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Learning to count

Publiée par chriscf le 17 août 2010 en English.

While examining the limits of the internal zones in UK waters, a recent Statutory Instrument defines one of the points on a boundary as being at longitude 02°42'95"W. Anyone know what I'm supposed to make of this? Other than the usual government incompetence, of course.

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Discussion

Commentaire de RichardB le 17 août 2010 à 22 h 43

I've seen the document for the Welsh border - and it has many points with greater than 60" - too many for it to be an isolated mistake. Perhaps they're not seconds of arc, but decimal minutes? In which case, your coord is 51º32.53' N, 2º42.95' W

Commentaire de RichardB le 17 août 2010 à 23 h 37

Right, they are in decimal minutes, and not seconds of arc. The reason I can tell is because most of the coordinates are also defined in SI 1999/762 - which defines the border in the Dee & Severn Estuaries. If you convert the coords in SI1999/762 from OSBG36->WGS84 - then the points lie extremely close to those from the latest document with decimal minutes - but much further away with seconds of arc.

Commentaire de chriscf le 18 août 2010 à 0 h 35

I have worked on that assumption for the Welsh points, and not on that assumption for the Scottish baseline (the points fit better as arcseconds than decimal minutes). However, I realize I may have accidentally used the decimal minute conversion for the Northern Ireland limits, so will probably need to reimport those (and redraw the lines).

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