Understanding Map Projections

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VAN DER GRINTEN I Distance Scale along the equator is correct. LIMITATIONS Can represent the world, but the most accurate representation is between the 75th parallels of latitude. USES AND APPLICATIONS Used for world maps. Formerly the standard world map projection of the National Geographic Society. The central meridian is 56° E. DESCRIPTION This projection is similar to the Mercator projection except that it portrays the world with a curved graticule. The overall effect is that area is distorted less than on a Mercator projection, and the shape is distorted less than on equal area projections. PROJECTION METHOD The Van der Grinten I projection is a compromise projection and is not in one of the more traditional classifications. LINEAR GRATICULES The equator and the central meridian of the projection. PROPERTIES Shape Distortion increases from the equator to the poles. Area Minimal distortion along the equator and extreme distortion in the polar regions. Direction Local angles are correct only at the center. 94 • Understanding Map Projections
VERTICAL NEAR-SIDE PERSPECTIVE Equatorial aspect—The equator. Polar aspect—All meridians. PROPERTIES Shape Minimal distortion near the center; maximal distortion near the edge. Area Minimal distortion near the center; maximal distortion near the edge. Direction True direction from the central point. The central meridian is 0°, and the latitude of origin is 90° S. DESCRIPTION Unlike the Orthographic projection, this perspective projection views the globe from a finite distance. This perspective gives the overall effect of the view from a satellite. PROJECTION METHOD Planar perspective projection, viewed from a specified distance above the surface. All aspects are either circular or an area less than a full hemisphere. Distance The radial scale decreases with distance from the center. LIMITATIONS Limited to a view less than 90 degrees from the central point. USES AND APPLICATIONS Uses of this projection are aesthetic more than technical. The most commonly used aspect for this purpose is the oblique. Polar aspect—Meridians are straight lines radiating from the center, and the lines of latitude are projected as concentric circles that become closer toward the edge of the globe. Equatorial aspect—The central meridian and the equator are straight lines. The other meridians and parallels are elliptical arcs. POINT OF CONTACT A single point located anywhere on the globe. LINEAR GRATICULES All aspects—The central meridian of the projection. Supported map projections• 95
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Understanding Map Projections GIS b
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Contents CHAPTER 1: GEOGRAPHIC COOR
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State Plane Coordinate System .....
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GEOGRAPHIC COORDINATE SYSTEMS A geo
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SPHEROIDS AND SPHERES The shape and
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DATUMS While a spheroid approximate
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2 Projected coordinate systems Proj
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WHAT IS A MAP PROJECTION? Whether y
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PROJECTION TYPES Because maps are f
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maintained for both small-scale and
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Planar projections Planar projectio
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OTHER PROJECTIONS The projections d
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The four parameters above are used
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GEOGRAPHIC TRANSFORMATION METHODS M
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Unless explicitly stated, it’s im
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National Transformation version 2 L
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LIST OF SUPPORTED MAP PROJECTIONS A
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Loximuthal McBryde-Thomas Flat-Pola
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AITOFF USES AND APPLICATIONS Develo
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ALASKA SERIES E LIMITATIONS This pr
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AZIMUTHAL EQUIDISTANT Area Distorti
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BIPOLAR OBLIQUE CONFORMAL CONIC DES
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CASSINI-SOLDNER Area No distortion
Page 50 and 51: CRASTER PARABOLIC Distance Scale is
Page 52 and 53: DOUBLE STEREOGRAPHIC Oblique aspect
Page 54 and 55: ECKERT II The central meridian is 1
Page 56 and 57: ECKERT IV parallels. Nearer the pol
Page 58 and 59: ECKERT VI central meridian. Scale i
Page 60 and 61: EQUIDISTANT CYLINDRICAL LINES OF CO
Page 62 and 63: GALL’S STEREOGRAPHIC Area Area is
Page 64 and 65: GEOCENTRIC COORDINATE SYSTEM Geogra
Page 66 and 67: GNOMONIC PROPERTIES Shape Increasin
Page 68 and 69: HAMMER-AITOFF LIMITATIONS Useful on
Page 70 and 71: KROVAK Direction Local angles are a
Page 72 and 73: LAMBERT CONFORMAL CONIC Area Minima
Page 74 and 75: LOXIMUTHAL Distance Scale is true a
Page 76 and 77: MERCATOR Greenland is only one-eigh
Page 78 and 79: MOLLWEIDE Distance Scale is true al
Page 80 and 81: ORTHOGRAPHIC PROPERTIES Shape Minim
Page 82 and 83: PLATE CARRÉE Direction North, sout
Page 84 and 85: POLYCONIC Direction Local angles ar
Page 86 and 87: RECTIFIED SKEWED ORTHOMORPHIC DESCR
Page 88 and 89: SIMPLE CONIC Equirectangular projec
Page 90 and 91: SPACE OBLIQUE MERCATOR DESCRIPTION
Page 92 and 93: Montana—The three zones for Monta
Page 94 and 95: TIMES LIMITATIONS Useful only for w
Page 96 and 97: 10,000,000 meters to ensure that al
Page 98 and 99: UNIVERSAL POLAR STEREOGRAPHIC Area
Page 102 and 103: WINKEL I Distance Generally, scale
Page 104 and 105: WINKEL T RIPEL Distance Generally,
Page 107 and 108: Glossary angular units The unit of
Page 109 and 110: High Accuracy Reference Network A r
Page 111: UTM See Universal Transverse Mercat
Page 114 and 115: Eckert VI 52 ED 1950 6 Ellipse 101
Page 116: Projections (continued) planar 17,
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Understanding Map Projections

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