LiDAR data formats
Used for storing LiDAR (Light Detection and Ranging) data.
LiDAR is a remote sensing method that uses light in the form of a pulsed laser to measure distances to the Earth. These light pulses, combined with other data recorded by the airborne system, generate precise, three-dimensional information about the shape of the Earth and its surface characteristics.
The two primary data formats used for storing LiDAR data are the American Society for Photogrammetry and Remote Sensing (ASPRS) LAS format and the binary format. The LAS format, a public file format for the interchange of three-dimensional point cloud data, is well-documented and widely supported within the industry. The binary format, while less common, is used for its compact size and fast load times.
The LAS format (LAS for short) is a binary file format specifically for the storage and exchange of 3D point cloud data. It was developed by the American Society for Photogrammetry and Remote Sensing (ASPRS), and it has become a standard format for the exchange of LiDAR data. LAS files consist of a series of variable-length records, which allow for a wide range of information to be stored in addition to the basic 3D point data. These additional data can include RGB color values, intensity values, and various other forms of data that might be collected by the LiDAR system.
The binary format is simply a stored sequence of 0s and 1s, and it's especially useful for large LiDAR datasets because it's much more compact than the LAS format. However, reading binary data requires knowing exactly how the data are sequentially organized, so it's not as easy to use or as universally accepted as the LAS format.
Another format often used is the LAZ format, a compressed version of the LAS format. It uses an open-source lossless data compression library for data stored in the LAS format. It was designed to accommodate the needs of the LiDAR data and compresses LiDAR files to a size even smaller than if they were stored in a generic compressed format such as ZIP or RAR.
Importantly, these standard formats ensure compatibility between different hardware and software that are used to process LiDAR data. This allows researchers and professionals to share and use LiDAR data without having to worry about proprietary data formats. Interoperability between different systems is crucial in the remote sensing and GIS fields, and these LiDAR data formats deliver just that.
Overall, LiDAR data formats play a crucial role in how this data is stored, exchanged and accessed. Given the wide usage, the LAS format is frequently the preferred choice for LiDAR data storage due to its versatility and wide acceptance within the industry. Nonetheless, the choice of format will often depend on the size of the dataset, the need for additional attributes, and the requirements of the software that will be used to process the data. The ongoing development and support for these data formats help ensure that they continue to meet the evolving needs of the LiDAR community.
