Basics of map projections:
* From Spherical Earth to Flat Map, National atlas article, USGS.
* Atlas of Canada, map projections.
* Map projections, Michigan Nat. Res. -
* Hunter College, City University of New York.
* Exercise in map projections.
* Map projections.
* Map Projections, C.A. Furuti.
* Picture gallery of Map projections, TU Vienna.
* Overview of different map projections, USGS.
* University of Texas at Austin, Dept. of Geography.
* Map projections for the layman, S.A. Voser
* Map projections grouped by use, Radical cartography
* UTM projection, Centre for Topographic Information, Ottawa.
* Map projections: a working manual, J.P. Snyder, USGS, 1987.
Map projection tools:
* Application for creating custom world map projections (Flex projector, ETH Zurich).
* Tool for visualizing distortion in Map Projections, Univ. of Calif. at Santa Cruz.
* Java tool for global map projections, incl. interrupted projections, NASA GISS.
* Demonstration of different map projections, Institto de matematica, Brasil.
* Demonstration of different map projections, H. Bottomley.
* GeoCart tool for creating map projections for base maps, Mapthematics.
* Decision Support System for Map Projections of Small Scale Data, USGS.
Coordinate transformation tools:
* Online tools for coordinate conversions, APSalin
* Coordinate transformation software tools, FreeGIS.
* Coordinate transformation tool, Franson.
* Datum transformation tools, ITC.
* UTM coordinate converter, CellSpark.
* Cartographic projections library, OSGeo.
* Geographic translator, NGA
* Coordinate conversion tools, Blue Marble Geographics.
* NGS Geodetic toolkit for computing the ellipsoidal distance and more, NGS
* Coordinate conversions, SeisSoft Company.
* UTM converter and distance calculator tools, C. Taylor.
* Vertical datum transformation tool, NOAA.
* Translation libraries for raster (GDAL) and vector (OGR) data incl. coordinate transformations, GDAL.
* WGS Geoid Calculator, NGA.
* Nautical calculators, NGA.
* Coordinate conversions for New Zealand, LINZ.
* Coordinate conversion tool for world-
* Map projection equations, Wolfram MathWorld
* OGP Guidance note 7: Coord. Conversions and Trans. incl. Formulas. -
Coordinate Reference Systems in the world:
* International Terrestrial Reference Frame (ITRF).
* EPSG Geodetic Parameter Database, OGP Surveying and Positioning.
* Grids and Datums, ASPRS.
* Information and Service System for European Coordinate Reference Systems, CRSeu.
* Map projections for Europe, EUR GI & GIS.
* Collection of map projection for Europe, S.A. Voser.
* Entry page to National Mapping Agencies, ITC.
A map projection is used to portray all or part of the round Earth on a flat surface. This cannot be done without some distortion. Every projection has its own set of advantages and disadvantages. There is no "best" projection. The mapmaker must select the one best suited to the needs, reducing distortion of the most important features. Mapmakers and mathematicians have devised almost limitless ways to project the image of the globe onto paper. Scientists at the U. S. Geological Survey have designed projections for their specific needs—such as the Space Oblique Mercator, which allows mapping from satellites with little or no distortion.
This document gives the key properties, characteristics, and preferred uses of many historically important projections and of those frequently used by mapmakers today.
That site is your must to learn in simple and clear words about various Map Projections by USGS, clear illustrations and brief descriptions. You can download that material in [.pdf] format too. / or here and here
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