Open Source for LiDAR

Its 2011 already and open source isnt the cool new buzzword it once was. The open source model is now mainstream: many of the websites you visit every day with Firefox would not exist without the Linux operating system and the Apache web server. In our own geospatial industry, most of the software packages we use are built with at least some open source components. But focusing in even narrower, what about our lidar community: are there open source applications and libraries that can help you work with point cloud data? How can you find the open source solutions you need, and what do you need to know about the open source model in order to do so?

The answer to that first question is a resounding yes, and this is the first article in a new Lidar News column dedicated to answering all these questions.

One future article, for example, will introduce you to lastools [1], a set of command line tools for fast filtering, cropping, tiling, and compression of very large LAS data sets. Much of the lastools suite is open source, which means lidar workers can use the tools without having to pay any licensing fees just download, install, and run.

For lidar developers, another article will introduce libLAS [2] and its coming successor PDAL, two C++ libraries which provide file format conversion, filtering and transformation algorithms, spatial indexing, and more. These libraries are also open source, so you can include the source code right in your own applications for free. Think about that: at no cost to you or your firm, you can get source code that faithfully implements the LAS standard and also implements reprojection algorithms across hundreds of coordinate systems. And it implements these efficiently, and it comes with support from the lidar development community.

Other articles in this column will introduce other libraries and tools that provide advanced mesh generation, feature detection, and visualization.

This column will cover more than just the actual applications and their source code, however. If you are going to use open source in your products or in your workflows, youll need to understand just what the open source model is. How does an open source license work, and what are the pros and cons of the different licenses in use today? How do you get support for a product that often doesnt seem to have a corporate entity standing behind it? How do you work with (and within!) the open source development community to get bugs fixed and new features added? And, perhaps most importantly, because you dont want to be using poor quality or unmaintained software, how do you know if a particular open source package is actively being maintained and used?

Admittedly these questions arent particularly lidar-specific, but you need to know the answers if you are going to bring open source into your shop. There are certainly more comprehensive and more authoritative articles and books written on these topics than I can provide here, but this column will give you an introduction and some pointers on where to learn more.

Beyond the source code and the support and the community, the open source model touches on some other areas as well, such as open data. Many of you will know about Open Street Map (OSM) [3]. While the OSM team built their ecosystem on top of open source code, their real contribution to the world is that of open data. Just like source code, there are some data sets available with licensing terms that permit free, public access and redistribution. Lidar users need data, so this column will talk about open data and its licensing terms, as well as survey some of the high-quality free lidar data sets that are available for you to download, modify, and redistribute.

Finally, one other area this column will cover is the use of open standards within the lidar community. There is a lot going on in this area right now the proposed LAS 1.4 specification, the new E57 standard, and 3D activities within OGC. Open source developers are very sensitive to issues of interoperability and compatibility and so its no surprise that the open source community has long proved to be a valuable resource in standards development, adoption, and proliferation.

We all know the use of lidar technology is growing very rapidly right now, and as practitioners in the field were often hard-pressed to keep up with new technologies, new workflows, new data. The use of open source software is one way to keep up to date and maybe even gain a little competitive edge. As a long-time user, developer, and advocate of the open source model, I look forward to exploring the intersection of lidar and open source.




About the Author

Michael P. Gerlek

Michael P. Gerlek... Michael is an independent consultant at Flaxen Geo. Prior to starting Flaxen Geo in 2010, Michael spent over a decade working at LizardTech in various capacities, including Director of Engineering, working on image processing, image compression (MrSID, JPEG 2000), and OGC standards. Michael is very active in the open source geospatial community; he was a founding member of the Open Geospatial Foundation OSGeo and helps to run its Seattle chapter. Prior his geospatial career, he worked in the high performance computing and compiler industry, including jobs at both Tera and Intel and an MS degree at the Oregon Graduate Institute. Michael and his family live on a minor US outlying island in the Puget Sound.
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