Around 86,000 square kilometres of the province of British Columbia have been mapped using LiDAR and these high-tech point clouds are now released as open data. More about these big news can be found here. We decided to take the portal for a quick spin and try to find the Computer Science building of UBC Vancouver where we studied from 1996 to 1999. The experience was pleasant. Either go directly to the portal or visit the government page linking to it.
Then follow the steps shown in the images below to get to the data.
A few moments later the LiDAR tile in compressed LAZ format is yours to play with as long as you adhere to the rules of the Open Government License – British Columbia. After I downloaded the tile of UBC campus that contains the Computer Science building, I ran a quick lasinfo report whose output is shown below.
Everything looks fine. Unfortunately the time stamps are in “GPS week time” instead of “Adjusted GPS Standard time” so that the per-point information about which week of which year a point was collected is missing. A minor thing is the “coordinate resolution fluff” in the z coordinate. This means that although the z scale factor is set to 0.001 for storing millimeter precise elevations, the actual z coordinates stored in the LAZ file were rounded to full centimeters, so that a scale factor of 0.01 would be more appropriate.
Using the GUI of las2las I then clipped out a 500 meter by 300 meter part containing the Computer Science building,
-i bc_092g024_4_2_1_xyes_8_utm10_20170714.laz ^
-inside 481800 5456375 482300 5456675 ^
-odix _cut -olaz
and visualized the resulting LAZ file using lasview with option ‘-spike_free 1.0’ which can then be used for spike-free TIN generation by pressing hotkey <SHIFT>+<y>.
On the left is the Computer Science building. By hovering over two points on either end of the building and pressing <SHIFT>+<i> each time, I can measure that it is about 110 meters long. On the right, we see the much more famous UBC Forestry building. Below the same data as a point cloud colored by return type, where yellow points are single returns, red points are first of many, blue points are last of many and green points are intermediate returns.
Previously, access to LiDAR in British Columbia had been prohibitively expensive for many users. At the same time this precious data had often been sitting idle for years on government computers, never mind that it was collected with tax dollars. Now it is available to small and big businesses, non-profit organizations, recreational associations, scientists, academics and hobbyist alike allowing maximal exploration and exploitation for many different purposes, even some currently still unforeseen ones. Kudos to the Government of British Columbia for finally taking this step.