Lesson on determining distances and heights using a globe. Scale
Compiled in accordance with the Federal State Educational Standard LLC based on the textbook by A.A. Letyagin publishing house "Ventana-Graf", the lesson includes practical tasks of working on a map and globe with explanations and solutions to more complex geographical problems
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1 option
1) Which direction corresponds to direction A - B on a fragment of the map of Russia? (underline)
a) North
b) N-E
c) NW
d) east
2) Which arrow on a fragment of the world map corresponds to the direction north?
answer________________
3)Work according to the map. Which is further north: the Cotopaxi volcano or the Aconcagua volcano? (underline)
4) Working on a map. What is the altitude in the Paris city area?_________
5) Determine the length of Australia along the meridian 130 east.
Homework. G- 6th grade. Measuring distances using a globe and map
Option 2
1) Which direction corresponds to direction A - B on a fragment of a map of Northern America? (underline)
a) north 
b) N-E
c) NW
d) east
2) Which arrow on a fragment of a map of Russia corresponds to the direction to the west?
answer________
3)Work according to the map. Which is further south: the Alps Mountains or the Atlas Mountains (underline)
4) Work on the map. What is the altitude in the Delhi city area?______________
5) Determine the length of South America along the 50W meridian.
Solution__________________________________________ Answer________
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- Get to know the concepts...
- Learn…….
- Let's determine the length of the Ural Mountains:
- Length 1 degree= 111.13 km
- 1) Let us determine the length of part of the Ural Mountains along the 60 E meridian. between Mount Magnitnaya (53.5 N) and Mount Narodnaya (65 N)
- 2) Find the difference between parallels
- 3) Find the length of the meridian arc
- Length of 1 degree meridian = 111.13 km
- The northern tip of continent Africa = 30 N latitude, and the southern tip -35 S latitude.
- Find the difference = 30 +35 = 65 degrees
- Now we find the length: 65 times 111.13 (meridian degree length) = 7223.45 km
- Determine the distance in degrees and kilometers between the two volcanoes Cameroon and Etna
- Cameroon 9 E.
- Etna 14 E.
- 14-9=5 degrees
- 5 x 111(meridian arc length)=555 km
- You can use a ruler on the map!
- Determine the extent of Africa along the Northern Tropic
- Length of 1 degree tropic = 101.7 km
- We find the meridians along which the territory of Africa begins and ends along the parallel of the tropics (23.5 north latitude)
- Then we find the extent of Africa along the Northern Tropic.
- Which Bay, the Hudson Bay or the Gulf of Mexico, has more water?
- Which sea has a larger volume of water - Kara or Okhotsk?
- Which bay is deeper - the Bay of Bengal or the Great Australian Bay?
- What is the greatest depth of the Atlantic Ocean?
- What is the height of the earth's surface in the region of Brasilia, the average height of Atlas?
- What is further south: the Himalayas or the Tien Shan?
- What's further north: the Gulf of Mexico or the Hudson?
- Which is further east: Cameroon volcano or Kilimanjaro volcano?
- What is further west: the city of Paris or Moscow?
- P.16, read to know the length of the meridian arc and parallels, isobaths, isohypses.
- learn the nomenclature on the topic “Lithosphere”
Questions before a paragraph
1. Why is the axis of the school globe inclined to the horizontal stand at an angle of 66.5 degrees?
The Earth globe is an accurate model of the planet. All geographical objects are depicted on the globe. The axis of the globe is inclined to its horizontal stand at 66.5 degrees due to the fact that the earth's axis is also inclined at the same angle. Thus, the globe not only gives an idea of what the planet looks like, but also gives an idea of its overall location in outer space.
2. How is the earth's axis oriented? What star is it pointed at?
The earth's axis is tilted relative to a straight line. The fact that the Earth's axis is not strictly vertical is of great importance for the planet. It is reliably known that our planet’s north pole is directed towards the North Star. That is why people use it to determine the northern direction at night.
