Every location on earth has a global address which is given as two numbers (latitude and longitude) called coordinates. Basically, latitude and longitude are the units that represent the coordinates at geographic coordinate system.
Coordinates can be represented in:
- Degrees, Minutes and Seconds
DDD° MM' SS.S"
32° 18' 23.1" N 122° 36' 52.5" W - Degrees and Decimal Minutes
DDD° MM.MMM'
32° 18.385' N 122° 36.875' W - Decimal Degrees
DDD.DDDDD°
32.30642° N 122.61458° W
or +32.30642, -122.61458
Today was the day I recognized that I have some troubles in identifying which is latitude or longitude when they are represented in Decimal Degrees!!
It may not seem a big problem, but it is for me when I need to work with coordinates and import them from a spreadsheet to a Geographic Information Software (GIS).
I know the cardinal points, I know longitude is related with East-West axis, and latitude with the North-South axis, I have learned x,y graphs on mathematics classes, and I also recognize the numbers of a coordinate point located somewhere in Portugal (e,g, 38.711406, -9.195174), but...
"Which one is the X? Latitude or Longitude?" That 's was the problem!!
(I know the basic information, but didn't know how to put it together)
I used to have a 50% chance of getting it right, but today was time to learn once and for all!!
I search a bit and find this very elucidative video "Longitude and latitude explained" by the Australian National Maritime Museum!!
Now I know:
- Latitude measures how far north or south a point is from the Equator
- Longitude measures how far east or west a point is from a specific meridian. Nowadays it is used Prime Meridian, a zero degrees longitude, which runs through the British Royal Observatory in Greenwich England.
If longitude is related to east or west distance from the Prime Meridian, that must be the X coordinate, and latitude is the Y coordinate!!
I will also use a mnemonic trick for lonGitude....I will imagine the "x" letter in the place of "g": "lonXitude" and in my mind, I will keep understanding the word longitude!!