hexify_icosa_tri_to_plane: Convert Icosa Triangle coordinates to PLANE coordinates

In hexify: Equal-Area Hex Grids on the 'Snyder' 'ISEA' 'Icosahedron'

Convert Icosa Triangle coordinates to PLANE coordinates

Description

Transforms icosahedral triangle coordinates to the 2D PLANE representation (unfolded icosahedron). Each triangle is rotated and translated to its position in the unfolded layout.

Usage

hexify_icosa_tri_to_plane(
  icosa_triangle_face,
  icosa_triangle_x,
  icosa_triangle_y
)

Arguments

icosa_triangle_face	Triangle face number (0-19), integer or vector
icosa_triangle_x	X coordinate on triangle face
icosa_triangle_y	Y coordinate on triangle face

Details

Equivalent to 'dggridR' dgPROJTRI_to_PLANE().

The PLANE layout arranges all 20 icosahedral faces into a roughly rectangular region. Faces 0-4 and 5-9 form the upper row, while faces 10-14 and 15-19 form the lower row. Adjacent faces share edges in this representation.

Value

Data frame with columns:

plane_x	X coordinate in PLANE space (range ~0 to 5.5)
plane_y	Y coordinate in PLANE space (range ~0 to 1.73)

See Also

hexify_cell_to_plane for direct cell ID conversion, hexify_lonlat_to_plane for lon/lat to PLANE

Other coordinate conversion: hexify_cell_id_to_quad_ij(), hexify_cell_to_icosa_tri(), hexify_cell_to_lonlat(), hexify_cell_to_plane(), hexify_cell_to_quad_ij(), hexify_cell_to_quad_xy(), hexify_grid_cell_to_lonlat(), hexify_grid_to_cell(), hexify_icosa_tri_to_quad_ij(), hexify_icosa_tri_to_quad_xy(), hexify_lonlat_to_cell(), hexify_lonlat_to_plane(), hexify_lonlat_to_quad_ij(), hexify_quad_ij_to_cell(), hexify_quad_ij_to_icosa_tri(), hexify_quad_ij_to_xy(), hexify_quad_xy_to_cell(), hexify_quad_xy_to_icosa_tri(), hexify_roundtrip_test()

Examples

# Get PLANE coordinates from triangle coordinates
fwd <- hexify_forward(lon = 2.35, lat = 48.86)
plane <- hexify_icosa_tri_to_plane(
  icosa_triangle_face = fwd["face"],
  icosa_triangle_x = fwd["icosa_triangle_x"],
  icosa_triangle_y = fwd["icosa_triangle_y"]
)
print(plane)

hexify documentation built on March 1, 2026, 1:07 a.m.