Lesson Summary

The Earth is not flat but a three-dimensional rounded object. To represent it on a two-dimensional map, map projections are used to translate the curved surface into a flat image. Before discussing map projections, understanding coordinate systems is crucial for locating places on the Earth's surface.

• Coordinate Systems:
  • Geographical Coordinate Systems (GCS): Based on transforming the Earth's surface into an ellipsoid, using lines of latitude and longitude.
  • Projected Coordinate Systems (PCS): Represent the Earth's surface on a flat plane using x and y values on a Cartesian plane.

Map projections involve mathematical methods to transfer the Earth's curved surface onto a flat map. This process aims to preserve properties like area, shape, distance, and direction simultaneously, which is mathematically challenging. Different map projections prioritize preserving certain properties over others, leading to distortions.

• Types of Map Projections:
  • Mercator: Preserves shapes but distorts areas.
  • Lambert Conic: Preserves shape for specific areas on Earth.
  • Robinson: Attempts to compromise between distorting area, shape, and distance.

Working with GPS coordinates involves using a geographic coordinate system (GCS) like WGS84 (World Geodetic System of 1984), a standard for GPS and mapping applications. This system, based on latitude and longitude, will be used when creating maps in QGIS.