Map Basics – How to Read Latitude and Longitude

Latitude and Longitude. They’re at the core of map reading. Latitude and Longitude are imaginary lines which lay on the surface of the earth to form a matrix of coordinates. However, the question is, how to read it? Which one is which?

Here is a basic explanation, and an easy way to remember which is which… and, a recommendation for a top-of-the-line compass for map reading.

Image globes: geographyworldonline.com

Latitude lines are imaginary lines on the earth’s surface. Each line runs east and west around the globe. And each one represents a distance/location north or south of the Equator.

Lines of Latitude run parallel to the equator (east-west).

Remember LATITUDE by thinking of a LADDER (sounds similar). The rungs (steps) of a ladder going east-west…

The ladder has rungs which you climb to go up and down, similar to the lines of Latitude which go up and down across the circumference of the globe.

Latitude lines run east and west, but they tell you (they indicate locations on a map) how far up (North) or how far down (South).

The equator is Zero degrees. The poles are 90 degrees.

Image globes: geographyworldonline.com

Lines of Longitude run from pole to pole (north-south). They tell you the distance east or west from the ‘Prime Meridian’.

The Prime Meridian is Longitude Zero. It is a reference line from which longitude east and west are measured. It passes through Greenwich, England, the site of the Royal Greenwich Observatory (0 degrees).

Remember LONGITUDE by thinking of long, tall telephone poles (because Longitude lines run from pole to pole).

A top-of-the-line compass for map reading (with USGS MTM scales)

SUUNTO MC-2 Compass for Professionals and Hikers
(SUUNTO storefront on amzn)

Latitude – Longitude Grid

Lines of Latitude and Longitude come together to form a matrix, or grid.

Latitude and Longitude is a common grid system used for navigation. It will allow you to pinpoint your location with a high degree of accuracy.

Latitude is angular distance measured north and south of the Equator.

The Equator is 0 degrees.

As you go north of the equator, the Latitude increases all the way up to 90 degrees at the north pole.

If you go south of the equator, the Latitude increases all the way up to 90 degrees at the south pole.

In the northern hemisphere, the Latitude is always given in degrees North, and in the southern hemisphere it is given in degrees South.

Longitude works the same way. It is angular distance measured east and west of the Prime Meridian.

The prime meridian is 0 degrees Longitude.

As you go east from the prime meridian, the Longitude increases to 180 degrees.

As you go west from the prime meridian Longitude increases to 180 degrees.

In the eastern hemisphere the Longitude is given in degrees East, and in the western hemisphere it is given in degrees West.

DISTANCES – Degrees, Minutes, Seconds

At the equator, one degree of Latitude or Longitude represents approximately 70 statute miles (a statue mile is 5280 feet).

At higher Latitudes (further up or down from the equator), the distance of one degree of Longitude decreases. That’s because all those lines of longitude come closer together as they approach the north and south poles (see the images above for visualization).

However, Latitude stays the same because they are always equally spaced apart. Again, it’s easier to understand if you look at a globe with the lines drawn on it (see images above).

Degrees

When you’re talking about degrees of longitude and latitude, they are not accurate enough to find a precise location. At best, one degree of latitude and longitude would define a 70 miles squared area, which would be 4,900 square miles.

Minutes

To overcome this problem, 1 degree is divided further into 60 slices, or what they call 60′ (minutes).

So if 1 degree equals 70 miles, and one degree can be divided into 60′ (minutes), then 1′ (minute) equals 1.2 miles.

Dividing 1 degree into 60 slices, or what they call 60′ (minutes), allows finer accuracy of position.

Seconds

In some instances even more accuracy is needed… To do this we can divide 1′ (minute) into 60″ (seconds).

If 1′ (minute) equals 1.2 miles, and we can divide it into 60″ (seconds), then 1″ (second) equals 0.02 miles.

It may be worth memorizing the following numbers. It will help you to use latitude and longitude more effectively:

1° (degree) = 70 miles
1′ (minute) = 1.2 miles
1″ (second) = .02 miles

Example: Los Angeles
34° 3′ 8″ North
118° 14′ 34″ West

34 degrees 3 minutes 8 seconds North / 118 degrees 14 minutes 34 seconds West

The map shown above only shows the major degrees. However as you can see, even the coordinates 34° N / 118° W will enable you to sight fairly quickly on the map where Los Angeles is generally located. If we had a map which also indicated ‘minutes’, then you could narrow its location down to approximately a mile. If the map also showed “seconds”, then you could pinpoint the exact center down to approximately 100 feet.

Think of it as grids within grids… It’s just a matter of having the right map which overlays latitude and longitude down to the resolution that resolves for your purpose.

1. Romeo Charlie says:

Changes in Latitude, Changes in Attitude——-Jimmy Buffett

1. Good one – my attitude would certainly improve further south during the winter ;)

1. DoubleTap says:

Grass isn’t always greener. Born & raised in MA then moved further south. I miss the snowstorms, & cold. You can always add more layers, but you can only take off so many before the law gets involved :-)

1. Kulafarmer says:

DT
Same can be said the other way, have lived at lat 20ish for most o my life, i missed it when i was freezing my arse off framing homes in Co. kinda nice to be out in shorts and flip flops in the dead of winter

2. DoubleTap says:

Yeah, when I lived down there for a bit, it was nice doing a dive outing when there was snow back home….

