Cartographic Projections

Created by María Jesús Campos Fernández. Geography and History teacher. (Madrid, Spain)

1. The earth : cartographic projections María Jesús Campos Fernández

2. Terrestrial Globe The best way to represent the Earth is a globe . A terrestrial globe is a spherical model of the Earth that do not distort its surface . Not useful to study parts of the Earth in detail .

3. Cartographic projections Represent the 3-D geoid of the Earth on a flat surface or map . Every projection changes the surface of the Earth in some way . This is called distortion . Geographers use different types of projection depending on the purpose of the map they want to create and their accuracy .

4. Properties of the cartographic projections Equivalent projection : they show the proportion of landmasses accurately . Useful for comparing the surface area of territories . Equidisntant projection : they show the distance between territories accurately . Conformal projection : they show the shape of an area accurately .

5. Types of projection Cylindrical projection Conic projection Zenithal or azimuthal projection

6. Cylindrical projection They are created by putting the sphere into a cylinder and then unrolling the cylinder’s surface . Geographic coordinates are represented with straight lines . Meridians are represented in equally spaced vertical lines . Parallels are represented in equally spaced horizontal lines . Meridians and parallels have the same length . Consequences : Very little distortion in equatorial areas . Lots of distortion in the poles . Whole-world maps are rectangular.

7. Gall-Peters Projection Mercator Projection Robinson Projection

8. Conic Projection They are created by putting the sphere into a cone with an imaginary on two specific parallels and then unrolling the cone . Meridians ar e mapped to equally spaced lines radiating out from the apex of the cone . Parallels are mapped to circular arcs centered on the apex of the cone . Consequences : Very little distortion in scale , shape and area near the chosen parallels . Distance distortion increases to the north and the south of the standard parallels and decreases between the standard parallels . Lots of distortion in the poles . Whole-world maps are rectangular.

9. Lambert Projection Albers Projection

10. Zenithal projection Also called Azimuthal projections . They are created by putting a plane onto the surface of the Earth . The center of the plane is tangent to an exact place on Earth . Parallels appear as concentric lines and meridians as the radius of those circles . Consequences : Distortion increases as we get distant from the tangent point . Types : Orthographic projection Estereographic projection Gnomonic projection Lambert azimuthal projection

11. Lambert Projection

12. Developed by María Jesús Campos