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Convert 'dggridR' grid object to hexify_grid

Source: R/dggrid_compat.R
from_dggrid.Rd

Creates a hexify_grid object from a 'dggridR' dggs object. This allows using hexify functions with grids created by 'dggridR' dgconstruct().

Usage

from_dggrid(dggs, radius_km = EARTH_RADIUS_KM)

Arguments

dggs

A 'dggridR' grid object from dgconstruct()

radius_km

Radius the grid is sized on, in km or as a body name. A dggs carries no radius, so the default is Earth's; pass this when the dggs describes a grid on another body.

Value

A hexify_grid object

Details

The 'ISEA' and 'FULLER' projections with HEXAGON topology are supported. Other configurations will generate warnings.

A dggs has no field for the body it is sized on, so the resolution is all that carries over and the result is an Earth grid unless radius_km says otherwise. Cell area follows from the radius, so it is read from the radius given rather than from the dggs.

The orientation carries over: pole_lon_deg, pole_lat_deg and azimuth_deg place the icosahedron as DGGRID's dggs_vert0_lon, dggs_vert0_lat and dggs_vert0_azimuth do, and a field left out takes its standard ISEA value.

The function validates that the 'dggridR' grid uses compatible settings:

  • Projection must be 'ISEA' or 'FULLER'

  • Topology must be "HEXAGON" (DIAMOND, TRIANGLE not supported)

  • Aperture must be 3, 4, or 7

See also

Other 'dggridR' compatibility: as_dggrid(), dggrid_43h_sequence(), dggrid_is_compatible()