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 NAME     
 |  |  |  | map, mapdemo, mapd – draw maps on various projections 
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 SYNOPSIS     
 |  |  |  | map projection [ option ... ] 
    
    
    mapdemo | 
 DESCRIPTION     
 |  |  |  | Map prepares on the standard output a map suitable for display
    by any plotting filter described in plot(1). A menu of projections
    is produced in response to an unknown projection. Mapdemo is a
    short course in mapping. 
    
    
    The default data for map are world shorelines. Option −f accesses
    more detailed data classified by feature. −f [ feature ... ]
 
 In other options coordinates are in degrees, with north latitude
    and west longitude counted as positive.|  |  |  | Features are ranked 1 (default) to 4 from major to minor. Higher-numbered
        ranks include all lower-numbered ones. Features are shore[1-4]     seacoasts, lakes, and islands; option −f always shows
        shore1
 ilake[1-2]     intermittent lakes
 river[1-4]     rivers
 iriver[1-3]    intermittent rivers
 canal[1-3]     3=irrigation canals
 glacier
 iceshelf[12]
 reef
 saltpan[12]
 country[1-3]   2=disputed boundaries, 3=indefinite boundaries
 state        states and provinces (US and Canada only)
 
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 −l S N E W
 
 −k S N E W|  |  |  | Set the southern and northern latitude and the eastern and western
        longitude limits. Missing arguments are filled out from the list
        –90, 90, –180, 180, or lesser limits suitable to the projection
        at hand. 
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 −o lat lon rot|  |  |  | Set the scale as if for a map with limits −l S N E W . Do not
        consider any −l or −w option in setting scale. 
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 −w S N E W|  |  |  | Orient the map in a nonstandard position. Imagine a transparent
        gridded sphere around the globe. Turn the overlay about the North
        Pole so that the Prime Meridian (longitude 0) of the overlay coincides
        with meridian lon on the globe. Then tilt the North Pole of the
        overlay along its Prime Meridian to latitude lat on the globe.
        Finally again turn
        the overlay about its ‘North Pole’ so that its Prime Meridian
        coincides with the previous position of meridian rot. Project
        the map in the standard form appropriate to the overlay, but presenting
        information from the underlying globe. Missing arguments are filled
        out from the list 90, 0, 0. In the absence of −o, the orientation
        is 90, 0, m, where m is
        the middle of the longitude range. 
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 −d n   For speed, plot only every nth point.|  |  |  | Window the map by the specified latitudes and longitudes in the
        tilted, rotated coordinate system. Missing arguments are filled
        out from the list –90, 90, –180, 180. (It is wise to give an encompassing
        −l option with −w. Otherwise for small windows computing time
        varies inversely with area!) 
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 −r    Reverse left and right (good for star charts and inside-out
    views).
 −v    Verso. Switch to a normally suppressed sheet of the map, such
    as the back side of the earth in orthographic projection.
 −s1
 −s2   Superpose; outputs for a −s1 map (no closing) and a −s2 map
    (no opening) may be concatenated.
 −g dlat dlon res
 
 −p lat lon extent|  |  |  | Grid spacings are dlat, dlon. Zero spacing means no grid. Missing
        dlat is taken to be zero. Missing dlon is taken the same as dlat.
        Grid lines are drawn to a resolution of res (2° or less by default).
        In the absence of −g, grid spacing is 10°. 
 | 
 
 −c x y rot|  |  |  | Position the point lat, lon at the center of the plotting area.
        Scale the map so that the height (and width) of the nominal plotting
        area is extent times the size of one degree of latitude at the
        center. By default maps are scaled and positioned to fit within
        the plotting area. An extent overrides option −k. 
 | 
 
 −m [ file ... ]|  |  |  | After all other positioning and scaling operations have been performed,
        rotate the image rot degrees counterclockwise about the center
        and move the center to position x, y, where the nominal plotting
        area is –1≤x≤1, –1≤y≤1. Missing arguments are taken to be 0. −x Allow
        the map to extend outside the nominal plotting area. | 
 
 −b [lat0 lon0 lat1 lon1... ]|  |  |  | Use map data from named files. If no files are named, omit map
        data. Names that do not exist as pathnames are looked up in a
        standard directory, which contains, in addition to the data for
        −f, world     World Data Bank I (default)
 states    US map from Census Bureau
 counties   US map from Census Bureau
 The environment variables MAP and MAPDIR change the default map
        and default directory.
 
