evetion / lasindex.jl

Pure Julia reader of lasindex .lax files

LASindex.jl

Pure Julia reader of lasindex .lax files. Translates the .lax file to a quadtree from the RegionTrees package and provides a bounding box intersect method to retrieve a vector of ranges.

julia> using LASindex
julia> using FileIO

julia> laxfile = joinpath("sample", "Palm Beach Post Hurricane.lax");
julia> qt = load(laxfile)
INFO: Processed Palm Beach Post Hurricane.lax with 1924631 points.
Cell: RegionTrees.HyperRectangle{2,Float64}([955000.0, 885000.0], [32000.0, 32000.0])

julia> using StaticArrays
julia> bbox = SVector(955000.0, 985002.0, 885000.0, 988800.0);
julia> r = LASindex.intersect(qt, bbox)
1-element Array{UnitRange{Integer},1}:
 1:1924631

The resulting ranges can be used in combination with LasIO or LazIO to stream a small subset of a (larger than memory) dataset.

using LasIO
header, points = load("Palm Beach Post Hurricane.las", mmap=true)

intersected_points = points[LASindex.intersect(qt, bbox)]

Note that all points inside the bounding box are given, but not all points given are inside the bounding box. In other words, because of how lasindex groups ranges together, some ranges will include points outside the bounding box.

Background

LAX files are quadtree indexes used by the LASTools suite [1] if present. You can generate them with lasindex -i *.laz[2]. There's a good introduction to lasindex here [3].

• [1] https://rapidlasso.com/lastools/
• [2] https://github.com/LAStools/LAStools/blob/master/bin/lasindex_README.txt
• [3] https://www.youtube.com/watch?v=FMcBywhPgdg

Future

I'd rather use Cxx to call the lasindex c++ code directly, but at the moment the Cxx package is harder to install on Windows than compiling the lastools shared library itself.

An example how to interface with lastools directly is provided in example/cxx.jl

lasindex.jl's Issues

Replace SVector for bbox intersection

with generic bounding box type that has a well defined order for min, max tuples.

Info about upcoming removal of packages in the General registry

As described in https://discourse.julialang.org/t/ann-plans-for-removing-packages-that-do-not-yet-support-1-0-from-the-general-registry/ we are planning on removing packages that do not support 1.0 from the General registry. This package has been detected to not support 1.0 and is thus slated to be removed. The removal of packages from the registry will happen approximately a month after this issue is open.

To transition to the new Pkg system using Project.toml, see https://github.com/JuliaRegistries/Registrator.jl#transitioning-from-require-to-projecttoml.
To then tag a new version of the package, see https://github.com/JuliaRegistries/Registrator.jl#via-the-github-app.

If you believe this package has erroneously been detected as not supporting 1.0 or have any other questions, don't hesitate to discuss it here or in the thread linked at the top of this post.