Getting Hold of Lidar Data

[Simon Ritchie]

Initially, lidar units were mounted on satellites or aircraft.  Satellites can survey very large areas, but only government agencies can afford them.  Lidar systems in aircraft are cheaper, but stil prohibitive - £100,000 or more for the equipment is typical, plus the cost of hiring the aircraft.  A survey run from an aircraft will cost thousands of pounds per hour.  

Construction companies often run their own lidar surveys for planning large projects.  If you're going to build a few miles of road, and you need to excavate tons of earth from one place and dump it somewhere else to level the route, it's handy to know exactly how much earth is involved before you start.  A lidar survey is a good but expensive way to figure that out.

You don't necessarily need to do your own lidar survey, one may already be available. In the UK, the Environment Agency (EA) publishes lidar surveys of large areas of the country on its website.  They plan to cover the whole of England by the end of 2020 and they are trying to raise the funds to survey the whole of the UK.  You can download their data for free and there are free software tools to help interpret them.  

However, the standard EA data is only accurate to 1m, which is a bit grainy for some purposes.  Some of their  datasets are accurate to 0.5m and even 0.25m, but they only create those for specific purposes, for example around river valleys for flood management.

Archaeologists have been using public lidar data for many years.  You may have seen TV programmes about the work of Dr Sarah Parcak(https://en.wikipedia.org/wiki/Sarah_Parcak/).  She has used public lidar data to discover previously unknown archaeological sites in the Middle East and elsewhere, doing a lot of the work from her office in the USA.  

It's now becoming possible to mount a lidar unit on a drone and run your own survey.  That widens the market and brings the prices down - £2,000 for a basic lidar unit rather than £100,000.  The expensive unit is much better, of course, more accurate and with much greater functionality, but the cheaper unit allows many more people to get in on the act.

This is comparable with something that's already happened in the music industry.  Back in the 1960's, recording equipment was expensive and only large record companies could afford studio time, so to get a record out, a musician had to be signed to a record label.  Now musicians can make their own recordings in their bedrooms and sell them independently, and this has revolutionised the music business.  Cheap Lidar will have a similar effect on mapping, construction and archaeology.

This means that Lidar is no longer a specialist subject.  Lots of ordinary people now have to get their heads around how it works, which is why I've set up this group.