How it works
The grid is three numbers: an origin at easting 140 000 m, northing 20 000 m, the same in every
UTM south zone; 720 pixels on a tile's edge, at every resolution; and the resolution. So a tile is
7.2 km on a side at 10 m, 14.4 km at 20 m and 43.2 km at 60 m, and its id says all of it:
43S_R0060_0005_0094 is zone 43 south, 60 m pixels, column 5 and row 94 counted from the origin.
Tiles nest whenever one resolution divides another: a 60 m tile holds 3 x 3 tiles at 20 m and
6 x 6 at 10 m, and a tile's parent is its column and row divided and rounded down. Pick a point to
see its 60 m tile with the finer tiles inside it.
The lattice is square in the zone's own metres, so on the globe its columns are not meridians:
they lean away from them towards the zone's edges, more the further south. Each zone has its own
lattice, so where two zones meet the lattices cross at an angle. "Lattice past the zone edge" carries
this zone's lattice over the next zones' ground: the same place has a tile in each, in two
coordinate systems, and a tile id says which zone it means.
The origin is chosen to line up with Sentinel-2. Its tiles start on a 60 m lattice through
easting 0 and, in the south, through the equator, which is northing 10 000 000, not a multiple of 60.
At 10 m and 20 m the pixels here are Sentinel-2's own; at 60 m they sit 20 m off in each direction,
a constant shift that a warp absorbs.
The Australian Antarctic Territory is claimed south of 60° S from 45° E to 160° E,
less Adelie Land (136° E to 142° E): twenty UTM zones, 38 to 57. Heard Island and
Macquarie Island are in zones 43 and 57.
Click the globe, or paste a longitude and latitude or a tile id (the older L1 and L2 names
for 60 m and 10 m read too).
- The scheme is the aatgrid R package's, which has a
fuller explorer on UTM maps of the coast.
The Heard Island anchors and the Sentinel-2 alignment checked here are from its tests and notes.
- UTM is transverse Mercator by Kruger's series (Karney 2011), as in PROJ,
checked against PROJ; Sentinel-2 tiles as on the MGRS and Sentinel-2 page.
- Coastline: Natural Earth, public domain.