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 −t file ...|  |  |  | Suppress the drawing of the normal boundary (defined by options
        −l and −w). Coordinates, if present, define the vertices of a
        polygon to which the map is clipped. If only two vertices are
        given, they are taken to be the diagonal of a rectangle. To draw
        the polygon, give its vertices as a −u track. 
 | 
 
 −u file ...|  |  |  | The files contain lists of points, given as latitude-longitude
        pairs in degrees. If the first file is named −, the standard input
        is taken instead. The points of each list are plotted as connected
        ‘tracks’. Points in a track file may be followed by label strings. A label
        breaks the track. A label may be prefixed by ", :, or ! and is
        terminated by a newline. An unprefixed string or a string prefixed
        with " is displayed at the designated point. The first word of
        a : or ! string names a special symbol (see option −y). An optional
        numerical second word is
        a scale factor for the size of the symbol, 1 by default. A : symbol
        is aligned with its top to the north; a ! symbol is aligned vertically
        on the page.
 
 | 
 
 −y fileThe file contains plot(7)-style data for : or ! labels
    in −t or −u files. Each symbol is defined by a comment :name then
    a sequence of m and v commands. Coordinates (0,0) fall on the
    plotting point. Default scaling is as if the nominal plotting
    range were ra −1 −1 1 1; ra commands in file change the scaling.|  |  |  | Same as −t, except the tracks are unbroken lines. (−t tracks appear
        as dot-dashed lines if the plotting filter supports them.) 
 | 
 Projections     mercator          equally spaced straight meridians, conformal, straight
    compass coursesEquatorial projections centered on the Prime Meridian (longitude
    0). Parallels are straight horizontal lines.
 sinusoidal         equally spaced parallels, equal-area, same as bonne
    0.
 cylequalarea lat0     equally spaced straight meridians, equal-area,
    true scale on lat0
 cylindrical        central projection on tangent cylinder
 rectangular lat0     equally spaced parallels, equally spaced straight
    meridians, true scale on lat0
 gall lat0           parallels spaced stereographically on prime meridian,
    equally spaced straight meridians, true scale on lat0
 mollweide         (homalographic) equal-area, hemisphere is a circle
 
 gilbert           globe mapped conformally on hemisphere, viewed orthographically
    
    
    
    Azimuthal projections centered on the North Pole. Parallels are
    concentric circles. Meridians are equally spaced radial lines.
    
    
    
    azequidistant      equally spaced parallels, true distances from pole|  |  |  | |  |  |  | gilbert() sphere conformally mapped on hemisphere and viewed orthographically 
 | 
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 azequalarea        equal-area
 gnomonic          central projection on tangent plane, straight great circles
 perspective dist     viewed along earth’s axis dist earth radii from
    center of earth
 orthographic       viewed from infinity
 stereographic      conformal, projected from opposite pole
 laueradius = tan(2×colatitude), used in X-ray crystallography
 fisheye n          stereographic seen from just inside medium with refractive
    index n
 newyorker rradius = log(colatitude/r): New Yorker map from viewing
    pedestal of radius r degrees 
    
    
    Polar conic projections symmetric about the Prime Meridian. Parallels
    are segments of concentric circles. Except in the Bonne projection,
    meridians are equally spaced radial lines orthogonal to the parallels.
    
    
    
    conic lat0          central projection on cone tangent at lat0
 simpleconic lat0 lat1   equally spaced parallels, true scale on lat0
    and lat1
 lambert lat0 lat1      conformal, true scale on lat0 and lat1
 albers lat0 lat1       equal-area, true scale on lat0 and lat1
 bonne lat0          equally spaced parallels, equal-area, parallel lat0
    developed from tangent cone 
    
    
    Projections with bilateral symmetry about the Prime Meridian and
    the equator. 
    
    
    polyconic         parallels developed from tangent cones, equally spaced
    along Prime Meridian
 aitoff            equal-area projection of globe onto 2-to-1 ellipse, based
    on azequalarea
 lagrange          conformal, maps whole sphere into a circle
 bicentric lon0       points plotted at true azimuth from two centers
    on the equator at longitudes ±lon0, great circles are straight
    lines (a stretched gnomonic )
 elliptic lon0       points plotted at true distance from two centers
    on the equator at longitudes ±lon0
 globular          hemisphere is circle, circular arc meridians equally spaced
    on equator, circular arc parallels equally spaced on 0- and 90-degree
    meridians
 vandergrinten      sphere is circle, meridians as in globular, circular
    arc parallels resemble mercator 
    
