A geographical map is a fairly capacious and easily perceived product that contains a huge amount of useful information. To make all this information conveniently “readable”, cartographers have come up with a huge arsenal of special symbols. And in this article we will talk about one of them.
What is isotherm in geography and cartography? What does it look like and what information does it carry?
What is an isotherm (in geography): definition and essence of the concept
On geographical maps it is possible to show not only really existing objects (for example, mountains or seas), but also various phenomena, as well as processes (for example, the amount of precipitation in a particular territory). To do this, isolines are used (from the Greek word ισος - "equal"). In cartography, there are several dozen different contours. One of them is the isotherm.
What is an isotherm? In geography, these are conditional lines connecting points on the map with the same air temperature. With their help, scientists evaluate and compare the climatic features of various regions of the planet. Thus, isotherms are widely used in meteorology, climatology, and also in geography.
What is an isotherm from a philological point of view? This term consists of two ancient Greek words: "isos" - "equal, the same" and "terma" - "heat". As a rule, two types of isotherms are distinguished:
- summer (they are indicated in red);
- winter (they are indicated in blue).
How isothermal conduct?
So, what is the isotherm in geography, we figured out. Now let's find out how they are applied to a geographical map.
Everything is extremely simple here. First, information is collected from ground-based meteorological observation points. Then, the locations of these points and the values of the given parameter at each specific point are applied to the cartographic base (in our case, this is air temperature). Next, points with the same values are connected by smooth curved lines - isotherms.
In the gaps of these lines (as well as at their ends), the corresponding temperature values are signed. To make the map more visible, the gaps between isotherms very often fill with colors, changing their tone and saturation.
Isotherms are a very convenient mapping tool. They are simple, intuitive and require little explanation in the map legend. They work well with many other cartographic signs and are ideal for creating computer maps.