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
ilake[1–2] intermittent lakes
iriver[1–3] intermittent rivers
canal[1–3] 3=irrigation canals
country[1–3] 2=disputed boundaries, 3=indefinite boundaries
state states and provinces (US and Canada only)
–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
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.|
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.|
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!)
–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.
–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
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.
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
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.
Same as –t, except the tracks are unbroken lines. (–t tracks appear
as dot–dashed lines if the plotting filter supports them.)|
The file contains plot(6)–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
Equatorial projections centered on the Prime Meridian (longitude
0). Parallels are straight horizontal lines.
mercator equally spaced straight meridians, conformal, straight
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
gilbert() sphere conformally mapped on hemisphere and 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
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
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
lambert lat0 lat1 conformal, true scale on lat0 and lat1
equally spaced parallels, 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
polyconic parallels developed from tangent cones, equally spaced
along Prime Meridian
aitoff equal–area projection of globe onto 2–to–1 ellipse, based on
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
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
harrison dist angleoblique 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
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.
equally spaced parallels, straight meridians equally spaced along
parallels, true scale at lat0 and lat1 on Prime Meridian|
lune(lat,angle) conformal, polar cap above latitude lat maps to
convex lune with given angle at 90°E and 90°W
mecca lat0 equally spaced vertical meridians
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_albers lat0 lat1