plotly / plotly/plotly.js

[BUG]: geo projections lose their D3 default rotation

未关闭
#7,949 1 条评论 0 个 reaction 已指派 0 人 在 GitHub 查看

还没有人认领这个 Issue。

bug P3 plotly-internal size: 3
主要语言
JavaScript
星标
18.3k
派生
2k
平均合并
2 天 12 小时
30 天内合并 PR
28

描述

Description

Geo.updateProjection calls projection.rotate([-rotation.lon, -rotation.lat, rotation.roll]) unconditionally. For a world-scope map projection.rotation defaults to [0, 0, 0], so any rotation the D3 projection ships with is discarded.

Six of the projections in plotly.js carry a non-identity default rotation:

projection D3 default rotation
albers [96, 0, 0]
bertin1953 [-16.5, -42, 0]
gringorten quincuncial [-90, -90, 45]
peirce quincuncial [-90, -90, 45]
sinu mollweide [-20, -55, 0]
wiechel [0, -90, 45]

For the quincuncials and wiechel that rotation is geometric: it places the sphere in the polar aspect and tilts the square 45°, and is applied inside the projection's own constructor:

// d3-geo-projection/src/quincuncial/index.js
return projection(projectQuincuncial)
    .rotate([-90, -90, 45])
    .clipAngle(180 - 1e-3);

Replacing it renders a different orientation from the one D3 defines. (For albers, D3's [96, 0, 0] preconfigures it for the USA, so discarding it is probably intended.)

Screenshots/Video

For 'peirce quincuncial':

D3 projection Plotly projection
Image Image
Steps to reproduce
  • Be on master
  • Open Plotly devtools
  • Enter the following snippet into the browser console:
Plotly.newPlot(gd, [{
    type: 'choropleth',
    locations: ['GHA', 'ARG', 'AUS', 'CAN'],
    z: [1, 2, 3, 4],
    showscale: false
}], {
    geo: { projection: { type: 'peirce quincuncial' }, fitbounds: false },
    height: 800
});
  • Note that
  • Expected: the canonical peirce quincuncial orientation.
  • Actual: rendered with rotation [0, 0, 0].
Screenshots
Notes
  • A fix needs to compose the requested rotation onto each projection's default rather than replace it, since d3.geoProjection.rotate() replaces
  • This was discovered in #7948. It's possible that this is intentional for a good reason, but it would be worth looking at changing it regardless.

贡献指南

打开贡献指南

从这里开始

  1. 先读完整个 Issue,再读项目的贡献指南。
  2. 在 Issue 下留言说明你要接手 —— 这能避免两个人做同样的事。
  3. Fork 仓库,在一个分支上完成修改。
  4. 提交 Pull Request,并在描述里引用这个 Issue 编号。

调研方向

从 Geo.updateProjection 开始,将其旋转处理方式与 D3 投影构造函数进行比较,尤其是 issue 中描述的 quincuncial 和 wiechel 默认值。在浏览器中复现 peirce quincuncial 示例,然后验证渲染出的方向在应用请求的旋转的同时,仍保留投影的规范默认值。

由索引模型根据 Issue 内容生成。

评估

技术栈
javascript
领域
data-visualization
Issue 类型
缺陷
难度
3/5
预计耗时
1-2 天
活跃度
活跃
描述清晰度
基本清楚
新手友好度
72/100

把新 issue 发到你的邮箱

精选适合新手参与的 GitHub issue 摘要。