One of the answers to a problem posed in this text: 84 feet Go Back

BASIC GEOGRAPHY

The Earth:

7929 miles in diameter Got it?

Latitude and Longitude

LATITUDE: The numbers ranging from 60 to -60 on the left side of the picture are degrees of latitude. Latitude actually ranges from 90 to -90. (The North and South Poles, respectively) 1. Imagine a plane through the Earth at the equator. Where it intersects the surface of the earth is where zero latitude is measured. 2. Now imagine a point at the center of the earth. 3. Latitude is measured as the angle between two lines. These two lines both go through the center of the earth. One line goes through the equator. The other goes through the point at which you want to know the latitude. 4. And both lines lie in the same North/South plane.(along a line of longitude) 5. North is positive, South is Negative. 6. All lines of latitude are parallel.

LONGITUDE: The number ranging from -150 to 150 on the bottom of the picture are degrees of longitude. Longitude actually runs from -180 to 180. And -180 and 180 occur at the same place. Lines of longitude are also called meridians. Zero is located at the Greenwich Meridian. 1. Imagine a plane through the Earth. This one runs through both poles and is perpendicular to the plane through the equator. Where it intersects the surface of the earth is a line of longitude. 2. A special one runs through Greenwich England. It's where we measure zero from. 3. All lines of Longitude run through both poles. They are all the same length.

CONTINENTS:___or_Go_to__Top of the Page

There are seven continents. They are, in no particular order, listed below.

1. North America

2. South America

3. Europe

4. Asia

5. Africa

6. Antarctica

7. Australia

OCEANS:

There are five oceans. They are, in no particular order, listed below.

1. Atlantic

2. Pacific

3. Indian

4. Arctic

5. Antarctic

There are more time zones than there ought to be. One hour occupies about 15 degrees of longitude. So there ought to be 24. But there are places like Paris that are � hour off. So if you want more information, check out this link, to World Time.

Where Am I?___or_Go_to__Top of the page

As I write this, I'm in Georgia. There are actually two Georgias, but only one in the western hemisphere. My Georgia has a capital named Atlanta. The country I live in is called The United States of America. The continent you will find our country on is North America. I'm currently sitting about 30 minutes drive Northeast of the center of town (Atlanta). Now, with that information, could you find me? Probably not.

What if I told you my latitude and longitude? I could tell you I was at 3415'32.22" North, 8420'35.30" West. The ,'," are degrees minutes and seconds. North refers to a latitude, and since its North, I could have listed it as just lat: 3415'32.22". West refers to longitude, and since its West, (negative), I could have listed it as long: -8420'35.30".

How closely do those coordinates locate me?

Here's a quick calculation. Remember the earths diameter? Check the number. Got it?

Multiply that number by Pi. Yes that's right. 3.141592653589793 is close enough. Take the number you get, which is the circumference. Divide that number by 360. Now you have the no. of miles in one degree at the Equator. Divide that by 60. That's the miles in one minute of longitude at the equator. Write this number down. To find the miles at my latitude, multiply that number by the cosine of the degrees of latitude in decimal degrees. In this case that's 34.259. The cosine of 34.259 x the number you wrote down is the miles in one minute of longitude at my latitude. Divide by 60 again and multiply by 5280. Now you have the feet in one second of longitude at my latitude. Could you deliver a pizza to me yet? If your lost, Check the number and come back by pressing this button. Well? If I take it out two decimal places, you would know my location even better. In fact, the coordinates of my coffee cup, since its about 1.7 feet due east of me would be 3415'32.22" North, 8420'35.28" West. Oh yeah, I just made up those coordinates. Sure they're right there in the ball park, but I didn't have a GPS receiver handy this morning.

So what about satellite imagery? If I use two meter imagery, (about 6 ft 7 ins, my little brothers height), how many places should I take my lat/long? Email me with the answer and your reasoning. [email protected]. Then go try the Test.

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