Wikipedia:Graphics Lab/Resources/QGIS/Get ready: Difference between revisions

Revision as of 14:36, 4 September 2011

Revision as of 14:38, 4 September 2011

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[[file:QGis_ETOPO1_vs_SRTM3_-_quality_match.jpeg|thumb|600px|Quality comparison between ETOPO1 (pixelated) and SRTM3 (smoother) data sets. This difference doesn't matter for making large maps with coverage greater than 1000km (~620mi) across.]]

* {{Cite GIS |name=ETOPO1 |url_download=http://www.ngdc.noaa.gov/mgg/global/global.html |publisher=[[NGDC]]-[[NOAA]] |year=2009 |license= Public ___domain |tag= |url_doc=http://www.ngdc.noaa.gov/mgg/global/etopo1sources.html |layers=topography & bathymetry |precision_max=1850m (1minute arch) |covered_area= all Earth (90N-90S, landmass & sea floor) |datum=WSG 84 |projection = (?) |extensions=.zip → .tif and others |size_compressed=326Mo |size_uncompressed=900Mo |tile_size=whole earth |tiles_total= 1 |comment = Perfect for very large maps (ex: > France). Download: [http://www.ngdc.noaa.gov/mgg/global/relief/ETOPO1/data/ice_surface/grid_registered/georeferenced_tiff/ ETOPO1 Ice Surface (grid registered)], [http://www.ngdc.noaa.gov/mgg/global/relief/ETOPO1/data/bedrock/grid_registered/georeferenced_tiff/ ETOPO1 Bedrock (grid-registered)]. nb: ETOPO1 is a better data than ETOPO2 (lower quality). |editor_note= }}

* (not working) [http://www.ngdc.noaa.gov/mgg/topo/gltiles.html GLOBE] (topography)

**16 files/tiles to cover the all the Earth (landmass)

**medium quality; unzipped landmass file is ~1.8GB

* {{Cite GIS |name= SRTM3 v2 |url_download= http://dds.cr.usgs.gov/srtm/version2_1/SRTM3 |publisher= NASA |year= 2000 |license= Public Domain |url_doc= http://dds.cr.usgs.gov/srtm/version2_1/Documentation/SRTM_Topo.pdf |layers= topography |precision_max= 93m (3"arch) |covered_area= 60⁰N-56⁰S (landmass only) |datum= WGS 84 |extensions= .zip → .hgt |size_compressed= ~2Mo each |size_uncompressed= ~4Mo each |tile_size= 1⁰ x 1⁰arch |tiles_total= ~20.000 |comment = perfect for small areas anywhere in the world. }}