lazproof-geo

Prove that a LAS/LAZ output is an exact, order-preserving spatial subset of its source.

Point counts and bounding boxes are not enough to catch reordered records, changed attributes, a different Extra Bytes schema, or a subtly modified header. lazproof independently streams both files and hashes complete structured point records in order, without cropping the source and without requiring PDAL.

Quick start

python -m pip install lazproof-geo
lazproof verify source.laz result.laz \
  --inside boundary.geojson \
  --report proof.json

Exit codes are stable:

• 0: every requested check passed;
• 1: verification completed and found a mismatch;
• 2: the files, geometry, or invocation were invalid.

Reproducible example

Generate a complete suite of tiny synthetic LAZ files, run every verification, and write one JSON report per case:

python examples/run_examples.py

The suite exercises both successful and intentionally failing results:

Generated files are placed under examples/generated/. To run one case through the CLI instead:

lazproof verify examples/generated/source.laz examples/generated/valid.laz \
  --inside examples/generated/mask.wkt \
  --report examples/generated/valid-cli.json

A report contains explicit checks:

{
  "verified": false,
  "expected_points": 5,
  "result_points": 5,
  "checks": {
    "source_unchanged": true,
    "header_preserved": true,
    "point_count_matches": true,
    "dimension_hashes_match": false,
    "all_result_points_inside": true
  }
}

Python API

from shapely.geometry import box
from lazproof import VerificationReport, verify_subset

report: VerificationReport = verify_subset(
    "source.laz",
    "result.laz",
    box(0, 0, 100, 100),
)
assert report.verified, report.mismatches

verify_subset(source, result, geometry=None, *, chunk_size=250_000) reads data in bounded chunks. With no geometry, the result must be an exact full copy.

What is proved

• LAS version, point format, dimension schema, scales, offsets, and CRS match.
• The result contains exactly the source records selected by the polygon.
• Every raw point dimension matches in the original record order.
• Every result point lies inside the selection geometry.
• The source file hash is unchanged during verification.

What is not proved

• The source data is correct, authentic, or appropriate for a particular use.
• The CRS describes the real-world location correctly.
• A non-spatial filter was applied as intended.
• The source remained unchanged before or after the verification run.
• Waveform point formats 4, 5, 9, and 10 are supported; version 0.1 rejects them.

Selection geometry may be WKT, .wkt, GeoJSON, or a Fiona-supported vector layer. Run lazproof --help for all options.

The pre-release and launch checks are listed in docs/release-checklist.md.

Development

python -m pip install -e ".[test]"
python -m ruff check .
python -m ruff format --check .
python -m pytest

Copyright 2026 Alena Nikitina. Licensed under the Apache License 2.0.