What is the LAS file format?
.las is a binary file that stores LiDAR point data records. LiDAR (Light Detection And Ranging) is a remote-sensing technology that emits laser pulses toward a target and measures the reflected light with specialized sensors to calculate precise 3D distances and positions. Though early uses were concentrated in atmospheric science, LiDAR is now central to aerial surveying, autonomous vehicle navigation, urban 3D mapping, forestry analysis, and archaeological prospecting.
Data gathered by a LiDAR device is saved to a .las file in a compact binary layout. Every .las file begins with the 4-byte ASCII signature LASF at byte offset 0, followed by a public header block that carries coordinate scale factors, bounding-box extents, and point counts. Each point data record stores at minimum X, Y, Z coordinates along with intensity and return number; later point formats add RGB color, near-infrared, GPS time, and full-waveform data.
The .las standard was first proposed by ASPRS (American Society for Photogrammetry and Remote Sensing) as an open format for storing and exchanging LiDAR data. LAS 1.0 appeared in 2003; the current LAS 1.4 revision, finalized in 2011, extended point-count fields to 64 bits and added new attribute classes. When storage is a concern, .las files are commonly compressed into the .LAZ format - typically achieving 85-90 % size reduction without any data loss. Other 3D point-cloud interchange formats include .E57 and .PLY.
Note: the .las extension is also used by the unrelated Log ASCII Standard format for oil-well log data - a plain-text file beginning with ~V rather than the binary LASF signature.
Security & safety
RISK: LOWA LAS file is measurement data with no executable code - safe to open in point-cloud software. The only practical risks are size (multi-GB files can overwhelm low-RAM machines - use LAZ or tiling) and confidentiality (survey/scan data of private property or infrastructure may be sensitive; mind cloud uploads). Verify which .las you have: if it opens as readable text starting with '~V', it's a Log ASCII Standard well log, not LiDAR.
Format details
in a nutshell- Log ASCII Standard (LAS) well log - A plain-text oil/gas and water-well log format from the Canadian Well Logging Society storing depth-indexed geophysical curves; starts with a '~Version' section, not 'LASF'.
- Generic 'LASer'/saved-state files - A few games and legacy apps use .las for saved data or scripts; unrelated to point clouds.
Programs that open LAS files
Windows6 apps
Global Mapper
Paid Open the .las; strong LiDAR module for classification, gridding and export. (Vendor moved to bluemarblegeo.com.) 
CloudCompare
Open-source File > Open the .las to view, measure, classify and crop the point cloud. Best free LiDAR viewer. 
QGIS
Open-source Add the .las as a point-cloud layer (PDAL-based) to view, style by classification and build terrain.
FME (Form / Flow)
Paid Use FME to convert/transform LAS between formats and coordinate systems. (Now 'FME', formerly FME Desktop.)
LAStools
Freemium Command-line/ArcGIS tools (laszip, las2las, lasview) for processing; laszip compresses LAS to LAZ. 
macOS2 apps
Linux2 apps
PDAL
Open-source Command line: 'pdal info file.las' inspects it; 'pdal translate' converts LAS<->LAZ/other formats. Technical details
deep spec| Magic bytes | `LASF` (hex `4C 41 53 46`) at byte offset 0 |
| Binary encoding | Little-endian binary throughout; not human-readable |
| Public header size | Fixed 227 bytes in LAS 1.4; contains file signature, point counts, bounding box, scale factors, and CRS offsets |
| Point data record formats | 11 standardized formats (0-10) defined in LAS 1.4; each adds a different attribute set |
| Coordinate storage | X, Y, Z stored as 32-bit signed integers; real-world values recovered via per-axis scale factor and offset stored in the header |
| Maximum point count | 64-bit point-count fields in LAS 1.4 support up to 2‶³ − 1 points per file |
| Point attributes | Intensity, return number, scan angle, classification, RGB color, near-infrared channel, GPS time, and waveform data (availability varies by format number) |
| Point classification codes | Standardized values 0-255; e.g. 2 = Ground, 3-5 = Vegetation, 6 = Building, 9 = Water |
| Coordinate reference system | CRS stored in Variable-Length Records (VLRs) as WKT strings or GeoTIFF projection keys |
| Variable-Length Records (VLRs) | Optional metadata blocks between the public header and point data; Extended VLRs (EVLRs) may follow point data in LAS 1.4 |
| Native compression | None; raw binary. Lossless LASzip compression produces `.laz` files (~85-90 % smaller) |
| MIME type | `application/octet-stream` (no IANA-registered media type specific to LAS) |
| Extension name collision | `.las` also used by Log ASCII Standard (oil-well log text files), which start with `~V` rather than the binary `LASF` signature |
| Released | 2003 (LAS 1.0); current LAS 1.4 published 2011, ASPRS |
| Open standard | Yes · royalty-free |
| Specification | www.asprs.org |
LAS conversions
Community Q&A
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