3. What methods do cartographers use to depict the relief of the earth’s surface on the globe and maps?
On a globe, relief shapes are depicted as isohypses. If horizontal lines are drawn at equal distances, then isohypses are drawn in accordance with the scale: 200, 500, 1000, 1500, 2000, 3000 and then after 1000 m. The relief images are supplemented with layer-by-layer coloring. The scale of heights and depths helps characterize the relief of land and seabed on the globe. The scale is divided into levels of heights and depths. Using the height and depth scale, you can more accurately determine the height or depth in meters. Elevated areas of land are painted brown. Color saturation increases with increasing height. Unlike topographic maps, the color green on a globe is used to show plains rather than vegetation.
The underwater relief and depths of various parts of the oceans and seas are indicated on the globe by isobaths. Isopaths are lines connecting points of the bottom with the same depth. Various shades are used for layer-by-layer coloring of depths blue: the deeper, the darker.
Questions and tasks
1. Using the globe, determine which level of the altitude scale the topography of your area corresponds to.
The height scale is a scale of different color scales. The so-called high-altitude stage has its own color. As a rule, low-lying areas are green (0 - 200m). The steps above (200m and above) are painted yellow, then brown. The higher the dot, the darker the colors. It also happens the other way around. The mountains are light yellow, and the sea depressions are dark blue. Typically, the height scale is used on geographical maps, as well as hypsometric and physical maps. An elevation scale is placed in the margins of the map.
The relief of the Southern Urals is very diverse. It was formed over millions of years. Within the Chelyabinsk region there are various forms of relief - from lowlands and hilly plains to ridges whose peaks exceed 1000 m.
The West Siberian Lowland is limited from the west by a horizontal line (elevation 190 m above sea level), which passes through the villages of Bagaryak, Kunashak and further through Chelyabinsk to the south. The lowland slopes slightly to the northeast, dropping to 130 m at the eastern border of the region.
2. Using a flexible ruler, determine the distance from your locality to the largest cities in the world, for example Mexico City, New York, Tokyo, Rio de Janeiro.
Distance from Chelyabinsk to Rio de Janeiro - 13000; Mexico City - 11500; New York - 8500; Tokyo – 6100 kilometers.
3. Determine the extent of Russian territory from west to east along the Arctic Circle.
It is known that the length of one degree is 44.5 km and the Arctic Circle crosses the borders of Russia at approximately longitude 29 degrees. in the west and 171gr. in the east (180 - 29) + 9 = 160gr, 160 *44.5km=7120 km.
The shortest distance from the western border with the United States is in the Bering Strait.
The western point on the border with Finland has coordinates -67*n. w. and 32 * in. d.. Distance to the Greenwich meridian = 180 * -32 * = 148 *, and also add 11 * to 169 * W. d, to the border with America and we get the total distance in degrees = 148 + 11 = 159 *. Each degree at the 67th parallel = 52 km, which means the most short distance along the 67th parallel it will be 52 km * 161 * = 8372 km. (approximate value)
4. Determine the extent of the territory of Russia from north to south along the meridian of 45 degrees east.
To find the extent of Russia from north to south, look at the coordinates of north and south along the 45 * meridian. The northern point lies at 68*N, and in the south at 40*N. We find the difference 68*-40*=28*, 111.1*28= 3110 km
Practical work No. 1
Determining distances on the globe using a scale.
Target: To consolidate knowledge on the topic “Scale” in practice, to teach how to determine scales various cards, distinguish between types of scales, develop skills in working with maps and the globe; be able to determine distances on the globe.
Equipment: curvimeter, globe, atlas, notebook, strip of paper, ruler, pencil.
PROGRESS OF WORK
Task 1. Convert the numerical scale of the map to a named one:
a) 1: 200,000
b) 1: 10,000,000
c) 1: 25,000
Rule for students.To more easily convert a numerical scale into a named one, you need to count how many zeros the number in the denominator ends with. For example, on a scale of 1:500,000, there are five zeros in the denominator after the number 5.
If after the number in the denominator there are five more zeros, then by covering (with a finger, a pen or simply crossing out) the five zeros, we get the number of kilometers on the ground corresponding to 1 centimeter on the map. An example for a scale of 1: 500,000. In the denominator after the number there are five zeros, closing them, we get for the named scale: 1 cm on the map is 5 kilometers on the ground.
If there are less than five zeros after the number in the denominator, then by closing two zeros, we get the number of meters on the ground corresponding to 1 centimeter on the map. If, for example, in the denominator of a scale of 1: 10,000 we close two zeros, we get: 1 cm - 100 m.