    
    Doubly periodic conformal projections. 
    
    
    guyou            W and E hemispheres are square
 square            world is square with Poles at diagonally opposite corners
 tetra            map on tetrahedron with edge tangent to Prime Meridian at
    S Pole, unfolded into equilateral triangle
 hex              world is hexagon centered on N Pole, N and S hemispheres are
    equilateral triangles 
    
    
    Miscellaneous projections. 
    
    
    harrison dist angle    oblique perspective from above the North Pole,
    dist earth radii from center of earth, looking along the Date
    Line angle degrees off vertical
 trapezoidal lat0 lat1   equally spaced parallels, straight meridians
    equally spaced along parallels, true scale at lat0 and lat1 on
    Prime Meridian
 
 Retroazimuthal projections. At every point the angle between vertical
    and a straight line to ‘Mecca’, latitude lat0 on the prime meridian,
    is the true bearing of Mecca. 
    
    
    mecca lat0          equally spaced vertical meridians|  |  |  | |  |  |  | lune(lat,angle) conformal, polar cap above latitude lat maps to
            convex lune with given angle at 90°E and 90°W | 
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 homing lat0         distances to Mecca are true 
    
    
    Maps based on the spheroid. Of geodetic quality, these projections
    do not make sense for tilted orientations. For descriptions, see
    corresponding maps above. 
    
    
    sp_mercator
 sp_albers lat0 lat1
 
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 EXAMPLES     
 |  |  |  | map perspective 1.025 −o 40.75 74 
 map mercator −o 49.25 −106 180|  |  |  | A view looking down on New York from 100 miles (0.025 of the 4000-mile
        earth radius) up. The job can be done faster by limiting the map
        so as not to ‘plot’ the invisible part of the world: map perspective
        1.025 −o 40.75 74 −l 20 60 30 100. A circular border can be forced
        by adding option −w 77.33. (Latitude 77.33° falls just
        inside a polar cap of opening angle arccos(1/1.025) = 12.6804°.) 
 | 
 
 map albers 28 45 −l 20 50 60 130 −m states|  |  |  | An ‘equatorial’ map of the earth centered on New York. The pole
        of the map is placed 90° away (40.75+49.25=90) on the other side
        of the earth. A 180° twist around the pole of the map arranges
        that the ‘Prime Meridian’ of the map runs from the pole of the
        map over the North Pole to New York instead of down the back side
        of the earth. The
        same effect can be had from map mercator −o 130.75 74 
 | 
 
 map harrison 2 30 −l −90 90 120 240 −o 90 0 0|  |  |  | A customary curved-latitude map of the United States. 
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 |  |  |  | A fan view covering 60° on either side of the Date Line, as seen
        from one earth radius above the North Pole gazing at the earth’s
        limb, which is 30° off vertical. The −o option overrides the default
        −o 90 0 180, which would rotate the scene to behind the observer. 
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 FILES     
 |  |  |  | /lib/map/[1−4]??   World Data Bank II, for −f /lib/map/*       maps for −m
 /lib/map/*.x      map indexes
 mapd            Map driver program
 
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 SOURCE     
 SEE ALSO     
 DIAGNOSTICS     
 |  |  |  | ‘Map seems to be empty’--a coarse survey found zero extent within
    the −l and −w bounds; for maps of limited extent the grid resolution,
    res, or the limits may have to be refined. 
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 BUGS     
 |  |  |  | Windows (option −w) cannot cross the Date Line. No borders appear
    along edges arising from visibility limits. Segments that cross
    a border are dropped, not clipped. Excessively large scale or
    −d setting may cause long line segments to be dropped. Map tries
    to draw grid lines dotted and −t tracks dot-dashed. As very few
    plotting filters properly
    support curved textured lines, these lines are likely to appear
    solid. The west-longitude-positive convention betrays Yankee chauvinism.
    Gilbert should be a map from sphere to sphere, independent of
    the mapping from sphere to plane. 
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