Mapping Electromagnetic Field

In 2018 I gave a talk on mobile mapping technology at Electromagnetic Field, a festival held in Eastnor Deer Park.

As part of this talk I had most of the site scanned by my then-employer’s scanning truck. This page contains links to the data and information on how to use it.

Collection Equipment

The system which collected this data was a Rigel VUX-1HA scanner and a FLIR Ladybug5 camera (for RGB).

Caveats

LiDAR data is sometimes a pain to work with. Even with the best kit in the world, and a bunch of time spent processing, without control points and lots of manual marrying up of points in overlapping passes of the scanner, there’s noise and variation in the output. This isn’t a project that was done for professional use or to “proper” standards – I’ve had no such time in preparing this in my evenings, and so this dataset is presented as a “best effort” dataset, likely riddled with all sorts of errors and inaccuracies that we wouldn’t usually accept and which professional users may sneer at.

In absolute terms the x/y accuracy of this dataset is pretty good, and an upper bound of 5cm RMS error from OSGB36 (the British National Grid) can be expected throughout most of the scan. Within the scanner output, the accuracy is around 3mm between points – but only within the same pass. This dataset contains multiple overlapping and automatically aligned passes (you can see these as point source ID in the LAS file), and so there are some errors and anomalies. On top of this, the colour in this dataset comes from the overlaying of images on the points, using a calibration file and alignment – and I know the alignment I used wasn’t great. And the drivers didn’t go down the middle of the campsite, so there’s a bit of a void there. So, expectations set!

Scale and Data

The dataset available is a 92 million point dataset, generated by decimating a 1 billion point dataset produced from the initial scan sampled on a 5mm grid.

The dataset is a LAS 1.4 file, georeferenced to the UK National Grid, OSGB36 (OSTN15). There are simple classifications, intensity data (infrared return brightness), point count classification, and RGB data for each point.

Download and Viewing

You can view the scan in Potree here in most browsers.

The LAS file (3.2GB) can be downloaded here.

License

As the creator of this dataset, I license this dataset under a Creative Commons BY-SA license. The dataset may be used for any purpose, so long as it is attributed in some way and any derivative works are shared alike.

Eastnor Park LiDAR Survey is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.