Answer: a) 1 cm - 2 km; b) 1 cm - 100 km; c) 1 cm - 250 m.
Task 2. Convert the named scale to a numerical one:
a) 1 cm - 500 m
b) 1 cm - 10 km
c) 1 cm - 250 km
Rule for students.To more easily convert a named scale to a numerical one, you need to convert the distance on the ground indicated in the named scale into centimeters. If the distance on the ground is expressed in meters, in order to obtain the denominator of the numerical scale, you need to assign two zeros, if in kilometers, then five zeros.
For example, for a named scale of 1 cm - 100 m, the distance on the ground is expressed in meters, so for the numerical scale we assign two zeros and get: 1: 10,000. For a scale of 1 cm - 5 km we assign five zeros to the five and get: 1 : 500,000.
Answers: a) 1: 50,000; b) 1: 1,000,000; c) 1: 25,000,000.
Task 3. Determine the distance between points using the physical map of Russia in the 6th grade atlas:
a) Moscow and Murmansk
b) Mount Narodnaya (Ural Mountains) and Mount Belukha (Altai Mountains)
c) Cape Dezhnev (Chukchi Peninsula) and Cape Lopatka (Kamchatka Peninsula)
Rule for students.When determining the distance on a map between points, you should:
1. Using a ruler, measure the distance in centimeters between points. For example, the distance between the cities of Moscow and Astrakhan on the map is 6.5 cm.
2. Find out by the named scale how many kilometers (meters) on the ground correspond to 1 cm on the map.
(On the physical map of Russia in the 6th grade geographic atlas, 1 cm on the map corresponds to 200 km on the ground.)
3. Multiply the distance between points measured with a ruler by the number of kilometers (meters) on the ground for a given scale.
6.5 x 200 = 1300 km.
Answers: a) 1460 km; b) 2240 km; c) 2500 km.
Task 4. Measure the length of rivers using the physical map of Russia in the 6th grade atlas:
a) Oka;
b) the Ural River;
c) Kama.
Measurements of winding lines on a map (in this case, rivers) are carried out using a curvimeter or a thread.
How to measure the length of a river using a thread (rule for students).
1. The thread must be moistened, otherwise it will be difficult to lay it on the paper.
2. Attach the thread to the curved line (to the river - from source to mouth) so that it follows all the bends of the river.
3. Mark the source and mouth points on the thread (with your fingers or tweezers) (you can carefully cut the thread with scissors at these points).
4. Straighten the thread, attach the noticed (or cut) section of the thread to the ruler and measure how many centimeters it contains. The measurement result is multiplied by the number of kilometers on the ground for a given scale. (You can attach a string to the linear scale on the map and immediately read the length of the river.)
Answers: a) approximately 920 km; b) approximately 1300 km; c) approximately 1200 km.
Please note.The accuracy of measurements of curved sections is low, so the students’ answers may differ somewhat from the answers of their friends. Surely, the results of measuring with a thread on a small-scale map will VERY diverge from the river lengths indicated in textbooks and reference books. The real length of the Oka is 1500 km, the Urals - 2400 km, the Kama - 1800 km. It is imperative to tell students these numbers so that the “clumsy” numbers of independent measurement do not stick in their memory (and they have a great chance of sticking precisely because they were obtained independently). It is also necessary to explain where this discrepancy comes from: a small-scale map cannot reflect many medium and small turns, bends of the river, they are all “straightened”. This explanation will come in handy in the topic “Scale”: it will make it easier to understand the differences between maps of different scales.
For a long time there has been a special, simple device designed specifically for taking measurements on a map of both straight and winding segments called a curvimeter. Curvimeter (from Latin curvus - curve and... meter), a device for measuring the lengths of segments of curves and winding lines on topographical plans, maps and graphic documents. When using a curvimeter, you can measure the winding section of the route you need at the lowest cost and with the greatest accuracy.
