Calculating Distances with a Map
Posted on Mar 25, 2011 under Geography | 1 CommentComputers (and calculators before them) are designed to make things easier — especially things involving mathematical formulas . Instead of having to use a pencil and paper to calculate long columns of numbers, people can use an accounting calculator. To figure out how far away something is, they need only enter addresses into a computer map or GPS system.
Sure, all that automation is faster and more efficient, but what happened to the sense of accomplishment and ownership that comes from being able to do the math?
It is still possible to calculate distances on a map of california manually. You just need a ruler, and paper and pencil. (For some maps you may need a piece of string.). You can use a calculator for the math, but remember it won’t be as satisfying.
Choose two points on the map, say Sacramento and LA. Use a ruler to measure the distance between them. The string is used if the distance is curved. In that case you use the string to measure it and then measure the string with the ruler.
Next, take a look at the map’s scale. With representative ratio or fraction scales, you’ll simply multiply the measurement you took by the second or bottom number. Remember that the result will be in the same unit as the map, so if you get 63,360 inches , you’ll want to divide by 12 to get feet and then by 5280 to get miles. If the map scale is graphical, measure the graphic to determine the number of units in your original number.
This process can be repeated with any type of map, from street maps to globes to historical maps. Even astronomical maps use the same calculations, though the units of measurement are, well, astronomical.