Geography Class 11 Notes is a crucial subject in the Social Science curriculum that requires students to have a thorough understanding of the Earth, its physical features, and human activities. The subject demands a strong foundation in conceptual knowledge and an ability to analyze and interpret geographical data. These notes provide a comprehensive summary of the key topics, aiding students in better comprehension of the subject matter.
Our Geography Notes Class 11 serves as a valuable resource to enhance your problem-solving skills and prepare for your Social Science Class 11 exams. By utilizing our comprehensive notes, you can develop a strong foundation in Geography and improve your problem-solving skills.
Need and Element of Map Projections
What is Map Projection?
Map projection is a method used to convert the curved surface of the Earth, known as the geoid, onto a flat plane surface. It involves transforming the network of latitude and longitude lines, which form a spherical grid on the Earth’s surface, onto a two-dimensional map.
The Earth is not flat but rather has a spherical shape, resembling a globe. A globe accurately represents the shape and sizes of continents and oceans, as well as directions and distances. The globe is divided into segments by lines of latitude (horizontal) and longitude (vertical), forming a grid known as a graticule.
However, globes have limitations. They are expensive, not easily portable, and cannot display detailed information. The lines of latitude and longitude, which are curved on a globe, become straight or curved intersecting lines when transferred onto a flat surface through map projection. This transformation allows for the creation of maps that are more accessible and practical for various uses.
Need For Map Projection
The reason we need map projections is to study regions in detail, which is difficult to do on a globe. Comparing different regions on a globe is also tricky. So, we draw detailed maps on flat paper to make it easier. But here’s the problem: when we try to transfer the curved lines of latitude and longitude from the globe to flat paper, they get distorted.
Imagine sticking a flat paper onto a globe – it won’t fit perfectly everywhere. When we shine light from the center of the globe onto the paper, the parts far away from where it touches the globe get distorted. This distortion gets worse the farther away you go from the point of contact. So, accurately tracing all the features like shape, size, and direction from a globe onto flat paper is almost impossible because the globe isn’t flat.
Map projection helps solve this problem. It tries to represent a part of the Earth on flat paper as accurately as possible. But there will always be some distortion. To minimize this, different methods and types of projections have been developed. So, map projection is essentially the study of different ways to transfer the lines from the globe onto flat paper.
Elements of Map Projection
|
Element |
Description |
|---|---|
|
Reduced Earth |
A scaled-down model of the Earth used for transferring the grid of latitude and longitude lines. |
|
Parallels of Latitude |
Circles parallel to the equator, running around the globe at fixed distances from the poles. |
|
Meridians of Longitude |
Semi-circles running from pole to pole, intersecting at right angles along the Earth’s axis. |
|
Global Property |
Basic properties preserved in map projection: distance between points, shape, size or area, direction. |
1. Reduced Earth: To represent the Earth on a flat sheet of paper, we use a smaller version called the “reduced earth.” This model is like a shrunken sphere, where the length from pole to pole is shorter than the length around the equator. On this model, we can transfer the grid of latitude and longitude lines.
2. Parallels of Latitude: These are circles that run parallel to the equator around the globe. They are at a fixed distance from the poles and lie in planes perpendicular to the Earth’s axis. While they’re not all the same length, they range from points at the poles to the equator. They’re labeled from 0º to 90º, both North and South.
3. Meridians of Longitude: These are semi-circles that run from one pole to the other, intersecting at right angles along the Earth’s axis. Each meridian lies in its own plane. While there’s no single central meridian, the one passing through Greenwich, England, marked as 0° longitude, is often used as a reference for all others.
4. Global Properties: When making a map projection, we aim to preserve certain fundamental properties of the Earth’s surface:
(i) Distance between any two points in a region,
(ii) Shape of the region,
(iii) Size or area of the region accurately, and
(iv) Direction from one point in the region to another.
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FAQs on Class 11 Geography Need and Elements of Map Projection
What is map projection?
Map projection is the method of transferring the graticule of latitude and longitude from a spherical surface (like the Earth) onto a flat surface (like a map).
Why do we need map projections?
We need map projections to accurately represent the Earth’s surface on a flat map, allowing for detailed study, comparison of regions, and easy visualization of geographic information.
What are the elements of map projection?
The elements include the reduced Earth (a scaled-down model), parallels of latitude (lines parallel to the equator), meridians of longitude (lines from pole to pole), and preserving global properties like distance, shape, size, and direction.
Why is it challenging to transfer lines of latitude and longitude onto a flat surface?
It’s challenging because a flat surface cannot perfectly represent the spherical Earth without distortion, leading to various methods of map projection with different types of distortion.
Why is the meridian of Greenwich often used as a reference in map projection?
The meridian of Greenwich, marked at 0° longitude, is commonly used as a reference for drawing other longitudes due to its convenience, although no meridian is inherently central.