WebDggrid

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webdggrid / IDGGSProps

Interface: IDGGSProps ​

Defined in: webdggrid.ts:136

Full configuration of a Discrete Global Grid System.

A DGGS is fully defined by its polyhedron orientation (poleCoordinates, azimuth), the subdivision scheme (aperture), the cell shape (topology), and the map projection (projection).

Pass this object to Webdggrid.setDggs to switch between grid configurations at runtime.

Example ​

ts
const myDggs: IDGGSProps = {
  poleCoordinates: { lat: 58.28, lng: 11.25 }, // Snyder orientation
  azimuth: 0,
  aperture: 4,
  topology: Topology.HEXAGON,
  projection: Projection.ISEA,
};
dggs.setDggs(myDggs, 5);

Properties ​

aperture? ​

optional aperture?: 7 | 3 | 4 | 5

Defined in: webdggrid.ts:162

Subdivision aperture — the number of child cells each parent cell is divided into when moving to the next finer resolution.

ApertureCells at res r (HEXAGON/ISEA)
32 + 10 × 3^r
42 + 10 × 4^r
72 + 10 × 7^r

Aperture 4 is the most common choice and is the default. Ignored if apertureSequence is specified.

apertureSequence? ​

optional apertureSequence?: string

Defined in: webdggrid.ts:181

Mixed aperture sequence (e.g., "434747").

When specified, each character defines the aperture for that resolution level. The maximum resolution is limited to the length of the sequence string.

Constraints:

  • Only valid for HEXAGON topology
  • Only characters '3', '4', and '7' are allowed
  • SEQNUM addressing is not supported (operations will fail)
  • Z3/Z7 hierarchical indexing is not supported

Example ​

ts
// Resolution 1 uses aperture 4, res 2 uses aperture 3, etc.
apertureSequence: "434747"

azimuth ​

azimuth: number

Defined in: webdggrid.ts:148

Azimuth of the icosahedron pole in decimal degrees. Rotates the grid around the pole axis. Defaults to 0.

poleCoordinates ​

poleCoordinates: Coordinate

Defined in: webdggrid.ts:143

Geographic location of the icosahedron pole used to orient the grid. Changing this rotates the entire grid on the globe, which can be used to minimise cell distortion over a region of interest. Defaults to { lat: 0, lng: 0 }.

projection ​

projection: Projection

Defined in: webdggrid.ts:185

Projection used to map the polyhedron faces onto the sphere. See Projection.

topology ​

topology: Topology

Defined in: webdggrid.ts:183

Shape of each cell. See Topology.