Grid references

**MikeO** · 28-05-2012, 15:07

I have a full listing of the ww2 airfield decoy sites. I don't think this ever has been included in AR but stand ready to be corrected. As for the locations, there are 1940s Military Grid references. I wonder if anyone knows how to convert those into modern day NGRs?

**AiXAdmin** · 28-05-2012, 15:58

If nobody pitches up with a suitable converter I may be able to help... I wrote a little software app to do these types of map conversions. I may be able to incorporate such a conversion for batch processing.
Please let me have a few sample entries... PM for an email address.

Cheers
Dave

**David Thompson** · 28-05-2012, 16:48

I'm pretty sure we have had this question on the forum before and Carnaby may have the answer ?

**tigger** · 28-05-2012, 16:50

Steve's extended DoB google earth overlay already has those listed by Dobinson.
Easy enough to extract those with co-ordinates

**a10694** · 28-05-2012, 18:11

I've always found the DoB references, and Dobinsons, to be plus/minus a field or two. I've always debated as to what they are the reference of - bunker, centre of decoy site, SW corner of.....

I know from my own experiences that certainly some of the sites do not show at all on NMR aerial photos, so any location cannot be truly accurate for those.

**PNK** · 28-05-2012, 18:15

I always use this site http://www.fieldenmaps.info/cconv/cconv_gb.html

As long as you have the wartime two letter prefix. Accuracy depends on the number of numbers. Normally the result in the rough area but not the exact location.

**MikeO** · 28-05-2012, 23:02

Much appreciate responses to my question. I will set out a few examples of what I have and perhaps we can see whether a translation to current NGRs is possible.

Site No 12b was Kilham, a decoy fror Driffield and the listed grid reference is 28/557828.

Site No 26 was N. Tuddenham, a decoy for Swanton Morley grid reference 66/493317.

Site No 121 was Marsh Chapel, the decoy for Donna Nook, grid reference 40/871192.

All these from an August 1942 listing

**MikeO** · 28-05-2012, 23:12

Should perhaps add that the references are as per the one inch OS maps and I imagine the first two numbers indicate the sheet number in that series.

**tigger** · 28-05-2012, 23:47

Originally Posted by a10694

I've always found the DoB references, and Dobinsons, to be plus/minus a field or two. I've always debated as to what they are the reference of - bunker, centre of decoy site, SW corner of.....

I know from my own experiences that certainly some of the sites do not show at all on NMR aerial photos, so any location cannot be truly accurate for those.

I suspect the figures quoted being a field or two out is probably accurate enough given the scarcity of remains. Some quoted figures seem to be a nominal centre, some seem to be the bunker and some don't seem to relate to anything (in the sense that nothing can be found near them). The control bunkers were sometimes quite distant from the actual fields used (eg. Betchton).
Will be interesting to see if the references MikeO has are actually any better than the ones Dobinson uses (which must have come from a similar source)...but how will we actually know!

On the subject of conversions, I have found 'fieldenmaps.info' to have some large errors on some conversions.

**PNK** · 29-05-2012, 08:47

Most converters seem to have errors but I think they tend to be in certain areas where the "rules" do not work correctly.

There was a one inch map sheet guide on the internet at one time and I used to overlay it over the wartime grid uk map to get the two letter prefix. A bit hit and miss where they overlap but you can usually deduce where the correct location was.