tmap.1 - plan9port - [fork] Plan 9 from user space
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tmap.1 (13546B)
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1 .TH MAP 1
2 .SH NAME
3 map, mapdemo, mapd \- draw maps on various projections
4 .SH SYNOPSIS
5 .B map
6 .I projection
7 [
8 .I option ...
9 ]
10 .PP
11 .B mapdemo
12 .PP
13 .SH DESCRIPTION
14 .I Map
15 prepares on the standard output a
16 map suitable for display by any
17 plotting filter described in
18 .IR plot (1).
19 A menu of projections is produced in response to an unknown
20 .IR projection .
21 .I Mapdemo
22 is a short course in mapping.
23 .PP
24 The default data for
25 .I map
26 are world shorelines.
27 Option
28 .B -f
29 accesses more detailed data
30 classified by feature.
31 .TP
32 .BR -f " [ \fIfeature\fR ... ]"
33 Features are ranked 1 (default) to 4 from major to minor.
34 Higher-numbered ranks include all lower-numbered ones.
35 Features are
36 .RS
37 .TF country[1-3]
38 .TP
39 .BR shore [ 1 - 4 ]
40 seacoasts, lakes, and islands; option
41 .B -f
42 always shows
43 .B shore1
44 .TP
45 .BR ilake [ 1 - 2 ]
46 intermittent lakes
47 .TP
48 .BR river [ 1 - 4 ]
49 rivers
50 .TP
51 .BR iriver [ 1 - 3 ]
52 intermittent rivers
53 .TP
54 .BR canal [ 1 - 3 ]
55 .BR 3 =irrigation
56 canals
57 .TP
58 .BR glacier
59 .TP
60 .BR iceshelf [ 12 ]
61 .TP
62 .BR reef
63 .TP
64 .BR saltpan [ 12 ]
65 .TP
66 .BR country [ 1 - 3 ]
67 .BR 2 =disputed
68 boundaries,
69 .BR 3 =indefinite
70 boundaries
71 .TP
72 .BR state
73 states and provinces (US and Canada only)
74 .PD
75 .RE
76 .PP
77 In other options
78 coordinates are in degrees, with north latitude
79 and west longitude counted as positive.
80 .TP 0
81 .BI -l " S N E W"
82 Set the southern and northern latitude
83 and the eastern and western longitude limits.
84 Missing arguments are filled out from the list
85 \-90, 90, \-180, 180,
86 or lesser limits suitable to the
87 projection at hand.
88 .TP
89 .BI -k " S N E W
90 Set the scale as if for a map with limits
91 .B -l
92 .I "S N E W"\f1.
93 Do not consider any
94 .B -l
95 or
96 .B -w
97 option in setting scale.
98 .TP
99 .BI -o " lat lon rot"
100 Orient the map in a nonstandard position.
101 Imagine a transparent gridded sphere around the globe.
102 Turn the overlay about the North Pole
103 so that the Prime Meridian (longitude 0)
104 of the overlay coincides with meridian
105 .I lon
106 on the globe.
107 Then tilt the North Pole of the
108 overlay along its Prime Meridian to latitude
109 .I lat
110 on the globe.
111 Finally again turn the
112 overlay about its `North Pole' so
113 that its Prime Meridian coincides with the previous position
114 of meridian
115 .IR rot .
116 Project the map in
117 the standard form appropriate to the overlay, but presenting
118 information from the underlying globe.
119 Missing arguments are filled out from the list
120 90, 0, 0.
121 In the absence of
122 .BR - o ,
123 the orientation is 90, 0,
124 .IR m ,
125 where
126 .I m
127 is the middle of the longitude range.
128 .TP
129 .BI -w " S N E W"
130 Window the map by the specified latitudes
131 and longitudes in the tilted, rotated coordinate system.
132 Missing arguments are filled out from the list \-90, 90, \-180, 180.
133 (It is wise to give an encompassing
134 .B -l
135 option with
136 .BR -w .
137 Otherwise for small windows computing time
138 varies inversely with area!)
139 .TP
140 .BI -d " n"
141 For speed, plot only every
142 .IR n th
143 point.
144 .TP
145 .B -r
146 Reverse left and right
147 (good for star charts and inside-out views).
148 .ns
149 .TP
150 .B -v
151 Verso.
152 Switch to a normally suppressed sheet of the map, such as the
153 back side of the earth in orthographic projection.
154 .TP
155 .B -s1
156 .br
157 .ns
158 .TP
159 .B -s2
160 Superpose; outputs for a
161 .B -s1
162 map (no closing) and a
163 .B -s2
164 map (no opening) may be concatenated.
165 .TP
166 .BI -g " dlat dlon res"
167 Grid spacings are
168 .IR dlat ,
169 .IR dlon .
170 Zero spacing means no grid.
171 Missing
172 .I dlat
173 is taken to be zero.
174 Missing
175 .I dlon
176 is taken the same as
177 .IR dlat .
178 Grid lines are drawn to a resolution of
179 .I res
180 (2° or less by default).
181 In the absence of
182 .BR - g ,
183 grid spacing is 10°.
184 .TP
185 .BI -p " lat lon extent"
186 Position the point
187 .I lat, lon
188 at the center of the plotting area.
189 Scale the map so that the height (and width) of the
190 nominal plotting area is
191 .I extent
192 times the size of one degree of latitude
193 at the center.
194 By default maps are scaled and positioned
195 to fit within the plotting area.
