Finding trenches and craters using LiDAR

[Howard]

There have been a few threads on the forum about LiDAR but recent websites have opened up the possibility of using LiDAR free for the Great War.

If you have a look at the Earth Engine site, there are some useful results. The Canadian Memorial at Vimy shows a lot of craters, especially in the forested areas usually cordoned off to visitors.

Searching for Vimy Ridge Visitor Education Centre works. Looking at little further East there is Mont-Saint-Éloi with more detail.

The LiDAR used has a resolution of 1 metre meaning each pixel in the page is 1 metre wide so will not show detail finer than that. What is not obvious is why some results do not show much. An example of this on the Earth Engine is Beaumont-Hamel Newfoundland Memorial- the trenches do not show except in the south in the wooded area. That looks like a LiDAR processing error.

This LiDAR uses a Digital Terrain Model, DTM, in which trees and buildings have been stripped off in software to reveal the ground below. The data is processed using oblique returns when the laser can glimpse between the trees and see the ground.

Other areas with useful results are the Bois des Buttes, La Ville-aux-Bois-lès-Pontavert, the scene of the 2nd Devon’s famous action in May 1918 on the Aisne. Compare that with my crop marks article shown on TrenchMapper Help->Knowledge Centre->Crop marks- the first graphic is just south of the Bois des Buttes.

In contrast, the excavated trenches at La Main de Massiges do not show at all.

This means that although some useful information can be had using 1M LiDAR, finer resolution is better. Sadly is it currently hard to come by. The graphic here is the Hohenzollern Redoubt with 1917 front lines, (North West of Hulluch). This is using 25cm LiDAR but as yet, the French government have only released 25cm data for a tiny part of France. More promised in the winter of 2024/25. The image of the same place on the Earth Engine site does not show very much, not even the craters at the top of the graphic.

Howard

 

 

[Open Bolt]

Thanks Howard, very interesting. Yes, I was able to see that corner of trenches at Beaumont Hamel but nothing else yet...

[Howard]

There is much to be found by exploring LiDAR. Belgium publishes 25cm LiDAR for Flanders, sadly such is the political spilt in Belgium, the data for Wallonia is on a separate and very different site.

If you open the Flanders site, under Achtergrondkaarten there are a number of views depending on the processing of the data.

GRB is a simple map to allow navigation, one of the most interesting as DHMV II Hillshade 25cm. It is a DTM or Digital Terrain Model whereas DHMV II SolarIrr 25CM is a DSM Digital Surface Model with the trees and buildings left in place.

Here as some simple screen grabs of Hill 60, Sanctuary Wood, Hooge and Bellewaerde and some of the Messines mine craters.

Howard

 

 

 

 

[mjh]

Thank you Howard for sharing these great resources. I'd come across the Belgium site before, and had used it to see the cratered environments around Mt Kemmel, hidden by trees.

The French website has really opened up just how many ww1 trenches and cratered ground still exist, and I have pretty much followed the areas of la zone rouge, to see where remains are now visible using LIDAR. There are huge areas of forests which were of course planted in the destroyed regions, over ground that was never cultivated. A great example can be seen around the craonne area.

I was surprised to see that the forested areas around Verdun, did not show anything up however.

Best wishes

Michael

[Howard]

9 minutes ago, mjh said:

Thank you Howard for sharing these great resources. I'd come across the Belgium site before, and had used it to see the cratered environments around Mt Kemmel, hidden by trees.

The French website has really opened up just how many ww1 trenches and cratered ground still exist, and I have pretty much followed the areas of la zone rouge, to see where remains are now visible using LIDAR. There are huge areas of forests which were of course planted in the destroyed regions, over ground that was never cultivated. A great example can be seen around the craonne area.

I was surprised to see that the forested areas around Verdun, did not show anything up however.

Best wishes

Michael

Yes, I was also surprised. The problem is the quality of the French LiDAR, even at Newfoundland Park they don't show except in the forest- over processed. I hope their extension to the 25cm resolution area will be online soon- they say 2024/25. 1m does not seem enough. I hope they take note of the Belgian efforts- far better.

It is all worth keeping an eye on, it will be very useful when better resolution data comes online.

Howard

[KernelPanic]

On 29/07/2024 at 06:37, Howard said:

There is much to be found by exploring LiDAR. Belgium publishes 25cm LiDAR for Flanders, sadly such is the political spilt in Belgium, the data for Wallonia is on a separate and very different site.

If you open the Flanders site, under Achtergrondkaarten there are a number of views depending on the processing of the data.

GRB is a simple map to allow navigation, one of the most interesting as DHMV II Hillshade 25cm. It is a DTM or Digital Terrain Model whereas DHMV II SolarIrr 25CM is a DSM Digital Surface Model with the trees and buildings left in place.

Here as some simple screen grabs of Hill 60, Sanctuary Wood, Hooge and Bellewaerde and some of the Messines mine craters.

Howard

Howard,

Thanks for pointing out the 25cm LIDAR for Flanders.  It's a fascinating resource to explore.  I suppose an obvious question is whether the data could be incorporated into Trenchmapper?  Overlaying Great War era maps onto the LIDAR images would open up a whole new view of what survives in today's landscape..

[Howard]

We do plan that for Phase 3 along with other new features. I agree that it would open all sorts of new lines of interest.

Howard

[KernelPanic]

30 minutes ago, Howard said:

We do plan that for Phase 3 along with other new features. I agree that it would open all sorts of new lines of interest.

Howard

Thanks. The efforts of the TM team make it a truly spectacular resource.

[Howard]

Thank you for that, good to know we are appreciated. It is a huge project involving 50+ volunteers. I passed on your comment to the team.

Howard

[mjh]

I second Kernel's sentiments Howard. I have really enjoyed utilising the trenchmapper features, to follow my great uncle's movements arounds Ypres in 1917/1918. Please also pass my appreciation onto your team from myself.

Michael

Edited 14 August by mjh
spelling mistake