The United Kingdom and United States had been using Greenwich as the Prime Meridian for several decades before the conference.
Why was computing longitude so difficult?
It wasn’t until the sixteenth century that clocks were fabricated in such a way that they could accurately tell time both on land and at sea. The only way of determining how far east or west one could go is by plotting the stars in two locations and recording the exact time in both locations simultaneously, and then recording the time and position at the destination. As clocks became more accurate, the ability to measure speed and distance became possible.
How can I remember which way latitude and longitude run?
You can remember that the lines of latitude run east and west by thinking of lines of latitude as rungs on a ladder (“ladder-tude”). Lines of longitude are quite “long” because they run from the North Pole to the South Pole.
How can a gazetteer help me find latitude and longitude?
A gazetteer is an index that lists the latitude and longitude of places within a specific region or across the entire world. Many atlases include a gazetteer, and some are published separately.
How can I find the latitude and longitude of a particular place?
To find latitude and longitude of a particular location, you will need to consult either a gazetteer, database, or website that includes longitude and latitude data. Though gazetteers are readily accessible, they don’t include as many places as online databases. There are a number of sites on the Internet that have extensive databases of latitude and longitude and even include such specific places as public buildings.
What is the difference between a physical map and a political map?
A physical map shows natural features of the land such as mountains, rivers, lakes, streams, and deserts. A political map shows human-made features and boundaries such as cities, highways, and countries. The maps we use in atlases and see on the walls of classrooms are typically a combination of the two.
What is a topographic map?
A topographic map shows human and physical features of the Earth and can be distinguished from other maps by its great detail and by its contour lines indicating elevation. Topographic maps are excellent sources of detailed information about a very small area of the Earth. The United States Geological Survey (USGS) produces a set of topographic maps for the United States that are at a scale of 1:24,000 (one inch equaling 2,000 feet [or 1 centimeter equaling about 240 km]). You can purchase these maps online, at sporting goods stores, or through the USGS itself.
Why are road maps so difficult to fold?
The problem lies with the multitude of folds required to return the map to its original, folded shape. The easiest way to fold a road map is to study the creases and to fold the map in the order that the creases will allow. But once you’ve made a mistake, the folds have lost their telltale instructions. To fold a road map, begin by folding it accordion style, making sure that the “front” and “back” of the folded design appear on top. Then, once the entire map is folded accordion style, fold the remaining slim, long, folded paper into three sections. And, voilà, your road map is folded!
Why is color important on a relief map?
A relief map portrays various elevations in different colors. But, a common color scheme found on relief maps causes a problem. On these maps, mountains are displayed as red or brown, while lowlands are shown in shades of green. This is confusing because the green areas on the map are often misconstrued as fertile land, while brown areas are mistaken for deserts. For example, an area such as California’s Death Valley, which is shown in green on relief maps because it lies below sea level, seems fertile, when actually it is an inhospitable desert.
What does the scale of a map tell me?
A scale indicates the level of detail and defines the distances between objects on a map. On a map, scales can be written as a fraction, a verbal description, or as a bar scale. A fraction, or ratio, using the example of 1/100,000 or 1:100,000, indicates that one unit of any form of measurement on the map is equivalent to 100,000 units of the same measurement in the area being represented. For instance, if you use inches as the unit of measurement, then one inch on the map would equal 100,000 inches in the area represented by the map.
A map scale will show you how a distance on a map translates to mileage in the real world.
A verbal description describes the relationship as if it were a verbal instruction, such as “one inch equals one mile.” This allows the versatility of having different units of measurement.
What is a bar scale?
A bar scale uses a graphic to show the relationship between distance on the map to distance in the area represented. The bar scale is the only type of scale that allows a reduction or enlargement of the map without distorting the scale. This is because when you increase the size of the map, the bar scale is increased proportionally. For a fraction or verbal scale, the proportion (1:1,000) is only true for the map at that size. For example, when enlarging a map, the map might become twice as large, but the numbers in a ratio do not change as they would need to in order to stay accurate.
How can I determine the distance between two places by using a scale?
By using a ruler, compare the distance between two points on a map with the information on the scale to calculate the actual distances between the two points. For example, if you measure the distance between two towns as being five inches and the ratio says 1:100,000, then the actual distance between the towns is 500,000 inches or 7.9 miles (12.7 km).
What is the difference between small- and large-scale maps?
A small-scale map shows a small amount of detail over a wide area, such as the world. A large-scale map shows a large amount of detail while representing a limited area, such as neighborhoods or towns.
Why is every map distorted?
No map is completely accurate because it is impossible to accurately represent the curved surface of the Earth on a flat piece of paper. A map of a small area usually has less distortion because there is only a slight curve of the Earth to contend with. A map of a large area, such as maps of continents or the world, are significantly distorted because the curvature of the Earth over such a large area is extreme. This means that many places around the world may appear smaller or larger than they actually are, depending on where on the map the place is located.
How is the Earth’s surface like an orange peel?
Any attempt to represent a sphere, like the Earth, in a flat representation results in distortions. The surface of the Earth is like the peel of an orange. When we try to take the “peel” of the surface of the Earth and lay that onto a flat piece of paper like a map, large, open areas are created. Mapmakers correct for these distortions, so there are as few distortions as possible. The strategies for correcting for these problems are referred to as “projections.”
In many types of projection maps, Greenland appears much larger than it actually is because of distortion caused by keeping the lines of latitude and longitude straight.
Why does Greenland appear larger on most maps than it actually is?
Because of the distortions that must appear on all maps, many maps place the distortion in the northern and southern extremes of the Earth. In one of the common projections, known as Mercator, Greenland appears to be similar in size to South America, despite the fact that South America is actually eight times larger than Greenland. The advantage of the Mercator projection is that the lines of latitude and longitude remain perpendicular; thus, the map is useful for navigation.