PDA

View Full Version : OS Grid References



David Griffiths
10-26-2009, 06:44 AM
Hi

I have a small UK data file with OS Grid References atttached to each record. The grid references are held as an Easting (a 4 byte numeric field) and a Northing (a 5 byte numeric field). These are OS 100 metre easting and northings. I wish to map this data in Mappoint 2009 for Europe and create a series of Pushpins to mark each site. I see that Mappoint allows for this type data and has a single field called OS Grid Reference so when I concatenate my Easting and Northing I do not get much success. Does anyone know what format the software is expecting the OS Grid Reference field to be in?

davidb
10-26-2009, 08:30 AM
If you click on Find(binoculars symbol)/OS Grid there are examples of the 2 acceptable formats for OSGRs. In the numerical case it expects a 12 character reference (easting of 6 characters, northing of six characters). For example the OSGR of 10 Downing Street is 530067179949. The bottom left hand corner of the 100m square containing the address is 530000179900. So I think you will need to append zero's to the references you have and then concatenate. Remember also that for some OSGRs you have a zero as the first character so they need to be handled as strings.

HTH

David Griffiths
10-27-2009, 06:39 AM
Thank you for your help it was very useful to see the structure of the mappoint os grid references using find. I have been able to map my data more or less. OS UK 100 metre eastings have a range 548 to 6554. But the northings have a range 81 to 12136. In other words the distance between my most sourtherly northing and my most northerly northing is 1,200 kilometres - this seems to make sense. Because they are 100 metre references I need to add 00 to the end which makes my most northerly northing have a value 1213600. Mappoint is expecting a 6 digit value and this meant I had to discard a few northings where the value was in excess of 1000. You can't truncate. Other than that it was fine. Thank you once again

davidb
10-27-2009, 08:19 AM
I think that MapPoint will handle 13 character grid references. As far as I know they relate only to locations in the Orkney and Shetland Islands. For example MapPoint locates the Sullom Voe oil terminal at 4396881175316. Also when you say eastings have a range 548 to 6554 they actually have a range 0548 to 6554 etc. Anyway glad you've got things working.