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Help With Grid Inquest

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I am finding this program a little difficult to use. My main problem is that, when importing OSGB co-ords, there seems to be no method of inputting the letters in front of the number (eg SP1234567891). I know from using Mimee that these letters can be replaced by numbers, but I have no idea how to determine what the number might be for a particular letter code.


Advice would be much appreciated!

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Ah I know the answer but can't think of the words to write it; I'm pulling my hair out here <_< It's all to do with the Letter squares being 100KM across and down and the initial datum is somewhere in the North East above Scotland. You can calculate the value of the leading figure from the letters. E.G. SJ S is the northing and J the Easting and that equates to a number of meters form the datum point. But you.ll have to look the rest up on the OS website. So SJ1234567890 might look like this 312345 367890

Edited by Moote
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Grid InQuest uses national grid coordinates, not NGR.


If you want to batch process NGRs with Grid InQuest you will have to first process your NGRs with third party software into full coordinates.

Thanks for that info.


I must admit that I do find GridInquest a bit difficult - maybe I need training in this area. I get so confused with all the different ways of expressing locations. :unsure:

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For a map of the grid squares with the 100km distances marked, see my avatar!


For an explanation (please excuse me if it's too simple, but there's always someone who doesn't know);


Using NGR,

A 10 figure grid reference is used describes a map location to the nearest metre, but 10 figures only allows a maximum distance of 100km (well, 99,999 metres). To keep references unique, they are preceded by the grid square letters (such as SP or SU etc), as an example, Romsey town centre is at SU 35221 21211. Basicalliy, this says it's 35.221km from the western edge of the SU square and 21.211km from the southern edge.


Using National Grid (as in GridInquest),

A 12 figure grid reference describes a location to the nearest metre, measured from a location to the south west of the Scilly Isles, in this case, Romsey is at 435221,121211.

I think that these go up to 13 digits when you get up to the Shetland Isles, but I've never been that far north.


To convert between the two, feel free to use my avatar. There's also very useful guides to Co-ordinate systems on the OS website. Also, if you look at the corner of your OS 1:50k or 1:25k map, you'll see that the eastings and northings for the corner have the 100km numbers slightly smaller than the km square numbers, and the map key has an example of how the NGR system works.


Hope this helps,




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wouldn't it have been easier if the earth had actually been flat?

Yes. That's why we use the Transverse Mercator Grid, such as Ordnance Survey coordinates.


TMG effectively flattens the Earth, within the area of coverage.


The complication of NGR is unfortunate, but is a legacy of the old days when cartographers were obliged on a local scale to work from the part to the whole instead of following their trained policy of working from the whole to the part.


Unfortunately, we seem to be stuck with the wretched and confusing arbitrary NGR.

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