For a long time, people were interested in what is located beyond the horizon - new territories or the edge of the earth. Centuries passed, civilization accumulated knowledge. The time has come when scientists who have never been to distant lands knew a lot about them. In this they were helped by sources of geographical information.
This article will tell you about what it is, as well as about their varieties.
General concepts
As you might guess, this is the name of all sources of information from which a person can get information of interest to him. What are the sources of geographic information considered in Grade 5 (at a secondary school)? Let's list them:
- All geographical maps, atlases, as well as a variety of topographic plans, including the military.
- A variety of geographical descriptions of a particular area.
- Directories, encyclopedic articles, results and reports of various expeditions.
- Aerial photographs and satellite imagery.
- GIS and GPS / GLONASS systems .
Here are the sources of geographic information for Grade 5 in an average comprehensive school. We will try to consider the characteristics of some of them in a little more detail.
Modern technologies
In recent years, more and more sources are being converted from paper to digital. And this is not surprising. Almost all 5 sources of geographic information that we just talked about today can be found in digital form. In recent years, even professional scientists have chosen to work with the “digit”.
Using the same GIS system is much more convenient than working with a pile of books. Now let's discuss some sources of geographic information in more detail.
Cards
A card is a schematic generalized image of the surface of a piece of land, an entire planet or celestial bodies. It is built on the principle of scaling, that is, mathematical methods are used for this. It is depending on the scale that all cards are usually divided into three large groups:
- Large scale.
- Medium-sized.
- Small scale.
If we talk about the first category, then these documents have a ratio of 1: 200,000 and larger. This includes almost all topographic plans. Small maps are all maps with a ratio of less than 1: 1,000,000. A regular geographic atlas includes either small-scale or medium-sized plans that are best suited for exploring a particular area.
Sort map information
You should know that long before the creation of the map, specialists make a strict selection of what will be displayed on it. This process is called as follows: cartographic generalization. Naturally, the most stringent selection exists with respect to small-scale maps, since they need to accommodate the maximum amount of useful information with a minimum footprint of the document. In the generalization itself, the immediate purpose of the card, as well as the wishes of its customer, play an extremely important role.
Terrain Plans
These are the so-called drawings of the area, which are carried out on a large scale (1: 5000 or more), and are drawn using special symbols. In this they resemble a school geographic atlas. The construction of such plans is carried out on the basis of eye, instrumental measurements, aerial photography or the combined method.
Since the plans indicate relatively small areas of the earth's surface, when they are created, the curvature of the planet can be neglected. It should be clearly understood that these sources of geographic information that we just described are fundamentally different from each other.
The main differences between plans and maps
- In the centimeter of the plan, rarely more than five real kilometers are laid on the ground. They are much more detailed maps, in which one millimeter can be laid hundreds of kilometers of the earth's surface.
- All objects on the ground in the plans are depicted as detailed as possible. In principle, on the average drawing marked all more or less significant areas. So, on the topographic plans of the General Staff of the RF Armed Forces (and the USSR, of course) even trees and small streams can be displayed. It is impossible to fit all this information onto cards. Actually, that's why generalization is being carried out, about which we spoke above. Even the exact outline of the continents cannot be displayed on many maps, and therefore they are often applied with significant distortions. In addition, the above additional geographic literature uses off-scale conventions.
- We emphasize once again that when constructing the plan, the curvature of the earth's surface is neglected. Maps, especially on a small scale, take it into account without fail.
- The plans never have a degree grid. At the same time, parallels and meridians are on each of them.
- The plan is always simple in terms of orientation. The top of the document is north, the bottom, respectively, is south. On maps, the direction is determined by parallels.
Methods of depicting objects on plans and maps
Conventional signs in this case are generally accepted options in which the characteristic of the objects depicted on the map or plan is encoded. With their help, you can display something specific (a mountain, for example), and something completely abstract, conditional (population density in a city, village, etc.). Of course, all of them significantly facilitate the life of a person who knows the basics of cartography and knows how to read these drawings.
How long does the card remain relevant?
Almost all geographers and geologists ask this question at least once. The specific answer to it depends on the purpose, scope, author of the plan. So, medieval scholars often drew maps literally “on their knees”, so we no longer have to talk about their accuracy. But the cards of the General Staff, despite the time, still amaze with their accuracy.
