Drone mapping and modelling an Iron Age landscape.

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Drone mapping within an Iron Age Settlement.

 

Maps.

It has to be said, here at clearskyimaging we do love a good map or two! So much so that we have undertaken courses in mapping and photogrammetry with drones, and QGIS in order to present any mapping data we obtain for clients.

Being based in Shropshire, within the Welsh marches, we do have a fair bit of history too.
Here, we took the opportunity to investigate a local Iron Age hillfort, Nordy Bank.

Nordy Bank from a Cassini Historical map from 1832-6, drone photography uk
Nordy Bank from a Cassini Historical map from 1832-6
Nordy Bank from a Cassini historical map from 1920/1,drone photography uk
Nordy Bank from a Cassini historical map from 1920/1

Permission was sought, and granted, from the Parish Council to fly from the hill. Although the weather wasn’t really suitable for a few weeks, being autumn, very windy, and very wet! 
Since the owners of the sheep which normally graze the land had them away for a few weeks, to be ‘tupped’ we took the opportunity to visit and hopefully complete the task.

Preparation.

We planned the flight prior to travelling, inputting the flight into ‘Map Pilot’ as we were considering utilising ‘Maps Made easy’ to compute, and display the results. Adjusting the flight so that it suggested that it would take less than 3 batteries in our Phantom 4 pro, the drone that we utilise mainly, for mapping.

It was decided to take along our Mavic Pro drone too, to take some none mapping related images, and possibly videos too. It became clear later that it was fortunate that we did!

Getting to the site,we had intended to use the road to the transmitter station to park close to the edge of the fort… No joy. Permission was needed to take a vehicle on the track, and we didn’t have it. So down to the small ‘car park’ at the bottom of the hill it was.

The ‘sack truck’ was loaded up with the Phantom 4, and Mavic, in their Peli cases and the necessary parts of the safety equipment for the flight and the path to the top taken.

It was rather steep! Luckily the Peli cases saved the day on more than one occasion when the bungy cords slipped and deposited one or the other onto the ground.

After a while, we managed to get all the equipment safely to the top. Then set up the take off and landing point approximately half way between the extents we’d planned to fly.

This position was chosen in order to ensure that the flight was completely in Visual Line Of Sight, as per CAA regulations.

Drone mapping Nordy Bank, Drone Topographic Survey, Aerial Imaging, Shropshire
View from Nordy Bank

Flying the planned route.

After ensuring that all was OK with the Phantom, taking off and hovering to make sure that all controls were operational, the planned flight was uploaded and initiated.

It became clear that the planned for 3 battery flight would not be sufficient as the drone returned around 20% of the way through with a ‘low battery’ alert.

As the third battery alerted, and the drone returned to the Landing Point, a decision was made to utilise the Mavic Pro to complete the flight. It wasn’t known, at this point, how the different sensors would affect the results, or even if the software used would accept the different sizes/focal lengths etc.

Thankfully, 2 and a bit batteries were sufficient!, which allowed time for a couple of quick videos and photos of the surrounding area.

Then it was time to pack up. We took a route back down that was less steep than the route up!

Producing the outputs from the images collected.

Back at base, the images were uploaded to Maps Made Easy. They were rejected immediately as they weren’t all from the same drone/sensor.

What to do?

OpenDroneMap to the rescue! The data was input without a problem, thankfully. some 530-odd images were stitched in the application, producing the desired outputs.

 

Drone mapping, ortho photo of Nordy Bank, Drone Topographic Survey, Aerial Imaging, Shropshire
Ortho photo of Nordy Bank from 530+ images
Drone map, a height map of Nordy Bank, Drone Topographic Survey, Aerial Imaging, Shropshire
Height map of Nordy Bank from 530+ images

A ‘fly around’ of the completed 3D model

Finally.

We are quite impressed that OpenDroneMap should accept images from2 different sensors on 2 different drones! It is also quite impressive that the differences between the imagery collected by both are negligible  in the final results.

It’s also easy to see that the sun appeared towards the end of the exercise, one side of the hill being bathed in sunlight!

We’ll be working further with the results in time, to produce outputs in conjunction with QGIS to provide the Parish Council with some formatted data and imagery.

If you’re interested in having mapping and/or modelling of an area of land please do feel free to contact us. We’d be pleased to discuss your needs

If old maps of the UK are of interest, we’d certainly recommend taking a look at  Cassini Maps, Hours of fun for mapping nerds!

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