Table of contents
world - world map generation program from <PLOT79> package
world[1,4,b,r,s,v,z]
where the final character indicates the desired output device
(4 for the Tektronix 4014 in the default Sun installation)
(see plot79 manual page for complete list)
World
draws maps of the world, using a variety of coordinate systems. It sends
prompts to the standard output requesting information to define the style
of map. The map coordinates must appear in file mapfile. A message
is sent to standard output, a run-time
listing is sent to listfile, and an optional sitefile may
specify points on the map which are to be marked (it contains a list
of [longitude,latitude,name] triples in format [2f9.3,1x,a]).
The plottable output is sent to a file named by the CRT environment variable,
or to CRT.num if CRT is undefined
(num is a number which begins at 1 and is
incremented appropriately to prevent files being overwritten).
The program may be employed for any spherical system.
Longitude and latitude values are measured in floating-point degrees.
The arguments requested by the program are:
-
BLON
-
Beginning longitude for projection.
-
ELON
-
Ending longitude for projection. This may
be smaller than BLON, in which case the
projection is assumed to cross the
180-degree meridian, and the internval value
of ELON will automatically be increased by
360 degrees.
-
BLAT
-
Beginning latitude for projection. For
polar projections, only the sign is
relevant; a negative value selects a south
polar view, and a zero or positive value a
north polar view.
-
ELAT
-
Ending latitude for projection.
-
CLON
-
Longitude of center of projection.
-
CLAT
-
Latitude of center of projection.
-
ELEV
-
Relative elevation of viewer above the
Earth's surface, expressed as a fraction of
the planetary radius. Earth has a mean
radius of 6378.0 km, so that a viewer
elevation of 250 km would be expressed as
ELEV = 250.0/6378.0 = 0.039197.
Not all of these parameters are required by each
projection. Here is a list of those actually used:
Proj. Description Parameters Required
1 Rectangular BLAT, BLON, ELAT, ELON
2 Mercator BLAT, BLON, ELAT, ELON
3 Polar Equidistant BLAT
4 Orthographic Equatorial CLAT, CLON
5 Orthographic Polar BLAT
6 Azimuthal Equidistant CLAT, CLON
7 Perspective BLAT, BLON, ELEV, ELAT, ELON
8 Cylindrical Equal Area BLAT, BLON, ELAT, ELON
The usual cartographic convention is adopted that latitude
runs from -90 degrees at the South Pole through 0 at the
Equator to +90 degrees at the North Pole, and that
longitude runs from 0 degrees through Greenwich, England,
eastward to 180 degrees in the Pacific Ocean and back to
Greenwich at 360 degrees. Longitude is thus synonomous
with East Longitude; West Longitude can be considered a
negative value which when incremented by 360 degrees
becomes East Longitude.
The map projection routines will internally automatically
adjust longitudes in the interval [-360 to 720] to the interval
[0 to 360]; latitude values are assumed to be confined to the
interval [-90 to +90]. Unpredicatable results may occur if
this convention is not adhered to.
-
/usr/local/plot79/map/world.map
-
Hershey World Data Bank I world outline map
-
/usr/local/plot79/map/usa.map
-
Hershey World Data Bank I USA outline map
-
usr/local/plot79/map/*.sf3
-
source files for world*
-
/usr/local/plot79/world*
-
executable file (world4 on the default Sun installation)
-
/usr/local/plot79/define
-
various environment definitions, an appropriate subset of which should be
placed in the user's .cshrc or .profile file
document (1L), drawit(1L), grapht(1L), graph3t(1L), lptops(1L), pfort(1L),
piechtt(1L), plot79-intro(1L), plot79(1L), pluto(1L), pretty(1L), rdinfo(1L),
sf3(1L), slides(1L), tekalw(1L), tkvecs(1L), tmacro(1L)
A. V. Hershey, "Terrestrial and Celestial
Cartography", Report NSWC/DL TR-3789, May 1979,
Naval Surface Weapons Center, Dahlgren, VA 22448.
William D. Johnson, "Computer Generated Maps. Part I", pp.
10-12, 76-101, Byte Magazine, Vol. 4, No. 5 (May 1979), and
"Computer Generated Maps. Part II", pp. 100-123, ibid, No.
6 (June 1979).
J. E. Jackson, "Sphere, Spheroid and Projections for
Surveyors", Granada Publishing Ltd. (1980).
Nelson H. F. Beebe, Ph.D.
Center for Scientific Computing
South Physics Building
University of Utah
Salt Lake City, UT 84112
Tel: (801) 581-5254
(Manual page by R. P. C. Rodgers, Computer Applications in Laboratory
Medicine Project, UCSF, San Francisco, CA 94143).