D3

圆锥投影 ​

¥Conic projections

圆锥投影将球体投影到圆锥体上，然后将圆锥体展开到平面上。圆锥投影具有 两条标准纬线。

¥Conic projections project the sphere onto a cone, and then unroll the cone onto the plane. Conic projections have two standard parallels.

conic.parallels(parallels) {#conic_parallels} ​

源代码 · 两条标准纬线 定义圆锥投影中的地图布局。

¥Source · The two standard parallels that define the map layout in conic projections.

geoConicConformal() ​

源代码 · 圆锥共形投影。平行线默认为 [30°, 30°]，从而导致顶部平坦。

¥Source · The conic conformal projection. The parallels default to [30°, 30°] resulting in flat top.

geoConicEqualArea() ​

源代码 · 阿尔伯斯等面积圆锥投影。

¥Source · The Albers’ equal-area conic projection.

geoConicEquidistant() ​

源代码 · 圆锥等距投影。

¥Source · The conic equidistant projection.

geoAlbers() ​

源代码 · 阿尔伯斯等面积圆锥投影。这是以美国为中心的 geoConicEqualArea 配置。

¥Source · The Albers’ equal area-conic projection. This is a U.S.-centric configuration of geoConicEqualArea.

geoAlbersUsa() ​

源代码 · 这是以美国为中心的三个 geoConicEqualArea 投影的复合投影：geoAlbers 用于美国本土 48 个州，阿拉斯加和夏威夷分别使用不同的圆锥等面积投影。阿拉斯加的比例缩小：它投影到其真实相对面积的 0.35 倍。请参阅 Albers 的美国领土图，了解适用于所有美国领土的扩展，并请参阅 d3-composite-projections，了解更多示例。

¥Source · This is a U.S.-centric composite projection of three geoConicEqualArea projections: geoAlbers is used for the lower forty-eight states, and separate conic equal-area projections are used for Alaska and Hawaii. The scale for Alaska is diminished: it is projected at 0.35× its true relative area. See Albers USA with Territories for an extension to all US territories, and d3-composite-projections for more examples.

组成投影具有固定的裁剪、中心和旋转，因此此投影不支持 projection.center、projection.rotate、projection.clipAngle 或 projection.clipExtent。

¥The constituent projections have fixed clip, center and rotation, and thus this projection does not support projection.center, projection.rotate, projection.clipAngle, or projection.clipExtent.