trimet bus maps,
forest park maps,
whats a MILE?
The circumference of the earth is 24901.55 miles at the equator (A mile = 5280 feet)
to make this more usable we use traditional Coordinates to measure the earth (EarthMeasure=GeoGraphy)
The Symbols for traditional Coordinates are; degrees=° minutes=' and seconds="
A circle is divided by 360 degrees °(arcdegrees)
A degree is divided by 60 minutes '(arcminutes)
A minute is divided by 60 seconds "(arcseconds)
60 X 60 X 360=1296000 divisions around the earth in arcseconds
that gives a total precicion of 1/52 of a mile or 101 feet 6 inches (30.82 metres) per arcsecond
A nautical mile is defined as 1852 meters 1 arcminute of angle along a meridian on the Earth
pretty good for something invented in 150 BC
You need a referance point or measurment is worthless so your Coordinates are referanced as ;
latitude; how far north or south you are of the equater ,+90° northward and -90° southward.
longitude; how far east or west +-180° you are of greenwich england .
(In 1884, the International Meridian Conference adopted the Greenwich meridian as zero point of longitude)
last updated 3:42 PM 2/19/08
Doubts are more cruel than the worst of truths. - Molière