Interesting
A story about a 1:1 scale map
Once upon a time there lived a Capricious King. One day he traveled around his kingdom and saw how large and beautiful his land was. He saw winding rivers, huge lakes, high mountains and wonderful cities. He became proud of his possessions and wanted the whole world to know about them. And so, the Capricious King ordered cartographers to create a map of the kingdom. The cartographers worked for a whole year and finally presented the King with a wonderful map on which all the mountain ranges were marked, major cities and large lakes and rivers.
However, the Capricious King was not satisfied. He wanted to see on the map not only the outlines of mountain ranges, but also an image of each mountain peak. Not only large cities, but also small ones and villages. He wanted to see small rivers flowing into rivers.
The cartographers set to work again, worked for many years and drew another map, twice the size of the previous one. But now the King wanted the map to show passes between mountain peaks, small lakes in the forests, streams, and peasant houses on the outskirts of villages. Cartographers drew more and more maps.
The Capricious King died before the work was completed. The heirs, one after another, ascended the throne and died in turn, and the map was drawn up and drawn up. Each king hired new cartographers to map the kingdom, but each time he was dissatisfied with the fruits of the labor, finding the map insufficiently detailed.
Finally, the cartographers drew the Incredible Map. The map depicted the entire kingdom in great detail - and was exactly the same size as the kingdom itself. Now no one could tell the difference between the map and the kingdom.
Where were the Capricious Kings going to keep their wonderful map? The casket is not enough for such a map. You will need a huge room like a hangar, and in it the map will lie in many layers. But is such a card necessary? After all, a life-size map can be successfully replaced by the terrain itself.
Dependence of map detail on scale
If you have ever flown on an airplane, then you probably remember how at the beginning of the flight, when the plane just takes off from the ground, the outlines of the airport, houses, and squares float beneath it. But the higher he rises into the air, the fewer details are visible through the porthole, but the wider the space that opens to the eye becomes wider. The detail of the maps also changes when the scale is reduced.
On large-scale maps, where no more than 500 m of earthly space fits into 1 cm of area, a small territory is depicted in great detail.
Small-scale maps, where up to several thousand kilometers fit into 1 cm, show huge areas of the Earth, but with little detail. Both cards are needed, depending on their purpose.
If you are wondering which countries you will fly over when traveling from Moscow to Melbourne, you need to open a small-scale map, and when going to the forest to pick mushrooms or go hiking with friends, you need to take a large-scale map with you so as not to get lost.
Homework for those interested
Determine the scale of maps of your area
Find maps that show the area where you live. If you don’t have such maps at home, ask your acquaintances and friends, a geography teacher, a librarian or a bookstore seller for help.
Write down the scales of maps depicting your area. Which scale is larger, which is smaller?
Compare maps of different scales and find out which scale maps show a larger area and which ones show a smaller one.
Determine which scale maps show the area in more detail, and which scales show less detail.
Draw a conclusion about how the area of the depicted territory and its detail depend on the scale of the map.
Find your location on the map
Using a map of your region (region, republic...), determine the distance from your settlement to the regional (regional, republican) center, if you do not live in it, or to some other settlement, if you are in the center of the region ( regions, republics).
We will answer the following questions.
1. What needs to be done to determine the distance between geographical objects on the globe?
2. How is the shortest distance on a globe determined?
3. In what ways are relief depicted on the globe?
We will learn to measure distances and heights (depths) on a globe, and create a three-dimensional model of the continent of Africa.
1. Determination of distances on the globe.
- Read the text of the textbook (p. 83) and write down the sequence of actions (algorithm) for determining distances along the meridian:
1) determine the coordinate values of two meridian points, the distance between which must be calculated;
2) determine the distance between two meridian points in degrees;
3) multiply the resulting distance in degrees by 111.13 km (the average length of the meridian arc is 1’).
1) 8*111.13 = 889.04 km.
- Read the text of the textbook (p. 84) and write down the sequence of actions (algorithm) for determining distances along a parallel:
2) determine the distance between two parallel points in degrees;
3) multiply the resulting distance in degrees by 111.13 km (the average arc length of a given parallel is 1 degree).
- Using the method of determining distances by parallel, determine the distance between Smolensk and Chelyabinsk (Fig. 2) from west to east along the parallel of 55 degrees north latitude.
2) 29 *111.13 = 3222.77 km
2. Image of the relief on the globe. Height and depth scale
Isohypses are horizontal lines drawn not through equal steps of heights, but in accordance with the values indicated on the horizontal and vertical scales.
