las-laz-js demo

Drop a LAS or LAZ file here

Your file never leaves your browser. It is read locally, in a Worker, a window at a time.

Open a file to see its header, coordinate system and records.

VLRs

Extra bytes

No extra bytes.

Splits the selection (draw a polygon round the muckpile, Inside polygon) or the whole cloud into fragments, rocks, with findFragmentsParallel (tiles of the cloud on every core). Size is a fragment's intermediate axis b, the sieve-size estimate. Only the visible surface is measured; flat patches and rocks under the lower limit are fines, and the surface in no fragment (gaps, the toe, flat ground) is reported on its own as unresolved, not as fines. The line under Find fragments says what the cloud can resolve. When the read was thinned by Max points, the run reads every point (inside the polygon) itself, so it measures the full density while the view stays light.

What a cloud can resolve

Point spacing Resolution What you get

≤ 0.017 m fine Rocks down to about 0.5 m come out whole; a size curve from the floor up. Photogrammetry: ODM --pc-quality ultra at full image scale (0.016 m, about 1.5 cm).

≤ 0.035 m coarse Rocks over about 0.7–1 m only (ODM default, 0.028 m); P-values under the floor are not sizes.

≤ 0.05 m oversize Rocks over about 1–1.5 m only: oversize, not a size curve.

coarser unresolved No rocks: patches of surface (an 8 cm survey found none at all).

The floor, the smallest rock measured, is 30 point spacings. Measured on S4_250_403 against 118 hand-drawn rocks. A read thinned by Max points is coarser than the file: set Max points to 0.

Fragments

Method Min points

Max distance (m) Concave angle (°) Plane distance (m)

Fill Camera as viewpoint

Runs on the whole cloud

Show outlines

Colour Bins

over m

Size curve

sizeDistribution: % passing by size b. The fit uses the coarse part only (from Fit from up), where a scan's sizes hold; below the measured curve it is dashed: extrapolated, not measured.

Model Weight Fit from (%) Lower limit (m) Upper limit (m) Fines (%) Fines size (m)