2. No joke says:

I see today that if some people are still given their latitude, their longitude and given their GPS coordinates they still have their head up their a\$\$. But no worries the government will save them.

3. Antique Collector says:

Shall read the article but the compasses and I have an issue.
Have yet to find a piece of material or something that I can place between my hand and the compass. Discovered some years back whatever chemistry is in my genetic makeup, I can cause a compass to stop working. 😣

4. Farmgirl says:

Very useful post, Ken. Unfortunately, I have the same compass problem AC has – cannot hold them or they go haywire. I will print this out and have the boys learn from it, however. Just have to stay close to them so I don’t get lost, I guess. :-)

1. Farmgirl says:

SoulSurvival,

haha – maybe the ‘Boot Scoot Boogie’. Think I still remember that one. Oh what a world it would be if dancing could power the world!

2. AC says:

SoulSurvival
R O W L– wrong electrical system to light up the night. Yes, actually I do like to dance, just have not had the time to do it. 🤩

5. scout says:

i have a Military Tritium Lensatic Compass and some other cheap ones. i don”t know why because in the south east you can’t get more than a mile from a log road or paved road somewhere. just pick a direction by the sun and you will come out somewhere shortly.
i have been lost and turned around hunting in the mountains on the west side before in my youth, watching tracks and not looking around at where i was going. and i’m telling you, it’s not a good feeling when the sun is starting to set, i have had to climbed to the top of those bald knobs to get my bearings more than once. a good whistle and compass would have come in handy. don’t forget the three shot thing.

6. Plainsmedic says:

A compass is great for more precise directions. Most adults now-a-days can’t tell North from South. A sad thing in my humble opinion. The sun is up there and if you engage the old brain, it’s not difficult at all. Polaris is up there too for night time. Living rural, it’s normal to know directions. If you’re uncomfortable with it, practice looking at shadows on the ground. It’s important to maintain awareness to your surroundings. If ya have even a general idea of the time of day, a shadow can show the way. With minimal practice/effort, you’ll soon be quite comfortable with directions. Nothing new here. No excuse for not knowing.

1. scout says:

in the canyon lands there is not very much sunlight at the bottoms to throw shadows for most of the day. but i’m sure you know this from experience.

1. Plainsmedic says:

Come’on scout. You know what I mean. Shadows or simply the sun itself is easily discernable. Some folks were never taught these simple things. We live in the northern hemisphere so obviously, the sun will ALWAYS be to our south. Considering the time of day, it may be east southeast all the way to west southwest. At or near noon, depending on daylight savings time, the sun WILL be directly south. Therefore, it will cast a shadow from a vertical post/pole/tree/whatever, from the vertical object towards due north.

Polaris. The big dipper. Look at the two stars furthest from the handle, that make-up the dipper portion. Starting at the bottom corner of the dipper and proceeding upwards towards and through the upper corner of the dipper. Continuing on that line, the next star ya come to is Polaris. It never moves in the sky. It is NORTH. For those who don’t know, the big dipper revolves around Polaris and this works throughout the year, whether you’re in a canyon or not.

If anyone hasn’t passed this simple thought process along to their grandchildren, please consider doing so.

7. Bob says:

Although initially dismissive of this article, I quickly realized that we live in an age where most adults under the age of 40 can’t read a roadmap, let alone find lat/long coordinates on a map, or estimate distance based on 2 lat/long positions on a map. I must remember that my own son in law was unable to read maps despite being a geologist for the BLM out west, finding his way by a handheld GPS alone, which led to some unbelievable SNAFU’s in his daily operations. None involved loss of life, fortunately, and all of which could have been avoided by simply looking at a map & interpreting it. Like one blind since birth, this deficiency was never apparent to him. He could not grasp what paper maps were all about, nor could he translate the info on a map to what he was looking at.
Apparently, this is no isolated phenomenon.

1. MamaLark says:

My daughter just told me the granddaughter who just got her license turned left when the GPS said and drove into someone’s yard. Mom – it told me to.

8. 11C/B says:

I was always taught that latitude, with 1 letter shift becomes altitude. Altitude being up and down which is your north/south. The other by default being your east/west, longitude. FWIW

9. Wendy says:

I used to teach my fourth-grade students that the LAtitudes were LAzy, lying down all the time. The LONGitudes were all LONG lines, unlike some of the latitudes, which are quite short near the poles.

10. Minerjim says:

Great primer article on Lat/Long. Degrees, minutes, seconds. Many GPS units give them in decimal degrees, say 38.9904563 North, 109.4555679 West. To covert to degrees, minutes, seconds– whole numbers are degrees, multiply the decimal portion by 60, the whole number you get then is minutes. If you take the decimal portion from this and multiply by 60 and you have seconds.
For legal land documents you will find most described by the TRS, or township/range/ section convention. But that is a topic for another time.

11. nucdoc says:

“At best, one degree of latitude and longitude would define a 70 square mile area.” should really say
“At best, one degree of latitude and longitude would define a 70 miles squared area” which would be 4900 square miles.

1. nucdoc, Thanks for pointing out my mis-speak! I’ve corrected the language above…