On the globe, isohypses (horizontals) are drawn with a line of layer-by-layer coloring.
To depict the relief using the method of layer-by-layer coloring of the globe, the following colors are used:
Lowlands (with an absolute height of 0 to 200 m) are colored green;
Hills (with an absolute height of 200 to 500 m) are painted light brown;
Low mountains (with an absolute height of 500 to 1000 m) are painted light brown;
Medium-altitude mountains (with an absolute height of 1000 to 2000 m) are painted brown;
High mountains (with an absolute height of 2000 to 5000 m and above) are painted in richer shades of brown.
- Indicate the advantages and disadvantages of various ways of depicting the relief of the earth's surface on a globe. Fill in the blanks in the diagram.
Geographer-Pathfinder School
- Take measurements on the globe. Enter into the table the values of distances (lengths) obtained during calculations and measurements.
Compare the results obtained using different methods.
If the latitudes of two points are known, then you can find out the distance between them either in degrees or in kilometers using a globe or ruler.
- Using the drawing (color plate, p. 1), make a relief map of Africa.
The highest part of Africa is northern, the lowest is central and southern.
To measure distances using plans, maps and a globe, you must be able to use a scale that shows the degree of reduction in the length of a line on a plan, map or globe compared to the actual distance on the ground, Scales can be numerical, named and graphical (linear).
Numerical scale expressed as a fraction, where the numerator is one, and the denominator is the number m, showing how many times the distance on the map is less than the true distance on the ground, i.e. degree of reduction. For example, M=1:m=1:100000 means that on the map the length is reduced by 100000 times compared to the terrain. The numerator and denominator are given in the same measurements (centimeters). The numerical scale is usually accompanied by an explanation indicating the ratio of the lengths of the lines on the map and on the ground. In our example, 1 cm corresponds to 1 km (100,000 cm). This is the so-called named scale. It is indicated on all maps.
For direct determination of distances from maps and plans, it is used linear scale(Fig. 5). This is a graph placed at the bottom of the map in the form of a straight line divided into centimeters, and to the right of zero at each line division (for example, centimeter) the true distance on the ground is written, equal to one, two or several scale values. In our example this is 1, 2, 3 km, etc. To the left of zero, 1 cm is divided into smaller divisions, such as millimeters, to obtain more accurate results. Measure the distance on the map with a ruler or compass, transfer this distance to the scale and obtain the required distance without additional calculations. In this case, errors are inevitable, which depend on the scale and projection of the map. The larger the map scale, the more accurate the measurement result. The scale of small-scale maps of large areas is not constant in different parts of the map, so it should be taken into account that the scale indicated on them refers to certain lines or points (depending on the projection applied), and not to the entire field of the map.
Map projections
The spherical surface of the Earth, when depicted on a plane, undergoes compression or stretching, which leads to violations of the geometric properties of the objects being mapped, i.e. distortions. The mathematical method of depicting the surface of the globe (ellipsoid) on a plane is called a cartographic projection. The projection allows us to take into account inevitable distortions, especially significant on maps of the entire Earth and its large parts. On plans and large-scale maps of small areas, distortions are almost imperceptible.
There are four types of distortions on maps: lengths, areas, angles and shapes of objects.
Based on the nature of distortion, map projections are divided into equiangular, in which the angles and shape of objects are preserved, but the lengths and areas are distorted; equal in size, in which areas are preserved, but the angles and shape of objects are greatly changed; arbitrary, in which there are distortions of lengths, areas and angles, but they are distributed on the map in a certain way. Among them especially stand out equidistant projections, in which there is no distortion of lengths in certain directions.
The scale indicated on the maps is valid only on lines and at points of zero distortion. It's called the main thing. In all other parts of the map, the scale differs from the main one and is called private. To determine it, special calculations are required.
To determine the nature and magnitude of distortions on the map, it is necessary to compare the degree network of the map and the globe. On the globe, all meridians are equal to each other and intersect with parallels at right angles. Therefore, all cells of the degree network between adjacent parallels have the same size and shape, and the cells between the meridians expand and increase from the poles to the equator.
