Projecting global datasets to achieve equal areas

Cartography and Geographic Information Science
By: , and 



Scientists routinely accomplish global modeling in the raster domain, but recent research has indicated that the transformation of large areas through map projection equations leads to errors. This research attempts to gauge the extent of map projection and resampling effects on the tabulation of categorical areas by comparing the results of three datasets for seven common projections. The datasets, Global Land Cover, Holdridge Life Zones, and Global Vegetation, were compiled at resolutions of 30 arc-second, 1/2 degree, and 1 degree, respectively. These datasets were projected globally from spherical coordinates to plane representations. Results indicate significant problems in the implementation of global projection transformations in commercial software, as well as differences in areal accuracy across projections. The level of raster resolution directly affects the accuracy of areal tabulations, with higher resolution yielding higher accuracy. If the raster resolution is high enough for individual pixels to approximate points, the areal error tends to zero. The 30-arc-second cells appear to approximate this condition.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Projecting global datasets to achieve equal areas
Series title Cartography and Geographic Information Science
DOI 10.1559/152304003100010956
Volume 30
Issue 1
Year Published 2003
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Cartography and Geographic Information Science
First page 69
Last page 79
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