I'm sure this is a really dumb question, but I often see gps coordinates described in the format XX.XX.XX (for example [Only registered and activated users can see links. ]), which confuses me because I can't tell if these are supposed to be DMS format or D.M format. Which are they? If it's supposed to be DMS, then shouldn't it be written XX XX' XX" and if it's D.M format then isn't missing a digit and shouldn't it be XX.XX.XXX?
The spherical coordinates are measured in latitude and longitude. These angles are
measured in degrees from the center of the earth to a point on the surface.
The latitude varies from the north pole (90) decreases to the Equator (0) and decreasing
further to the south pole (-90).
The longitude varies from the Greenwich meridian (0) growing towards the east to the
meridian opposite (180) and decreases towards the west to the same meridian opposite (-
Cartesian coordinates are based on a system of two orthogonal axes (x, y). The location
of a point is given by the intersection of the two values.
A coordinate might be written for example as 65° 32' 15".
Degrees can also be expressed as decimals: 65.5375,
degrees and decimal minutes: 65° 32.25'
So coordinates can be in these formats:
Degrees - coordinates expressed in decimal degrees [Only registered and activated users can see links. ]
GMM - coordinates expressed in degrees and decimal minutes
which can be abbreviated as DºM.M’ “Decimal minutes”, as it integrates the seconds information into the minutes of the coordinate
GMS - coordinates expressed in degrees, minutes and decimal seconds
degrees, minutes and seconds, and in this format a position can be writted as: 51º 12' 18.8? North and 0º 35' 07.8? West. You’ll sometimes see this format abbreviated as Dº M’ S” “Degree Minutes Seconds”, it is the longest format. The problem with such long formats is that its allows many places for errors and misunderstanding during communication.
UTM - coordinate expressed in UTM (east, north, zone and hemisphere)
Thanks. The problem that I was alluding to was that rather than expressing coordinates in the form of the examples you gave as 65° 32' 15" or 65.5375 or 65° 32.25', each of which I think clearly indicates the format being used, many people seem to mix and combine the way they express coordinates in a way that makes it confusing. Often, for example, they forego the use of any degree, minute or second symbols using only decimals instead, which would suggest that they are using a decimal only format, except that the coordinates will have 2 decimals rather than just one. Thus, for example, I might see 65.32.15 or 65.32.25, neither of which gives me any clue as to whether or not the format is D.M or D.M.S (the second decimal does make it clear that it's not just D). I come across this all the time when looking up marine coordinates and I'm always left scratching my head.