Trench map Overlay

[towisuk]

I've been playing with the "Add Image Overlay" found on Google earth, and combining it with trench maps from the "Linesman" package.

I seem to get a spot on N-S alignment as seen with the SerHeb road, but the east-west alignment seems slightly out at the edges of the overlay, as seen by looking at the D919 that runs through Serre,(maybe something to do with the curvature of the earth)..... Still a useful little tool to see a general overlay of the trenches to what we are able to see on the ground today

regards

Tom

[Borden Battery]

Hello Tom

Very nice piece of work and something that I would very much like to see for a much wider range of maps and battles.

Borden Battery

[towisuk]

I think we can see from this overlay, that what is commonly taken to be the front line trench just inside Sheffield Memorial Park boundary is no such thing, it is, as Dave (Croonaert) pointed out in an earlier topic, most likely a drainage ditch...The front line trench on the map being several yards outside the Park area at the south west end...

Tom

[dfaulder]

I've been playing with the "Add Image Overlay" found on Google earth, and combining it with trench maps from the "Linesman" package.

I seem to get a spot on N-S alignment as seen with the SerHeb road, but the east-west alignment seems slightly out at the edges of the overlay, as seen by looking at the D919 that runs through Serre,(maybe something to do with the curvature of the earth)..... Still a useful little tool to see a general overlay of the trenches to what we are able to see on the ground today

regards

Tom

This is probably due (as has been mentioned elsewhere) to the two sources using different projections.

When adding an overlay, you can skew it, stretch, squash and rotate it (experiment with grabbing and dragging the handles on the image) which means for small extracts you can get an almost exact match. See: http://earth.google....n&answer=148099

David

[towisuk]

Many thanks for that David, I'll have a few more plays with it and see if I can get a better match...I've been using co-ordinates which I set up, both in Google Earth and "Linesman" to match up the images..

regards

Tom

[Nigel Marshall]

As a new Linesman user and an infrequent Google Earth user, this is fascinating.

I will have to find some time to have a play.

Cheers,

Nigel

[Smithmaps]

Hi

I think I answered this problem on a recent topic

Here

Google Maps are in an entirely different projection to Trench maps and will never overlay accurately.

LinesMan displays each map in it's original projection, and transforms any overlay between each map. Thus allowing accurate location of features between old and modern.

Still all good fun.

Guy

[towisuk]

Thanks for the link Guy, as you say all good fun, but it does give one the area where the trench was when "in the field" without a PDA. When I was at Sheffield Park

the position of the front line trench being well outside the park boundary on my PDA troubled me, like many others I was under the impression that the depression just inside the gate was the front line trench. But it's possible see, using the overlay system that this is more likely a drainage ditch and not a trench, I had used the "Sync" on "Linesman" to draw the line of the trench from a map onto an adjacent aerial shot which showed this(an excellent tool by the way). I've since learnt to manouver the Google Overlay to match the map to known landarks and am more than happy with the results....as I am with the "Linesman" package, you are responsible for my weight gain, I spend hours in front of the pc playing with the maps mate!!

regards

Tom

[bmac]

Having played around some years ago (pre-Linesman) with overlays onto Blue Series maps for the whole Somme front line I find it interesting that the problem I had with alignment at Serre is the same as yours. I could get either the north west running roads/tracks to align or the NE running roads/tracks. Never both. Can't show you as the file is 9Mbs and in a format I currently cannot edit. I am sure there is a perfectly good reason why my two sets of maps don't line up accurately. Do they on Linesman? I am intrigued as I was recently at Gommecourt with someone who had Linesman on a PDA. The results clearly showed a major feature (Nameless/Bock Farm) to be on the wrong side of the Gommecourt to Pisieux road which is odd. Were the original maps unreliable or were some of these roads changed in subtle but significant ways after the war?

[towisuk]

Hi bmac, I find the "Linesman" maps and aerials to match as they should. But this was a little exercise in combining trench maps in "Linesman", where you are able to read the map Co-ordinates accurately as you move the mouse over the map, with map co-ordinates on Google Earth. As Guy has explained in the link in his post above it's not as simple as that, but certainly on small areas it works very well for my purposes. On larger areas such as the Serre map in my first post, you can see the innacuracies in some roads in the overlay, but thanks to Davids link in post #4 in this topic, I've been able to manouver the edges of the maps to give a far better match-up in Google earth overlays.

Sitting here in the warm, with the rain and wind swirling around the buildings outside, this is a pleasant way to spend a few hours. Doesn't do much for my waistline..but that was a lost cause ages ago!

regards

Tom

ps... maybe the farm you refer to was rebuilt following the war, on the other side of the road, just as Mouqet farm at Thiepval was after the armistice

[bmac]

Nameless Farm no longer exists. According to the person who had the PDA it was placed north of the road on the Blue Series overlays on Linesman. It was to the south of the road in 1916.

[CROONAERT]

According to the person who had the PDA it was placed north of the road on the Blue Series overlays on Linesman. It was to the south of the road in 1916.

I presume here that the person with the PDA was using a 1916 map on his PDA as a comparison with the IGN map? If they'd used a 1918 map, they'd have found themselves in the correct position (most editions of the pre-1917 British maps are slightly 'off' for that particular area).

Dave.

[bmac]

I assume 1916 as the subject of the tour was the 1st July attack. How widespread was the 'offness'? Did it impact on the Serre area too? I guess we are talking about the location being 50-75 yards off on the combination of the 16 map and the Blue Series. Also, why would this not interfere with my overlays which had the farm correctly located (i.e. 16 map onto a Blue Series with very little tweaking, and that mainly at the edges)?

