Graticule Transform
The graticule transform generates a reference grid for cartographic maps. A graticule is a uniform grid of meridians and parallels for showing projection distortion. The default graticule has meridians and parallels every 10° between ±80° latitude; for the polar regions, there are meridians every 90°.
This transform generates a new data stream containing a single GeoJSON data object for the graticule, which can subsequently be drawn using the geopath or geoshape transform. This transform uses the d3-geo library.
Example
Transform Parameters
| Property | Type | Description |
|---|---|---|
| extentMajor | Array[ ] | The major extent of the graticule as a two-element array of coordinates. |
| extentMinor | Array[ ] | The minor extent of the graticule as a two-element array of coordinates. |
| extent | Array[ ] | Sets both the major and minor extents to the same values. |
| stepMajor | Number[ ] | The major step angles of the graticule (default [90, 360]). |
| stepMinor | Number[ ] | The minor step angles of the graticule (default [10, 10]). |
| step | Number[ ] | Sets both the major and minor step angles to the same values. |
| precision | Number | The precision of the graticule in degrees (default 2.5). |
Usage
{"type": "graticule", "stepMinor": [15, 15]}
Generates a new graticule data stream with minor parallels and meridians spaced every 15°.