Length Distortion lies in the fact that the length scale changes on the map with a change in location and direction. The sign is that the meridian segments between adjacent parallels are phase in size.
Area distortion consists of changing the area scale on the map. Sign - unequal size and shape of cells between adjacent parallels.
Distortion of corners is that the angles on the map between certain directions do not correspond to those on the ground. The sign is a deviation from right angles between parallels and meridians on the map.
Distortion of object shapes is that the shapes of geographical objects on the map do not correspond to them in nature. Sign - the shapes of cells at the same latitude are different, but their areas are the same.
Since the maps are built on the basis of mathematical calculations, it is possible, knowing the nature of the distortions and taking them into account, to obtain fairly accurate desired results.
By construction method a distinction is made between conditional projections, which are constructed according to predetermined conditions, and projections in which the image is first transferred to an auxiliary geometric surface, and then from it to a plane. Based on the type of auxiliary surface, projections are divided into cylindrical (for world maps), conical (maps of Russia and other countries), and azimuthal (maps of hemispheres, continents, etc.).
Types of cards. Legend
Modern geographical maps are very diverse. They are divided by content, scale, purpose, and territory coverage.
In terms of content, maps can be general geographical or thematic. General geographic maps depict mainly relief, rivers, lakes, and also settlements, roads, etc. None of the objects on the map stand out particularly among the others. Thematic maps convey in greater detail one or more specific elements, depending on the theme of the map. Among them stand out physiographic maps(geological, climatic, soil, botanical, natural zoning, etc.) and socio-economic(political, political-administrative, economic, population maps, etc.).
By scale they distinguish large-scale, medium-scale and small-scale maps. Large scale (topographic) scale maps 1:200,000 and larger convey the main features of the terrain, created as a result of processing aerial photographs and through direct observations and measurements on the ground; distortions on topographic maps are very minor. Medium-scale (survey-topographic)(1:200000-1000000 inclusive) are created by large scale maps by generalization, i.e. selection and generalization of objects in accordance with the purpose of the map. Small-scale (overview) maps(smaller than 1:1000,000) are intended for studying large areas.
According to their purpose, maps are divided into educational, reference, tourist, etc.
Based on the coverage of the territory, maps of the world, hemispheres, continents and their parts, oceans and seas, states and their parts are created- republics, regions, districts, etc.
To depict geographical objects on maps, special symbols are used, explanations of which are given in map legend. The legend is the key to understanding and reading a map, so studying it must begin with the legend.
Conventional signs There are areal (contour), linear and non-scale. Area symbols include the outline of a forest, lake, city block, etc.; to linear ones - rivers, roads, canals, etc., their width is exaggerated, they can be of different colors, patterns, etc.
Special category linear signs on geographical maps make up isolines, those. lines connecting points with equal values of the depicted phenomena. To depict relief - unevenness of the earth's surface - they are used horizontal lines (isohypses)- lines on the map connecting points with the same absolute height, those. altitude above sea level. Digital values of contour lines are given at certain intervals. In addition, points are placed on the maps at watersheds and at the water edges of rivers and lakes, at which their absolute heights are indicated. The direction of the slopes is marked with short dashes - berg strokes, placed perpendicular to the horizontal and directed towards the lower slopes. The difference in heights of two adjacent horizontal lines is called height of the relief section, Knowing this value, from the number of contour lines one can calculate both the absolute and relative height of the area.
Relative height- the excess of one point in the terrain over another, for example, the top of a mountain over the foot, a floodplain over a river bed.
The depths of the sea are depicted using isobath- lines of equal depths.
Thus, horizontal lines and isobaths delimit steps with different heights and depths. On small scale physical maps the steps are emphasized by layer-by-layer coloring, and a scale of heights and depths is depicted at the bottom of the map.
Out-of-scale signs mark, for example, a well, a forester's house, a church, a monument, i.e. objects that cannot be expressed on a map scale.
On thematic maps, reflecting the various properties of natural and social phenomena, various methods of mapping are used: areas (for example, a coal basin), signs of movement (winds, sea currents), icons (settlements), etc.
