Question

我正在研究世界交互式地图（缩放+拖动）上的Orthogonal和Mercator投影之间的过渡。我的尝试是基于this answer @mbostock。我的过渡效果很好，但控制台会返回：

错误：属性d =＆＃34的值无效; M399.97994119370463,631.2543931983346L401.90905516286807,634.6157013775801L402.49382423943246,639.8924592362391L397.1999166487309，.......， InfinityL492，InfinityL298.23496934976544 ，InfinityZ ＆＃34;

也

错误：属性d的值无效=＆＃34; M407.5277462873383,448.4656515493841L407.3237573717514,448.5198670656254L408.0599991645186,448.54332648718287L408.0215749188842,448.4385574971469ZM410.40575858016456,448.5990104765492L410.8017911794915,448.571665201377L411.4470970198755 .. 。，NaNL415，NaNL415，的 NaNZM415，NaNL415，NaNL415，NaNZM415，NaNL415 下，449.0295187376797L415,449.0295187376797L414.9999381778805,449.02952802059315L415,449.02952802059315L414.41200773961845，..＆＃34;

我正在使用Natural Earth shapefile中的topoJson，每次返回补间函数时，我只会收到其中一个路径错误。我相信这意味着只有一个路径元素出现此问题。

以下是我在投影类中的转换方法：

animation(timeout, newProjection) {
  let self = this;
  let projection = this.interpolatedProjection(this.prjFnc, newProjection);
  let path = d3.geo.path().projection(projection);
  this.svg.transition()
    .duration(timeout / 2)
    .tween('projection', function() {
      return function(_) {
        self.alpha(_);
        self.svg.selectAll('path').attr('d', path);
      };
    });
}
interpolatedProjection(a, b) {
  let self = this;
  this.a = a;
  this.b = b;
  this.α = null;
  function raw(λ, φ) {
    let pa = self.a([λ *= 180 / Math.PI, φ *= 180 / Math.PI]), pb = self.b([λ, φ]);
    return [(1 - self.α) * pa[0] + self.α * pb[0], (self.α - 1) * pa[1] - self.α * pb[1]];
  }
  this.intProjection = d3.geo.projection(raw).scale(1);
  this.center = this.intProjection.center;
  this.translate = this.intProjection.translate;
  delete this.intProjection.scale;
  delete this.intProjection.translate;
  delete this.intProjection.center;
  return this.alpha(0.1);
}
alpha(_) {
  if(!arguments.length) {
    return this.α;
  }
  this.α = +_;
  let ca = this.a.center(),
      cb = this.b.center(),
      ta = this.a.translate(),
      tb = this.b.translate();

  this.center(
    [(1 - this.α) * ca[0] + this.α * cb[0],
    (1 - this.α) * ca[1] + this.α * cb[1]]
  );
  this.translate(
    [Math.round((1 - this.α) * ta[0] + this.α * tb[0]),
    Math.round((1 - this.α) * ta[1] + this.α * tb[1])]
  );
  return this.intProjection;
}

有什么想法吗？

Answer 1

无穷大错误是由尝试在svg之外绘制的路径引起的。我可以通过向插值投影添加剪辑范围来删除这些错误。

interpolatedProjection(a, b) {
  let self = this;
  this.a = a;
  this.b = b;
  this.α = null;
  function raw(λ, φ) {
    let pa = self.a([λ *= 180 / Math.PI, φ *= 180 / Math.PI]), pb = self.b([λ, φ]);
    return [(1 - self.α) * pa[0] + self.α * pb[0], (self.α - 1) * pa[1] - self.α * pb[1]];
  }
  this.intProjection = d3.geo.projection(raw).scale(1)

    .clipExtent(this.extent); // this addition

  this.center = this.intProjection.center;
  this.translate = this.intProjection.translate;
  delete this.intProjection.scale;
  delete this.intProjection.translate;
  delete this.intProjection.center;
  return this.alpha(0.1);
}

我也在d属性中收到NaN错误，我可以通过不让补间索引达到值1来删除。

animation(timeout, newProjection) {
  let self = this;
  let projection = this.interpolatedProjection(this.prjFnc, newProjection);
  let path = d3.geo.path().projection(projection);
  this.svg.transition()
    .duration(timeout)
    .tween('projection', function() {
      return function(_) {

        if (_ === 1) { return; } // This addition

        self.alpha(_);
        self.paths.attr('d', path);
      };
    });
}

错误：<path>属性的值无效 - 在d3投影过渡期间 - Infinity＆amp;为NaN

1 个答案: