Convert Icosa Triangle coordinates to PLANE coordinates

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,
  polyhedron = c("icosahedron", "octahedron", "tetrahedron")
)

Arguments

icosa_triangle_face

Triangle face number (0-19 on the icosahedron), integer or vector

icosa_triangle_x

X coordinate on triangle face

icosa_triangle_y

Y coordinate on triangle face

polyhedron

The solid whose faces are unfolded: "icosahedron" (default), "octahedron" or "tetrahedron"

Value

Data frame with columns:

plane_x

X coordinate in PLANE space (range ~0 to 5.5 on the icosahedron)

plane_y

Y coordinate in PLANE space (range ~0 to 1.73)

Details

Equivalent to 'dggridR' dgPROJTRI_to_PLANE().

The PLANE layout of the icosahedron arranges all 20 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. The octahedron lays its four diamonds side by side, each a northern face over its southern one; the tetrahedron lays face 3 in the middle of a triangle of edge 2 with the three faces around vertex 0 at its corners.

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_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)