Formats

Point clouds

Clouds are published as compressed LAS, one file per tile, with tiles cut on a fixed grid so a reuser can take only the area they need instead of the whole set. Intensity and return number are preserved. Where a classification pass was run, the classified cloud is a separate file and the unfiltered cloud stays available.

Tile extents are listed in the set manifest, so the tiles covering a given area can be worked out before downloading anything.

Meshes

Meshes are published as both OBJ with a companion material file and glTF binary. The glTF is the better choice for viewing; the OBJ is kept because it survives round trips through older survey software without losing the material assignment.

Triangle counts are given in the catalog. Decimated meshes state the count they were reduced to and the method used, since that affects whether volume figures are comparable.

Textures

Texture sets are PNG pages at 8192 by 8192 pixels, numbered in the order the mesh references them. Texture pages are the bulk of the transfer size on most sets. A set with four pages is carrying roughly a gigabyte of texture before anything else is counted.

Manifests and checksums

Each set directory contains a plain text manifest listing every part with its byte size and SHA-256. The manifest is a few kilobytes and is worth fetching first. After a transfer, verifying against the manifest is the only reliable way to tell a truncated part from a complete one, since a part that stopped early is still a readable archive.

Manifests are not regenerated when a set is reprocessed. A reprocessed set is published as a new dated directory with its own manifest.

Coordinate systems

Georeferenced sets state their coordinate reference system in the manifest header. Sets delivered in a local system state that instead and include the control point list, so they can be tied into a national grid afterwards rather than being silently transformed here.