Interface GeoStream

A D3 geo stream. D3 transforms geometry using a sequence of function calls, rather than materializing intermediate representations, to minimize overhead. Streams must implement several methods to receive input geometry. Streams are inherently stateful; the meaning of a point depends on whether the point is inside of a line, and likewise a line is distinguished from a ring by a polygon. Despite the name “stream”, these method calls are currently synchronous.

interface GeoStream {
    lineEnd(): void;
    lineStart(): void;
    point(x, y, z?): void;
    polygonEnd(): void;
    polygonStart(): void;
    sphere?(): void;
}

Methods

lineEnd lineStart point polygonEnd polygonStart sphere?

Methods

lineEnd

  • lineEnd(): void

  • Indicates the end of a line or ring. Within a polygon, indicates the end of a ring. Unlike GeoJSON, the redundant closing coordinate of a ring is not indicated via point, and instead is implied via lineEnd within a polygon.

    Returns void

lineStart

  • lineStart(): void

  • Indicates the start of a line or ring. Within a polygon, indicates the start of a ring. The first ring of a polygon is the exterior ring, and is typically clockwise. Any subsequent rings indicate holes in the polygon, and are typically counterclockwise.

    Returns void

point

  • point(x, y, z?): void

  • Indicates a point with the specified coordinates x and y (and optionally z). The coordinate system is unspecified and implementation-dependent; for example, projection streams require spherical coordinates in degrees as input. Outside the context of a polygon or line, a point indicates a point geometry object (Point or MultiPoint). Within a line or polygon ring, the point indicates a control point.

    Parameters

    • x: number

      x-coordinate of point.

    • y: number

      y-coordinate of point.

    • Optional z: number

      Optional z-coordinate of point.

    Returns void

polygonEnd

  • polygonEnd(): void

  • Indicates the end of a polygon.

    Returns void

polygonStart

  • polygonStart(): void

  • Indicates the start of a polygon. The first line of a polygon indicates the exterior ring, and any subsequent lines indicate interior holes.

    Returns void

Optional sphere

  • sphere(): void

  • Indicates the sphere (the globe; the unit sphere centered at ⟨0,0,0⟩).

    Returns void

Settings

Member Visibility

Theme

On This Page