False precision in the English Lidar release

Great commentary from Martin Isenburgon of LASTools fame on releasing data with false precision. This deals with the new open data release by the Environment Agency in England. So far LiDAR-derived DTM and DSM rasters have been released for 72% of the entire English territory at horizontal resolutions of 50 cm, 1 m, and 2 m. They can be downloaded here. The rasters are distributed as zipped archives of tiles in textual ASC format (*.asc). 

Martin gives us a cautionary tale on how not to release national data. It is not the ASC format that he has problems with, but the vertical precision. He says:

"The vertical resolution ranges from femtometers to attometers. This means that the ASCII numbers that specify the elevation for each grid cell are written down with 15 to 17 digits after the decimal point."

Example heights might be something like: 79.9499969482421875 or 80.23999786376953125. These data should be resolved to about the cm, not attometer, whatever that is. Crazy man!

Read the full post: http://rapidlasso.com/2015/09/02/england-releases-national-lidar-dem-with-insane-vertical-resolution/

Big Data for sustainability: an uneven track record with great potential

An interesting position piece on the appropriate uses of big data for climate resilience. The author, Amy Luers, points out three opportunities and three risks.

She sums up:

"The big data revolution is upon us. How this will contribute to the resilience of human and natural systems remains to be seen. Ultimately, it will depend on what trade-offs we are willing to make. For example, are we willing to compromise some individual privacy for increased community resilience, or the ecological systems on which they depend?—If so, how much, and under what circumstances?"

Read more from this interesting article here.