How do you find the minutes and seconds of a country's position?

Question

I notice positions have the number of degrees (latitude and longitude) as well as the minutes and seconds of each point. What does that mean and how do you calculate minutes and seconds of a country?Thank you.

Answer 1

It is not minutes or seconds of the country. These are too minute and a country is very large. Lines of latitude or longitude are not found on ground. Further they get subdivided, as each degree into 60 minutes and each minute into 60 seconds. Though not drawn on maps you can imagine them as 60 minute lines between consecutive lines differing in 1 degree. 1 degree difference in latitude corresponds to 60 nautical miles of 6080 feet each. That is each minute difference corresponds to 1 nautical mile (1.15 statute mile that we normally mean, or 1853 2/3 meters) or 6080feet. If differing by 1second, it corresponds to 101 1/3 feet.

Difference between successive 1 degree longitudes has the same value as above if on Equator (latitude 0 d). But when we move away from it to a latitude (call it 'phi') the distance gets reduced by a factor of 'cos (phi)'. Sine phi=0 at Equator, cos 0=1 and there is no reduction. At poles, phi=90 d, cos 90=0 and so there is no distance between longitude lines (they all converge to a point).

All these are mathematical abstractions for the purpose of knowing your position and with relation to others whose positions are similarly known. So, you won't find them on ground.

You can know lat/long of a place. First locate 'Pole star' and accurately measure its elevation angle above the plane of horizon and that angle is the 'lat' of that spot. To fix the plane of 'horizon', check it with spirit level; when it is same through out then you can say it is the horizon.

For 'long' accurately time the moment when the sun is on the 'principal (noon) meridien'. This can be done by observing the shadow of a straight rod planted in ground, its verticality checked by a plumb bob. When the shadow is exactly North-South it indicates Sun's transit of principal meridien. From the local news (Radio) or TV channel know the local (time zones like GMT, IST, EST, PT, etc) 'noon' (1200 hrs) and compute the difference in time  from the spot Sun's transit. Normally local time zones are set at 15 d longitude intervals. If the sun's transit at that spot is earlier add 1 degree to that standard (time zone), for every 4 minutes and 1 minute of arc every 4 seconds. If your spot has noon later,  subtract.

Answer 2

Latitude and longitude are like hours with 60 minutes (or intervals) in between.  The 60 minutes can further be divided into 60 seconds for better accuracy.   It is the same format as a clock.  Only the British could invent such a confusing  system.

Answer 3

The globe is divided into a grid system for pinpoint location in degrees,minutes and seconds.

Latitude East/West and longitude North/South.

Google Earth gives pinpoint location on satelite images.

Answer 4

Minutes and seconds are merely a more precise measurement of latitude and longitude.  "80 degrees" and "80 degrees, 5 minutes, 104 seconds" is kind of like the difference between "I'm 5 feet tall" and "I'm 5 feet, 7 and 14/100ths inches tall".  

You can't calculate minutes and seconds of latitude/longitude for most countries because they span multiple minutes and seconds.  Only for the very smallest countries (e.g. Vatican City, San Marino, Monaco) would a calculation of latitude/longitude in a single minute designation be useful at all.  For example, you could possibly say Monaco is at longitude 7 degrees 25 minutes; but even that would only be fairly accurate for about half the country (the other half would be better described at 7 degrees 26 minutes).  See first link for a map of what I'm talking about.  See second link for a map of the Vatican providing latitude and longitude down to the seconds degree of precision.