LIDAR Format Letter

Open Letter about LIDAR format

March 2015.

We, the undersigned, are concerned that the current situation, where there is a defacto industry standard for storing LIDAR data, is being threatened by ESRI's introduction and promotion of an alternative closed format.

This is of concern as it reduces interoperability between applications and organisations, and introduces vendor lock-in.

We request that:

1. The OGC initiate the formalisation of a open standard for storing LIDAR data.
2. Users and sponsors of LIDAR data prioritise the use of an open format over a closed format when selecting software and services.
3. ESRI join efforts to support agreement around an open LIDAR format.

Signed

1. Name, Affiliation(s), Optional comment on interest in Open LIDAR format

Background

About LIDAR

LIDAR (Light Detection and Ranging) is a form of high precision range detection much like a radar system that uses laser light as the electromagnetic emission. One of LIDAR systems’ products is a “point cloud” data product that can be conceptualized as a series of point measurements representing distance from the sensor to a returned emission. A common storage format for these point cloud data is the LAS format.

To date, there has been common format for storing LIDAR data, the “LAS” format, and an open source library, libLAS, that can read and write the format. Rather than write their own format support, most vendors have simply used libLAS, and LAS has become an industry standard.

LAS limitations

Quoting Paul Ramsey:

LAS format is not without its drawbacks:

While it is a binary format and does not waste any space unnecessarily, neither does it apply any compression to the data it stores. That’s not good for archival use. Also, LAS stores points in scan order, so accessing any particular chunk of points involves reading the whole file. That’s not good for random access. Clearly there is a little more work to be done. Can LAS be improved? In fact, it already has been:

• An open source compression library LASzip can apply 20:1 lossless compression to LAS files, making them great for archival purposes.
• Other LAS users have experimented with re-ordering points in a LAS or LASzip file to allow random access to internal chunks of the LIDAR point cloud.

Basically, making LAS smaller and faster is not rocket science, and if the work were incorporated into libLAS then the whole LIDAR community could leverage it together, and the user community would only have one file type to interchange.

Closed "Optimized LAS" format from ESRI

ESRI has announced the release of an Optimized LAS format which is claimed to provide faster access and smaller file sizes. ESRI has also released a free tool which is claimed to convert LAS files to and from Optimized LAS.

However, the Optimized LAS format is not published, which locks out other applications being able to efficiently make use of the Optimized LAS format, effectively creating a vendor lock-in scenario.