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• http://www.icsm.gov.au/mapping/about_projections.html • http://classroom.antarctica.gov.au/exploring/mapping/map-projections • http://www.icsm.gov.au/mapping/about_projections.html• http://new.antarctica.ac.uk/apc/ • http://nsidc.org/api/metadata?id=nsidc-0075 • http://www.antarctica.ac.uk/about_antarctica/geography/maps.php • http://strangemaps.wordpress.com/?s=Antarctica • http://badarchaeology.wordpress.com/2013/01/03/old-maps-the-americas-a

nd-antarctica/

• http://www.colorado.edu/geography/gcraft/notes/mapproj/mapproj.html • http://gis.stackexchange.com/questions/664/whats-the-difference-between-

a-projection-and-a-datum

Something interesting at the end

http://www.flickr.com/photos/sbprzd/sets/72057594138628700/