I've been provided with a dataset containing some coordinates, but I don't recognise the coordinate system used. They look like standard UTM coordinates but the values don't match up with what I expect, which are locations in Scotland, UK.

For example, a random record gives GIS_X as 349275.0 and GIS_Y as 636198.0. Using these coordinates along with zone 30, plugging these values into http://www.rcn.montana.edu/Resources/Converter.aspx results in WGS coordinates not far from the equator, which is evidently wrong.

The datasource is checked daily for various errors so I'm fairly certain the data provided to me is correct; any ideas for how these values might make sense, given the expected result?

1 Answer 1


The coordinates you have given above are very much in Scotland (Galashiels) if you assume they are in epsg 27700 (i.e. ordnance survey grid). It looks like someone or some process has entered the information in an unexpected coordinate system.

There is no way to "detect" the coordinates system. You could probably rule out a few by looking at max / min bounds, but usually it is provided as metadata with the file or in the database.

  • Yes, "detect" was probably a bit ambitous - unfortunately I'm just provided with a raw CSV with no documentation. Thank you for pointing me in the right direction :)
    – Graham
    Aug 13, 2018 at 18:07

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