Do not forget that the maps of the Far North are quite stable, while the plans of the Amazon and the Nile can be safely thrown away fifty years after their publication. These rivers so effectively and quickly change the relief of the Earth’s surface, that from older documents there is sense only in a historical perspective.
Geographical descriptions, discoveries
All sources of geographic information discussed above are somehow dry, uninteresting. It is much more interesting to read the description of a region, locality or even the mainland, written by the person who discovered all this!
Joking as a joke, but descriptions and reports on geographical (geodesic, biological) studies can sometimes provide much more information than the most detailed topographic plan of the area. Moreover, the latter does not reflect some unpleasant features of a particular area (malaria, which occurs in some central regions of Africa at every step, for example).
The list of literature on geography that students receive at school (for example, Nikolina V.V. Geography, Workmanship; Samkova V.A. We study the forest; Forest Encyclopedia: in 2 volumes / Ch. Ed. G. I. Vorobyov ), which was formed due to the work of researchers, who at one time brought all this information to the map, being in the thick of things.
Brief information on the discovery of Africa
Let's tell a little about the history of the discovery of the Black Continent. Of course, the word "discovery" is not entirely correct here: here is Australia - yes, I had to suffer with it. In the case of Africa, coastal areas were perfectly explored, where black slaves were caught and ivory bought from Arab merchants, but practically no one knew what was going on in the depths of the continent.
Everything changed in the 19th century, when the legendary David Livingston arrived in Africa . It belongs to him the honor of discovering the origins of the Nile and the magnificent Lake Victoria. Few people know, but the Russian scientist V.V. Juncker (in 1876-1886) was engaged in the research of Central Africa at one time.
For the native population of the mainland, all this ended sadly: the main sources of geographic information (that is, maps), the data for which all these brave scientists collected with such difficulty and constant danger to life, began to be actively used by slave traders ...
So, with the maps and plans we are actually done. Geographic atlases belong to the same category. And what is the role of modern sources of geographic information? To answer this question, we consider the principle of sharing old paper maps and a navigator, which even professional geographers and geologists are actively using now.
GPS / GLONASS + maps
It should be noted that this method is excellent for determining the accuracy of maps, atlases and topographic plans. In addition, this technique satisfies the needs of historians, as they can see for themselves how much the terrain has changed, which is described in historical chronicles by contemporaries of certain events. However, the literature on geography often contains plans for the area, which have not been updated since the beginning of the last century.
To use such an accurate, but rather time-consuming and somewhat extravagant method, you will have to do three-time binding (three different maps) to the same area:
- First, find a more or less modern map or topographic plan.
- It is advisable to have a fresh aerospace image of the investigated area with topographic reference to the coordinate system.
- Finally, you need that card, the information of which you are going to check.
The meaning of this operation is to memorize the navigator all three of these terrain drawings. Modern models of such devices have a fairly powerful processor and an impressive amount of RAM, so that you can switch between cards instantly.
Route determination
Routing is best done using a modern map or topographic plan. We do not recommend using old documents for this. It is possible that in the place of the swamp there is now a passable area, but you will not be able to go through the edge of the once rare young forest, since the geography has radically changed in the area. A map is good, but in most cases such documents are not very accurate.
Why is aerial photography and satellite images preferable to maps?
But why are paper drawings so inferior to modern technology products? There are two reasons for this:
- First, the relevance of satellite imagery or aerial photography in most cases is much higher. When else will cartographers be able to conduct the next generalization of new data and release relevant plans for the area?
- In the pictures you can literally in real time be able to determine the characteristics of a particular area. On a map or even a topographic plan, tree species in the forest will be displayed only schematically and only in general order. Simply put, stumbling into a thick spruce forest in the middle of a birch forest is quite realistic, and in a dense coniferous forest it is much easier to get lost.
Choosing a route and checking with new pictures, it is recommended to refer to the old map. Why such difficulties? Imagine that you are a field biologist. You need to determine how much the forest has grown, what new species of trees have appeared, how many types of forests have changed over all these years. Ideal for solving all these problems is a simple overlay of a new card on its old counterpart. Thus, everything becomes visible as clearly as possible.
These are the sources geography uses. The map is perhaps the most important of them, but do not forget that over the past decades, science and technology have taken a huge step forward, and therefore it is stupid not to use all modern achievements.
Conclusion
So you found out which sources of geographic information are currently the most relevant. Oddly enough, but we still apply all the same plans and maps that were invented before our era. Of course, adjusted for their modern look.