This texture uses ETOPO1 data from "http://www.ngdc.noaa.gov/mgg/global/global.html:
 http://www.ngdc.noaa.gov/mgg/global/relief/ETOPO1/data/bedrock/grid_registered/georeferenced_tiff/
 in the alpha channel, and parts of world.topo.bathy.200407.3x4996x2048.png in the rgb channels.
 See 00README.txt in the same folder for information about the image usage policy of world.topo.bathy.200407.3x4996x2048.png

 How to Cite ETOPO1:
 Amante, C. and B. W. Eakins, ETOPO1 1 Arc-Minute Global Relief Model: Procedures, Data Sources and Analysis.
 NOAA Technical Memorandum NESDIS NGDC-24, 19 pp, March 2009.

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