geokachel

Official German open elevation, surface, building and point-cloud data — one interface, all sixteen Bundesländer, with the credit each licence requires.

Germany publishes superb elevation data and publishes it sixteen different ways. Every state runs its own surveying office, and they agree about almost nothing: where the UTM zone goes in a filename, whether a tile is one kilometre or two, whether a grid starts on an even easting or an odd one, whether you get a GeoTIFF or a million lines of text, whether there is a tile to address at all or only a twelve-gigabyte regional archive.

This is one interface over all of it, plus a record of which requests were actually answered, and when.

pip install geokachel

from geokachel import ground_tiles_for, read_raster, net

source = ground_tiles_for("BY")
print(source.attribution)
# Datenquelle: Bayerische Vermessungsverwaltung – www.geodaten.bayern.de

url = source.url_for(690, 5334)          # UTM32 kilometres, Munich
raster = read_raster(net.get_bytes(url))  # 1000 x 1000 metres of ground

What is in it

Plus Copernicus GLO-30 as a worldwide fallback, and the sixteen state coverage services (WCS) where a state runs one.

Three rules it keeps

An entry is a request that was answered, dated — never a portal page that says a thing exists. Every entry records the tile it was verified at and the bytes that came back, which is what makes geokachel check possible.

A credit is a licence obligation, not a caption. dl-de/by-2-0 and CC BY 4.0 both require a named credit. A height displayed without it is a height used outside its licence, so attribution is a required field on every source and carries the publisher's exact wording. A source whose licence forbids this kind of use is not in the registry at all. See NOTICE.

A gap is a gap. No state borrows its neighbour's ground, and nothing unsurveyed is guessed at: it is NaN, and it says so.

Three ways a tile has an address

Handled behind one function, because a caller should not have to care:

• computed — the name is arithmetic on two UTM kilometre numbers. Most states. A tile's address is a template and two integers, never a lookup.
• listed — the name carries a survey year (2005 in one tile, 2025 in its neighbour), so the state's own index is read once. What is taken out of it is a file name; the scheme, the host and the shape of the address stay ours, so a compromised index cannot redirect a fetch.
• archived — the state publishes no tile at all, only 0.5–12.5 GB regional archives. A zip keeps its index at its end, so one member comes out over HTTP range requests: 0.38 % of a 559 MB file, measured.

Checking that it is all still there

States move their files. In the two days this registry was built, four of them changed underneath it — one moved host entirely, one still lists tiles that 404, one carries dead share tokens, and one answers a stale row with HTTP 200 and an HTML apology. A checker that read status codes would have called all four healthy.

geokachel check              # every source, a few kB each, ~2 minutes
geokachel check sn- rp-      # just these
geokachel check --quiet      # only what is wrong; exit 1 if anything is
geokachel credits BY TH      # the exact credit those states require

A source passes only when the bytes are what it claims — II* for a TIFF, LASF for a cloud, a root element for CityGML, numbers for a text grid, a directory that still holds the square kilometre it held before.

It is deliberately not a test suite: one that needs sixteen state portals to be up fails on their maintenance window and teaches people to ignore red. It is a command with an exit code, meant for a scheduled job.

What it deliberately does not do

It does not choose your coordinate frame. You get a north-up raster in the source's own UTM with NaN for unknown. Putting that on your own axes is yours, because the right answer differs for a shadow model, a flood model and a map — and because UTM grid north is up to 2.3° off true north in Germany, which some callers must correct for and others must not.

It does not geocode. state= is a required argument. A library that reverse-geocoded every call would rate-limit whoever looped over ten thousand plots, and that is not a failure to inflict from inside a dependency.

It does not fetch anything itself. Every function that needs bytes takes a callable. geokachel.net is a polite default — a pause between requests, a size cap, a User-Agent — and you should set geokachel.net.USER_AGENT to something with your own contact in it before pulling anything in anger. These are public offices publishing at their own expense.

Installing

Requires Python 3.11+. Depends on numpy, defusedxml and requests — no GDAL, no rasterio, no pyproj. The GeoTIFF reader and the UTM projection are both here, because a hundred-megabyte wheel to read a single-band raster is a poor trade.

Licence

MIT, for the software. The data is somebody else's and carries its own terms — read NOTICE before you publish anything derived from it.

Not affiliated with any Landesvermessungsamt, the AdV, the BKG, ESA or Copernicus. Their names appear only inside the credits their licences require.