Understanding Map Projections

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CRASTER PARABOLIC Distance Scale is true along latitudes 36°46' N and S. Scale is also constant along any given latitude and is symmetrical around the equator. LIMITATIONS Useful only as a world map. USES AND APPLICATIONS Thematic world maps. The central meridian is 0°. DESCRIPTION This pseudocylindrical equal area projection is primarily used for thematic maps of the world. Also known as Putnins P4. PROJECTION METHOD Pseudocylindrical. LINEAR GRATICULES The central meridian is a straight line half as long as the equator. Parallels are unequally spaced, straight parallel lines perpendicular to the central meridian. Their spacing decreases very gradually as they move away from the equator. PROPERTIES Shape Free of distortion at the central meridian at 36°46' N and S. Distortion increases with distance from these points and is most severe at the outer meridians and high latitudes. Interrupting the projection greatly reduces this distortion. Area Equal area. Direction Local angles are correct at the intersection of 36°46' N and S with the central meridian. Direction is distorted elsewhere. 44 • Understanding Map Projections
CYLINDRICAL EQUAL A REA Direction Local angles are correct along standard parallels or standard lines. Direction is distorted elsewhere. Distance Scale is true along the equator. Scale distortion is severe near the poles. LIMITATIONS Recommended for narrow areas extending along the central line. Severe distortion of shape and scale near the poles. The central meridian is 0°, and the standard parallel is 40° N. The opposite parallel, 40° S, is also a standard parallel. DESCRIPTION Lambert first described this equal area projection in 1772. It has been used infrequently. USES AND APPLICATIONS Suitable for equatorial regions. PROJECTION METHOD A normal perspective projection onto a cylinder tangent at the equator. POINTS OF INTERSECTION The equator. LINEAR GRATICULES In the normal, or equatorial aspect, all meridians and parallels are perpendicular straight lines. Meridians are equally spaced and 0.32 times the length of the equator. Parallels are unequally spaced and farthest apart near the equator. Poles are lines of length equal to the equator. PROPERTIES Shape Shape is true along the standard parallels of the normal aspect. Distortion is severe near the poles of the normal aspect. Area There is no area distortion. Supported map projections• 45
Page 1 and 2: Understanding Map Projections GIS b
Page 3 and 4: Contents CHAPTER 1: GEOGRAPHIC COOR
Page 5: State Plane Coordinate System .....
Page 8 and 9: GEOGRAPHIC COORDINATE SYSTEMS A geo
Page 10 and 11: SPHEROIDS AND SPHERES The shape and
Page 12 and 13: DATUMS While a spheroid approximate
Page 15 and 16: 2 Projected coordinate systems Proj
Page 17 and 18: WHAT IS A MAP PROJECTION? Whether y
Page 19 and 20: PROJECTION TYPES Because maps are f
Page 21 and 22: maintained for both small-scale and
Page 23 and 24: Planar projections Planar projectio
Page 25 and 26: OTHER PROJECTIONS The projections d
Page 27: The four parameters above are used
Page 30 and 31: GEOGRAPHIC TRANSFORMATION METHODS M
Page 32 and 33: Unless explicitly stated, it’s im
Page 34 and 35: National Transformation version 2 L
Page 36 and 37: LIST OF SUPPORTED MAP PROJECTIONS A
Page 38 and 39: Loximuthal McBryde-Thomas Flat-Pola
Page 40 and 41: AITOFF USES AND APPLICATIONS Develo
Page 42 and 43: ALASKA SERIES E LIMITATIONS This pr
Page 44 and 45: AZIMUTHAL EQUIDISTANT Area Distorti
Page 46 and 47: BIPOLAR OBLIQUE CONFORMAL CONIC DES
Page 48 and 49: CASSINI-SOLDNER Area No distortion
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 100 and 101:
VAN DER GRINTEN I Distance Scale al
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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