I have been given a spreadsheet containing Degrees Minutes Seconds coordinates in the format 'DD MM SSS' (including the spaces). I've used the DMS - DD formula ‘DD = (Seconds/3600) + (Minutes/60) + Degrees' to convert the DMS values to DD. I have also used the Convert Coordinate Notation tool in ArcMap. Both methods agree that my DMS of 53° 47’ 985” = 54.05694. This would seem to be because the seconds contain three digits when they should contain only two. Does anyone have any ideas as to how this could have arisen? I'm now thinking that what I have is in fact Degrees, Minutes, Decimal Seconds.