Application of cards
Maps are widely used in scientific and practical activities. A map as a model of reality has great information content, visibility, and clarity. This makes her the most important means of scientific knowledge in geography and other areas of knowledge about the Earth and society. Many geographical studies start with a map and end with a map. No wonder they say: “There is no geography without a map.”
A geographical map is indispensable in solving various economic problems, related to the study and development of territories. Exploration of mineral resources, accounting and assessment of agricultural lands, waters, forests, reclamation construction, work on the design of roads, canals, power lines, industrial facilities, environmental and other activities are unthinkable without maps and plans. Maps are necessary for sailors, pilots, astronauts, meteorologists and many other specialists. The use of topographic maps in military affairs is extremely large and versatile.
The role of maps in teaching geography is enormous. And not only because it shows the placement of objects and phenomena, although this is also necessary to know. Maps allow us to establish cause-and-effect relationships and interdependencies both in nature and between natural and socio-economic objects. They develop geographical thinking.
Therefore, in school and university, a map is the most important “visual aid,” although it speaks to its reader in the language of conventional signs. It cannot be replaced either by text or by living words.
Location orientation. The concept of the horizon. Methods of orientation
Orientation on the ground includes determining one’s location relative to the sides of the horizon and noticeable terrain objects, as well as determining the direction of the path.
The horizon is the part of the earth's surface that is visible in open areas. Skyline- the boundary of visible space where it seems to us that the sky meets the earth. When the observer is raised, the range of the visible horizon increases. For a person of average height standing on level ground, it is about 5 km, when climbing 100 m - about 40 km, when rising 1000 m - about 120 km, etc.
To navigate the terrain, you need to know the sides of the horizon. Main sides of the horizon- north, east, south and west, in between- northeast, southeast, southwest, northwest. The direction of the geographic meridian running along the surface of the globe from the North to the South Pole is shown by the noon line. At noon, when the Sun is in the southern side of the sky (for residents of our country this is always true), the shadow from objects (it is the shortest) falls due north. If you stand facing north, south will be behind you, east will be on your right, and west will be on your left. At night you can navigate by the North Star, which is located almost above the north point.
It is safer and more convenient to navigate in any weather using a compass, the blue arrow of which points to the north. However, the magnetic needle of a compass is located along the magnetic, not the geographic meridian, which usually do not coincide, since the geographic and magnetic poles do not coincide. To find the exact direction north, you need to take into account the angle between ( north direction geographic meridian in the direction of the northern end of the magnetic needle, called magnetic declination. Magnetic declination is either eastern or western.
When the northern (blue) end of the magnetic compass needle deviates east of the geographic meridian the declination is called eastern and has a plus sign (positive), when deviating to the west- western and has a minus sign (negative). Magnetic declination must be indicated on all topographic maps. For example, the magnetic declination of Moscow is +8° (Fig. 4). To find out the direction of the geographic meridian, you need to count 8° to the west from the direction of the northern end of the magnetic compass needle. This will be the direction to the north.
The most reliable way to navigate the terrain is with the help of detailed map or aerial photograph, carried out by comparison cartographic image with the terrain. The position of the point at which the observer is located is determined relative to noticeable terrain objects (landmarks) by eye or by measuring distances and direction angles - azimuths. Azimuth- an angle that is measured from the northern end of the meridian clockwise to the direction towards the object (from 0 to 360°). If the angle is measured from the magnetic meridian, a magnetic azimuth is obtained, and taking into account the magnetic declination, a true (geographical) azimuth is obtained.
You can navigate in space and by local signs. Most of them are based on the smaller amount of solar heat received from north side horizon. So, for example, on the north side, trees growing in open areas have a poorer crown; stumps have less thickness of annual rings; There are more mosses and lichens on tree trunks. And anthills are usually located to the south of stumps and trees, from the south on trunks coniferous trees more resin is released, etc.
Questions and tasks:
1. What is a degree network and what is its purpose?
2. What are geographic coordinates? How are they determined by the globe and map?
3. What methods of orienteering do you know?
4. What are the main features? geographical map and site plan. What are their differences?
5. What is scale? What types of scales do you know? How can you measure distances using a map and globe?
6. What is the purpose map projections, their main types.
7. Why are distortions inevitable on maps of vast territories? Name their types.
8. What main types of cards do you know? Where are geographic maps used?