Map Ref Question

[Drumelzier]

I'm getting bit confused with a reference on an Map of Ypres : 28.K.32.C.4.5

On re-checking this,it's the C.4.5 that's got me.

In the example on the Great War website it has sections a,b,c, & d each being 500 sq yards.

"Within each of the a, b, c and d sub-section the square was marked with notches for each 100 yard marker. The co-ordinates reference within a sub-section would normally be given as two numerical digits, such as 2.3. Within a 500 yard sub-section the first point would be located at 200 yards to the east and the second point 300 yards to the north."

However, in the example below it looks like the 500 yard squares are broken down into 50 yard markers not 100 yard markers.

I've probably not explained this very well but if someone understands what I'm trying to say can they please confirm my thinking or disagree and explain where I am going wrong ?

Thanks

[CROONAERT]

I know what you mean... the 'notches' in each square do, indeed, represent 50 yds on British 1:2,500, 1:5,000 ,1:10,000 and 1:20,000 scale trench maps.

Co-ordinates are not necessarily given as two digits such as mentioned on the website you quote either. 4 digits (and even 6) dependant on the map scale used and the degree of accuracy required are just as commonly encountered

Dave.

[Dai Bach y Sowldiwr]

Yes. You are correct.

The digits are one-tenths of the small square's length.

As you have figured out yourself, it narrows the location down to a square 50 yds by 50 yds.

Double digit co-ordinates (say if your example was 28.K.32.C.40.50) represent a degree of accuracy of one hundreth of the small square's length.

That would give a square with 5 yard sides.

I'm sure you're familiar with the Great War British Trench Map Coordinates Converter at :

http://rdf.muninn-project.org/TrenchCoordinates.html

If not, it's a great way of seeing where a co-ordinate relates to.

Enter the map co-ordinates as you have written them above,- 28.K.32.C.4.5 including the map Sheet no (28 in this case) into the search box, and it will give you the modern day Google map of that co-ordinate.

You don't have to put in the whole co-ordinate.

You can just put in 28.K for an overview of the area (6000 x 6000 yards), 28.K.32 for more precision (1000 x 1000 yds), or to be more precise again 28.K.32.C (500 x 500yds).

If you want more precision, you must put in the two x and y co-ordinate numbers, separated by a full stop.

It won't work if you just put in one number at this point.

Apparantely it doesn't work in Internet Explorer.

[EDWARD1]

How to Find a Trench Map Reference

Example of a 500 yard square to illustrate the map reference of Sheet 28.NW4.I.12.b.5.9.

If you are looking at War Diaries to find out the location of a unit on the battlefield and you find references to Trench Map co-ordinates, this is an example of how to find the Trench Map reference.

The section of Trench Map shown here shows Lake Farm to the east of Ypres, north of Bellewaerde Lake and the Menin Road (see square 12 on the Trench Map at the top of this page).

The Trench Map reference for Lake Farm is:

• Map 28.I.12.b.5.9

1. On Map Sheet 28 the 6,000 yard square is “I” = 28.I

The 1,000 yard square within “I” is square number 12 = 28.I.12

The 500 yard quarter sub-section square is “b” = 28.I.12.b

Using the “notches” marked on the top and right side of the “b” square, Lake Farm lies on the co-ordinates of 100 yards east at 5, and 900 yards north at 9 = 28.I.12.b.5.9

Lake Farm was likely named because of its close proximity to the Bellewaerde Lake. Lake Farm Spur can be seen as a spur off a narrow-gauge field railway line running to the farm.

The above example from the Great War site is equally confusing. I have highlighted in red the confusing figures. The the 5 of I12b5.9 is 5/10ths of the square 250yds East and the 9 is 9/10ths or 450 yds North

Eddie

[Drumelzier]

I know what you mean... the 'notches' in each square do, indeed, represent 50 yds on British 1:2,500, 1:5,000 ,1:10,000 and 1:20,000 scale trench maps.

Co-ordinates are not necessarily given as two digits such as mentioned on the website you quote either. 4 digits (and even 6) dependant on the map scale used and the degree of accuracy required are just as commonly encountered

Dave.

Thanks Dave.

[Drumelzier]

Yes. You are correct.

The digits are one-tenths of the small square's length.

As you have figured out yourself, it narrows the location down to a square 50 yds by 50 yds.

Double digit co-ordinates (say if your example was 28.K.32.C.40.50) represent a degree of accuracy of one hundreth of the small square's length.

That would give a square with 5 yard sides.

I'm sure you're familiar with the Great War British Trench Map Coordinates Converter at :

http://rdf.muninn-project.org/TrenchCoordinates.html

If not, it's a great way of seeing where a co-ordinate relates to.

Enter the map co-ordinates as you have written them above,- 28.K.32.C.4.5 including the map Sheet no (28 in this case) into the search box, and it will give you the modern day Google map of that co-ordinate.

You don't have to put in the whole co-ordinate.

You can just put in 28.K for an overview of the area (6000 x 6000 yards), 28.K.32 for more precision (1000 x 1000 yds), or to be more precise again 28.K.32.C (500 x 500yds).

If you want more precision, you must put in the two x and y co-ordinate numbers, separated by a full stop.

It won't work if you just put in one number at this point.

Apparantely it doesn't work in Internet Explorer.

Thanks Dai,

Yes, I have used the convertor and it gave more or less the location I worked out using the old maps, I was happy I had the correct location (it was a grave) but starting doubting it after re-reading everything and getting confused by the 10 x 100 yard markers on a 500 sq yard grid.

[Drumelzier]

How to Find a Trench Map Reference

Example of a 500 yard square to illustrate the map reference of Sheet 28.NW4.I.12.b.5.9.

If you are looking at War Diaries to find out the location of a unit on the battlefield and you find references to Trench Map co-ordinates, this is an example of how to find the Trench Map reference.

The section of Trench Map shown here shows Lake Farm to the east of Ypres, north of Bellewaerde Lake and the Menin Road (see square 12 on the Trench Map at the top of this page).

The Trench Map reference for Lake Farm is:

• Map 28.I.12.b.5.9

1. On Map Sheet 28 the 6,000 yard square is “I” = 28.I
2. The 1,000 yard square within “I” is square number 12 = 28.I.12
3. The 500 yard quarter sub-section square is “b” = 28.I.12.b
4. Using the “notches” marked on the top and right side of the “b” square, Lake Farm lies on the co-ordinates of 100 yards east at 5, and 900 yards north at 9 = 28.I.12.b.5.9

Lake Farm was likely named because of its close proximity to the Bellewaerde Lake. Lake Farm Spur can be seen as a spur off a narrow-gauge field railway line running to the farm.

The above example from the Great War site is equally confusing. I have highlighted in red the confusing figures. The the 5 of I12b5.9 is 5/10ths of the square 250yds East and the 9 is 9/10ths or 450 yds North

Eddie

Thanks Eddie, Yes, saw that example and the bits you highlighted seemed to double my confusion.

If I use my 4.5 co-ordinates as 4/10ths and 5/10ths it takes me to pretty much the same place as the convertor shows.