Latitude and Longitude for Beginner Navigators

Today I received a message from my ex-student asked about latitude & longitude for his additional knowledge. He don't have any idea about that term. So I love to share what ever I can provide, so I spent my time to did some reading & writing what ever I can put in this post.

Basically, latitude and longitude are angles that uniquely define points on a sphere. Together, the angles comprise a coordinate scheme that can locate or identify geographic positions on the surfaces of planets such as the earth.

Latitude is defined with respect to an equatorial reference plane. This plane passes through the center C of the sphere, and also contains the great circle representing the equator. The latitude of a point P on the surface is defined as the angle that a straight line, passing through both P and C , subtends with respect to the equatorial plane. If P is above the reference plane, the latitude is positive (or northerly); if P is below the reference plane, the latitude is negative (or southerly). Latitude angles can range up to +90 degrees (or 90 degrees north), and down to -90 degrees (or 90 degrees south). Latitudes of +90 and -90 degrees correspond to the north and south geographic poles on the earth, respectively.

Longitude is defined in terms of meridians, which are half-circles running from pole to pole. A reference meridian, called the prime meridian , is selected, and this forms the reference by which longitudes are defined. On the earth, the prime meridian passes through Greenwich, England; for this reason it is also called the Greenwich meridian . The longitude of a point P on the surface is defined as the angle that the plane containing the meridian passing through P subtends with respect to the plane containing the prime meridian. If P is to the east of the prime meridian, the longitude is positive; if P is to the west of the prime meridian, the longitude is negative. Longitude angles can range up to +180 degrees (180 degrees east), and down to -180 degrees (180 degrees west). The +180 and -180 degree longitude meridians coincide directly opposite the prime meridian. Latitude and longitude coordinates on the earth are sometimes extended into space to form a set of celestial coordinates.

It is okay if keep asking others person if we are don't knowing well certain information in certain area. May the person willing to show you the way via many medium that are suitable best.

The right to make a copy for personal use is part of most existing publishing agreements. This right is recognised as an important right for the author. Because the right is attached to the author and in most cases well defined, personal use won’t harm the publisher.

Purifying the Water

Water is the main elements when you are in a survival mode. Human can stand for more than three days without any water intake. Beyond that timeline, surely the cells & the brain can't working at the normal condition. So that water is life!

In a fallout-contaminated area, available water sources may be contaminated. If you wait at

least 48 hours before drinking any water to allow for radioactive decay to take place and

select the safest possible water source, you will greatly reduce the danger of ingesting

harmful amounts of radioactivity.

Although many factors (wind direction, rainfall, sediment) will influence your choice in

selecting water sources, consider the following guidelines.

Water Sources

Water from springs, wells, or other underground sources that undergo natural filtration will

be your safest source. Any water found in the pipes or containers of abandoned houses or

stores will also be free from radioactive particles. This water will be safe to drink, although

you will have to take precautions against bacteria in the water.

Snow taken from 15 or more centimeters below the surface during the fallout is also a safe

source of water.

Rivers and Streams

Water from streams and rivers will be relatively free from fallout within several days after

the last nuclear explosion because of dilution. If at all possible, filter such water before

drinking to get rid of radioactive particles. The best filtration method is to dig sediment

holes or seepage basins along the side of a water source. The water will seep laterally into

the hole through the intervening soil that acts as a filtering agent and removes the

contaminated fallout particles that settled on the original body of water. This method can

remove up to 99 percent of the radioactivity in water. You must cover the hole in some way

in order to prevent further contamination. See figure below for an example of a water filter.

Still Water

Water from lakes, pools, ponds, and other standing sources is likely to be heavily

contaminated, though most of the heavier, long-lived radioactive isotopes will settle to the

bottom. Use the settling technique to purify this water. First, fill a bucket or other deep

container three-fourths full with contaminated water. Then take dirt from a depth of 10 or

more centimeters below the ground surface and stir it into the water. Use about 2.5

centimeters of dirt for every 10 centimeters of water. Stir the water until you see most dirt

particles suspended in the water. Let the mixture settle for at least 6 hours. The settling dirt

particles will carry most of the suspended fallout particles to the bottom and cover them.

You can then dip out the clear water. Purify this water using a filtration device.

Precautions

As an additional precaution against disease, treat all water with water purification tablets

from your survival kit or boil it.

The right to make a copy for personal use is part of most existing publishing agreements. This right is recognised as an important right for the author. Because the right is attached to the author and in most cases well defined, personal use won’t harm the publisher.