what does antarctica really look like? projections are important… sharon grant – idigbio...
DESCRIPTION
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!TRANSCRIPT
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/