Geographic scales are measures of the ratio between the actual distance between two points on the ground and their schematic representation on a plane. They are essential for when we want to make a map or plan of a territory or a house, since we cannot draw it in real size.
So if the distance between a mountain and a river is 3 kilometers (3,000 meters), we would need a huge piece of paper to draw them 3 kilometers apart. In this case, a scale is used that consists of reducing the actual size to a size suitable for the paper size proportionally.
For example, you can indicate that you will use a scale where 1 centimeter on paper is equivalent to 100,000 centimeters in reality. In such a way that the 3,000 meters of real distance between the mountain and the river that we referred to earlier, would be only 3 centimeters on paper..
This is what is called the geographic scale of the map and in the example above it would be indicated as 1: 100,000. This means that 1 centimeter on the map equals 100,000 centimeters on the actual terrain..
Therefore, 1 centimeter on paper is equal to 1,000 meters on the ground or 1 kilometer. This is because each meter is equal to 100 centimeters and in turn 1 kilometer is equal to 1,000 meters..
In the margin of the map, in addition to indicating the scale 1: 100,000, it is accompanied by a linear graphic scale. This is a bar divided into segments that reflect the scale used. For example, a three centimeter bar divided into three parts indicating from 0 to 3 kilometers.
Geographic scales have several applications:
The use of scale allows making useful maps, understanding that a map is a graphic representation of a territory. In such a way that the scale allows maintaining the proportion relationship between geographic objects (rivers, plateaus, peninsulas) at a size appropriate to the dimensions of the paper..
If a scale is not used, the maps, even if they represent the image of the terrain, would not inform us of the real proportions. So we would not have the notion of the spaces that really exist on the ground.
The main objective of a map is to allow you to explore an area, that is, to travel, be it by sea, land or air. In such a way that knowing the real distance that exists between one point and another is essential. If the map is not made to scale or does not inform what that scale is, whoever uses the map has no way of knowing that distance.
There are different types of cartographic scales depending on the size ratio, such as natural scale, reduction and enlargement. The natural is applied when a model of an object with a size equal to the natural is made.
While the enlargement is when we reproduce something at a larger size than it actually has. Whereas the reduction scale is to represent something smaller than it really is.
The scales used in Geography are called geographic scales and are used to make maps and plans. In this case, only reduction scales are used, which depending on the way of expressing them visually can be numerical scales or graphic scales.
Although less common, a scale called unit per unit can also be used. In this case, the equivalence in metric units is directly indicated, for example, 1 cm = 800 Km.
In this case 1 cm on the plane is equivalent to 800 km on the ground, being the same as the scale 1: 80,000,000, since 80,000,000 centimeters are 800 kilometers.
This refers to the quantitative relationship, that is to say, quantity expressed numerically, between the real distance and the one represented on the plane. In this way, everything that is represented on the map or plan will have proportions equivalent to the real ones but in a smaller size..
This scale is represented by two numbers separated by the vertical colon symbol (:). The first number (smaller) indicates the proportion corresponding to the measurements on paper and the second (larger) is the equivalent in reality.
In such a way that if the numerical scale 1: 100,000 appears on a map, each centimeter on the paper is equivalent to 100,000 centimeters on the ground.
Of course, depending on the size of what you want to represent on the map, a larger or smaller scale will be used. Here, the larger the number on the right, the smaller the scale is said to be.
Although it may sound like a contradiction, it is not. This is because as the number on the right is larger, the object is represented on the paper with a smaller size than the real one..
For example, if the scale is 1:10, an object or distance that actually measures 10 centimeters, on the plane it appears as 1 centimeter. That is, the difference in size between what is real and what is represented is not very large, so the object is on a large scale.
But, if the scale is 1: 1,000, then the object is being represented on the plane at a much smaller size than it actually is. Therefore, the scale at which the object is represented is said to be small.
This type of scale consists of representing the proportion of distance between reality and paper visually, that is, with a graph. It is then a matter of placing on the map a line or bar with a size defined in centimeters, but with the units corresponding to the real size (kilometers), as in a graduated ruler..
For example, a graphic scale can be a three-segment bar, alternating black and white. In this each segment can be 1 centimeter long, but indicating 1 km in each case, a total of 3 kilometers.
In such a way that any distance on the map equal to the size of that bar represents a real distance of 3 kilometers on the ground. Corresponding then to the numerical scale 1: 100,000.
Large scales are considered to be those ranging from 1: 10,000 to 1: 50,000, and are used to represent relatively small geographic areas, such as cities and towns..
These, not being too extensive, it is not necessary to reduce the scale of the representation in the diagram of the plan or map so much. Such is the case of the political map of Cuernavaca, capital of the state of Morelos in Mexico, made in scale 1: 50,000.
These are the geographic scales ranging from 1: 50,000 to 1: 500,000, suitable for medium-sized geographic areas such as a region or a small country. For example, the map of the state of Morelos in Mexico published by the Secretary of Communication and Transportation in 1999, was prepared on a scale of 1: 500,000.
These scales range from 1: 500,000 to 1: 80,000,000 or more, and are used for large areas of the planet up to the entire world. The latter refers to the so-called world maps, which can be globes or planispheres, which represent the entire earth's surface..
Both in the terrestrial globes and in the planispheres that represent the earth's surface in a plane, they are examples of the smallest scales used. For example, the decorative world map of National Geographic was performed on a scale of 1: 36,384,000.
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