[CROONAERT]

... How widespread was the 'offness'? Did it impact on the Serre area too?

basically, the whole front, so, yes, Serre too. It doesn't seem as bad for British held territory (unsurprisingly) though. It all depends on the edition of the map though... some appear to be spot on.

I guess we are talking about the location being 50-75 yards off on the combination of the 16 map and the Blue Series. Also, why would this not interfere with my overlays which had the farm correctly located (i.e. 16 map onto a Blue Series with very little tweaking, and that mainly at the edges)?

I didn't think it was going to be as bad as 50-75 yds but I just did a random check of 1915/16 maps and was actually quite surprised at the margins of error on some editions (see attached image where the circles represent the farm buildings on different editions). As to why yours overlaid correctly... Maybe you were lucky and actually used the more accurate editions? i don't know really!

[CROONAERT]

Did it impact on the Serre area too?

Differing frontlines in front of the apostles copses from 3 different 1916 edition trenchmaps...

[bmac]

Boy, not insignificant changes if one is trying to understand the battlefield in detail. On the Nameless Farm location (relative to the modern road and assuming it pursues the same track as the 16 one) then the most southerly one is correct. At Serre those variations have the potential for significant changes. I would guess that the one of the two westerly lines for the German front is correct as the area of scrub (which no longer exists) through which it runs at the centre/bottom was the site of a mine crater. I have the central German line on my overlays and the British line running slightly east of the track at the southern end. These seem like minor quibbles until you get to see the subtleties of the terrain and the way that defences exploited them. Looks like we will never know for certain around this area.

[Robert Dunlop]

Thanks, Croonaert. You have illustrated the point very well!

Robert

[rjhorritt]

Good Afternoon to all, I have just registered to this forum and was interested to see this topic, I have the Linesman series of trench maps and for the life of me cannot get them to overlay to Google Earth like this,when I got the Linesman this is the sort of thing that I wanted to do initially, is there a simple solution and for example which way do you start eg with google and put the map over?, I tried this but found that Google does not accept mmo (linesman-memorymap) files/ help appreciated please. My particular region of interest is Somme/High Wood and immediate surrounds.

[davidmichaeljarvis]

How about this one of John copse

[towisuk]

Good Afternoon to all, I have just registered to this forum and was interested to see this topic, I have the Linesman series of trench maps and for the life of me cannot get them to overlay to Google Earth like this,when I got the Linesman this is the sort of thing that I wanted to do initially, is there a simple solution and for example which way do you start eg with google and put the map over?, I tried this but found that Google does not accept mmo (linesman-memorymap) files/ help appreciated please. My particular region of interest is Somme/High Wood and immediate surrounds.

Welcome to the forum, if you look through some past topics regarding map overlays using Google earth, I'm sure you will find something that will be of help to you.

And no doubt some of the other members who also post maps and overlays will be along soon to help you out.....

regards, and welcome once again

Tom

[horrocks]

The John Copse aerial/GE overlay above is extraordinary. When was it taken? The artillery damage to the German lines, indeed the overall cratering, is very light. If this is post 25th-1st July, it is little surprise that the garrison was so effective on 1st July.

Forgive me for not quite keeping up, but is the conclusion to the earlier discussion on this thread that the trench line along the front of Sheffield Park is wrong and is a drainage ditch, or is there some variation in the Linesman/Google Earth setup that simply gives the impression of a different alignment, and that the Sheffield Trench is in fact correct?

A few years ago I actually wandered deeper into the Mark-Luke thicket, and the communication trenches (either or both) Central and Northern Avenues are very clear and deep. Didn't one of these lead pretty much directly into one of the unused (on July 1st) saps?

[davidmichaeljarvis]

If you google "serre" it will come up with several sites. The site for the picture above is "Serre @ 7.20am 1st July 1916. I believe that the photographs were taken by RFC on the morning of the 1st July 1916. There are 3 other similar photos which I have also overlayed but the above is the best by far. Dave

[horrocks]

If the photo really was taken at 7.20am on 1st July, it is barely surprising that these fields yield so many dud British shells, and that the German defense was so decisive. There is clearly some concentration of HE cratering on the German fire trench, and an area in opposite the copse where there is clear damage, but there seems to be no location where the trench is totally blown in, and the reserve and communication trenches appear virtually untouched - and all this after 6 days and nights of continuous barrage. I assume that the slightly darker areas in front and immediately behind the trench are evidence of shrapnel scoring, and that it might follow that the majority of the ordnance sent over, and which actually exploded, was shrapnel rather than HE.

I notice that there seems to be a secondary trench sytem just in front of the British main/fire trenches. Presumably this is a recently dug assault trench. If so, what was the true purpose of this system, because it cannot have served the that of getting the initial assault point out close to the German lines - it is barely a few feet in front of the exisiting fire trench?

Sorry if I am drifting off topic a little, but this is a real eye opener for me.

[rjhorritt]

Welcome to the forum, if you look through some past topics regarding map overlays using Google earth, I'm sure you will find something that will be of help to you.

And no doubt some of the other members who also post maps and overlays will be along soon to help you out.....

regards, and welcome once again

Tom

Tom

Several evenings later and still no nearer, can it be that hard ? What I wish to do is overlay a Linesman trench map to Google Earth or vice versa which is ever is easier I really need an idiots guide eg what to save files as and how to open them on the overlay I think I have over complicated things and confused myself Thanks.

[Ken Lees]

Hillfield,

What did you discover by searching through previous threads on the subject, as suggested earlier? Did anything help?