What does Antarctica really look like? Projections are important… Sharon Grant – iDigBio Train-the-Trainers Geo-referencing Workshop II. August 2013

It was easier when the world was flat! Aristotle Pythagoras Magellan

Transforming a three dimensional space onto a two dimensional map is called 'projection'. Projection formulas are mathematical expressions which convert data from a geographical location (latitude and longitude) on a sphere or spheroid to a representative location on a flat surface. Make is flat again!

Distortions All projections result in some distortion of the relationships between features on the sphere when they are projected onto a flat surface. These include: –the direction between one feature and another –the distance between one feature and another –the shape of a feature –the area of a feature These distortions are in part due to the changing relationship between latitude and longitude as you move around the earth. Near the Equator a ‘block’ of 1°x1° latitude and longitude is almost a square, however the same ‘block’ near the poles is almost a triangle.

China’s 1418 World Map / Piri Re’s 1513 / / Oronce Fine heart-shaped map 1531

Mercator

Lambert conformal conic

Azimuthal equidistant

Polar stereographic

Resources and-antarctica/ and-antarctica/ a-projection-and-a-datumhttp://gis.stackexchange.com/questions/664/whats-the-difference-between- a-projection-and-a-datum

Something interesting at the end / /