Map Projections | Class 11 Geography Notes

MAP PROJECTION

Map projection is the systematic method of transferring the graticule—that is, the network of latitude and longitude lines—from the spherical surface of the Earth onto a flat plane surface. The Earth is geoid in shape, resembling a sphere, and a globe is the most accurate model to represent it. On a globe, the shapes, sizes, directions, and distances of continents and oceans are shown accurately. The globe is divided by horizontal lines called parallels of latitude and vertical lines called meridians of longitude. This network of parallels and meridians is called the graticule, which facilitates the drawing of maps. However, drawing the graticule on a flat surface is called projection. Since the Earth is spherical, transferring this network onto a flat surface inevitably causes distortions. The meridians are semi-circles and parallels are circles on the globe, but when projected on a flat surface, they become straight or curved intersecting lines. Globes, though accurate, have limitations such as being expensive, not easily portable, and unable to show minor details. Therefore, map projections are essential for practical and detailed geographic studies.

📊 Diagram: Figure 4.1 Conversions from a Globe to a flat surface produces distortions in area, shape and directions.

🔗 Connection: Leads to the discussion on the need for map projection, explaining why globes are insufficient and why projections are necessary.