })
    .attr("title", function(d,i) { return d.properties.name; })
    .style("fill", function(d, i) { return d.properties.color; });

  content = d3.select('#referenceMap').html(); // -- copy the SVG
});

function copyMap(element, countryName) {
  var countryPath = countries.filter(function(d) {
    return d.properties.name == countryName;
  })[0];

  var div = d3.select(element).html(content); // -- 'paste' the SVG
  g = d3.select(element).select('g');
    .attr("fill", 'rgb(102, 106, 79)'); // -- this works fine as well

  // Issue Area: Update the projection to pan and zoom on the given country 
  var bounds  = path.bounds(countryPath);
  var hscale  = scale*width  / (bounds[1][0] - bounds[0][0]);
  var vscale  = scale*height / (bounds[1][1] - bounds[0][1]);
  scale   = (hscale < vscale) ? hscale : vscale;
  var offset  = [width - (bounds[0][0] + bounds[1][0])/2,
                    height - (bounds[0][1] + bounds[1][1])/2];

  // new projection
  projection = d3.geo.mercator().center(d3.geo.centroid(countryPath))
    .scale(scale).translate(offset);
  path = path.projection(projection);
}

Answer 1

做projection.scale（600）之后;我需要添加g.selectAll（＆＃34; path＆＃34;）。attr（＆＃34; d＆＃34;，path）;.不幸的是，这只会使我的popover的加载速度保持太长。

// new projection
projection = d3.geo.mercator().center(d3.geo.centroid(countryPath))
.scale(scale).translate(offset);
path = path.projection(projection);
g.selectAll("path").attr("d", path); // <-- Added this line to fix the issue.

如何在复制d3，svg地图后更新投影

1 个答案: