Where is distortion especially severe

Definition projection. Term In which type of map is distortion especially severe? Definition small-scale maps. Term Acquiring data about Earth's surface from a satelite is called. Definition remote sensing. Term The first person to use the word "geography" was. Definition Eratosthenes. Term A name given to a portion of Earth's surface is a. Definition toponym. Term Situation identifies a place by its. Definition location relative to other objects.

Term Site identifies a place by its. Definition unique physical characteristics. Definition am. Term The concept that the distribution of one phenomenon is scientifically related to the location of other phenomena is. Definition spatial association. Term An area distinguished by one or more unique characteristics is a. Definition region.

Term The arrangement of a phenomenon across Earth's surface is. Definition spatial distribution. Term The division of the U.

Definition formal region. Term The frequency of something within a given unit of area is. Definition density. Term The spread of something over a given study area is. Definition concentration. Term The spatial distribution created by the U. Land Ordinance of is an example of. Definition pattern. Scale is the relationship between distance on a map or globe and distance on the earth.

Suppose you have a globe that is 40 million times smaller than the earth. Its scale is ,, Any line you measure on this globe—no matter how long or in which direction—will be one forty -millionth as long as the corresponding line on the earth.

In other words, the scale is true everywhere. This is because the globe and the earth have the same shape disregarding the complication of sphere versus spheroid. Now suppose you have a flat map that is 40 million times smaller than the earth. See the problem coming? Instead of comparing a big orange to a little orange, we're comparing a big orange to a little wafer. This map also has a scale of ,,, but because the map and the earth are differently shaped, this scale cannot be true for every line on the map.

The stated scale of a map is true for certain lines only. Which lines these are depends on the projection and even on particular settings within a projection. We'll come back to this subject in Module 4, Understanding and Controlling Distortion. Not all of the earth's curves can be represented as straight lines at the same fixed scale. Some lines must be shortened and others lengthened. Expressing map scale There are three common ways to express map scale:.

Linear scales Linear scales are lines or bars drawn on a map with real-world distances marked on them. To determine the real-world size of a map feature, you measure it on the map with a ruler or a piece of string.

Then you compare the feature's length on the string to the scale bar. A typical scale bar. Verbal scales Verbal scales are statements of equivalent distances. For example, if a 4. Representative fractions Representative fractions express scale as a fraction or ratio of map distance to ground distance.

Since the scale is a ratio, it doesn't matter what the units are. Small scale and large scale maps It's easy to mix these terms up. Here's one way to keep them straight: on a large-scale map, the earth is large so not very much of it fits on the map. On a small-scale map, the earth is small so all or most of it fits on the map.

A map of your town, or your property, is going to be a large-scale map. A continental or world map is a small-scale map.

Another way to think of the difference in terms of representative fractions. The larger the fraction, the larger the map's scale. So a , map is larger scale than a ,, map. Measuring distortion using Tissot's Indicatrix. In the nineteenth century, Nicolas Auguste Tissot developed a method to analyze map projection distortion.

An infinitely small circle on the earth's surface will be projected as an infinitely small ellipse on any given map projection. The resulting ellipse of distortion, or indicatrix , shows the amount and type of distortion at the location of the ellipse. For example, if an indicatrix is elongated from north to south, shape is correspondingly distorted at that location on the map. The same goes for east—west stretching or oblique stretching.

On a conformal map, the indicatrices are all circles, but they vary in size. On an equal area projection, the indicatrices have varying ellipticity , but the same area. The Mercator projection is conformal.

All indicatrices are circles; area distortion varies with latitude. The Sinusoidal projection preserves area. All indicatrices enclose the same area. The Equal-Area Cylindrical projection also preserves area. Shapes are distorted from north to south in middle latitudes and from east to west in extreme latitudes. In the Robinson projection, neither shape nor area is perfectly right anywhere. Both properties are nearly right in middle latitudes.