196 An
197 .I extent
198 overrides option
199 .BR -k .
200 .TP
201 .BI -c " x y rot"
202 After all other positioning and scaling operations
203 have been performed, rotate the image
204 .I rot
205 degrees counterclockwise about the center
206 and move the center to position
207 .IR x ,
208 .IR y ,
209 where the nominal plotting area is
210 .RI \-1≤ x ≤1,
211 .RI \-1≤ y ≤1.
212 Missing arguments are taken to be 0.
213 .BR -x
214 Allow the map to extend outside the nominal plotting area.
215 .TP
216 .BR -m " [ \fIfile\fP ... ]"
217 Use
218 map data from named files.
219 If no files are named, omit map data.
220 Names that do not exist as pathnames are looked up in
221 a standard directory, which contains, in addition to the
222 data for
223 .BR -f ,
224 .RS
225 .LP
226 .TF counties
227 .TP
228 .B world
229 World Data Bank I (default)
230 .TP
231 .B states
232 US map from Census Bureau
233 .TP
234 .B counties
235 US map from Census Bureau
236 .PD
237 .RE
238 .IP
239 The environment variables
240 .B MAP
241 and
242 .B MAPDIR
243 change the default
244 map and default directory.
245 .TP
246 .BI -b " \fR[\fPlat0 lon0 lat1 lon1\fR... ]"
247 Suppress the drawing of the normal boundary
248 (defined by options
249 .BR -l
250 and
251 .BR -w ).
252 Coordinates, if present, define the vertices of a
253 polygon to which the map is clipped.
254 If only two vertices are given, they are taken to be the
255 diagonal of a rectangle.
256 To draw the polygon, give its vertices as a
257 .B -u
258 track.
259 .TP
260 .BI -t " file ..."
261 The
262 .I files
263 contain lists of points,
264 given as latitude-longitude pairs in degrees.
265 If the first file is named
266 .LR - ,
267 the standard input is taken instead.
268 The points of each list are plotted as connected `tracks'.
269 .IP
270 Points in a track file may be followed by label strings.
271 A label breaks the track.
272 A label may be prefixed by
273 \fL"\fR,
274 .LR : ,
275 or
276 .L !
277 and is terminated by a newline.
278 An unprefixed string or a string prefixed with
279 .L
280 "
281 is displayed at the designated point.
282 The first word of a
283 .L :
284 or
285 .L !
286 string names a special symbol (see option
287 .BR -y ).
288 An optional numerical second word is a scale factor
289 for the size of the symbol, 1 by default.
290 A
291 .L :
292 symbol is aligned with its top to the north; a
293 .L !
294 symbol is aligned vertically on the page.
295 .TP
296 .BI -u " file ..."
297 Same as
298 .BR -t ,
299 except the tracks are
300 unbroken lines.
301 .RB ( -t
302 tracks appear as dot-dashed lines if the plotting filter supports them.)
303 .TP
304 .BI -y " file
305 The
306 .I file
307 contains
308 .MR plot (7) -style
309 data for
310 .L :
311 or
312 .L !
313 labels in
314 .B -t
315 or
316 .B -u
317 files.
318 Each symbol is defined by a comment
319 .BI : name
320 then a sequence of
321 .L m
322 and
323 .L v
324 commands.
325 Coordinates (0,0) fall on the plotting point.
326 Default scaling is as if the nominal plotting range were
327 .LR "ra -1 -1 1 1" ;
328 .L ra
329 commands in
330 .I file
331 change the scaling.
332 .SS Projections
333 Equatorial projections centered on the Prime Meridian
334 (longitude 0).
335 Parallels are straight horizontal lines.
336 .PP
337 .PD 0
338 .TP 1.5i
339 .B mercator
340 equally spaced straight meridians, conformal,
341 straight compass courses
342 .TP
343 .B sinusoidal
344 equally spaced parallels,
345 equal-area, same as
346 .LR "bonne 0" .
347 .TP
348 .BI cylequalarea " lat0"
349 equally spaced straight meridians, equal-area,
350 true scale on
351 .I lat0
352 .TP
353 .B cylindrical
354 central projection on tangent cylinder
355 .TP
356 .BI rectangular " lat0"
357 equally spaced parallels, equally spaced straight meridians, true scale on
358 .I lat0
359 .TP
360 .BI gall " lat0"
361 parallels spaced stereographically on prime meridian, equally spaced straight
362 meridians, true scale on
363 .I lat0
364 .TP
365 .B mollweide
366 (homalographic) equal-area, hemisphere is a circle
367 .br
368 .B gilbert()
369 sphere conformally mapped on hemisphere and viewed orthographically
370 .TP
371 .B gilbert
372 globe mapped conformally on hemisphere, viewed orthographically
373 .PD
374 .PP
375 Azimuthal projections centered on the North Pole.
376 Parallels are concentric circles.
377 Meridians are equally spaced radial lines.
378 .PP
379 .PD 0
380 .TP 1.5i
381 .B azequidistant
382 equally spaced parallels,
383 true distances from pole
384 .TP
385 .B azequalarea
386 equal-area
387 .TP
388 .B gnomonic
389 central projection on tangent plane,
390 straight great circles
391 .TP
392 .BI perspective " dist"
393 viewed along earth's axis
394 .I dist
395 earth radii from center of earth
396 .TP
397 .B orthographic
398 viewed from infinity
399 .TP
400 .B stereographic
401 conformal, projected from opposite pole
402 .TP
403 .B laue
404 .IR radius " = tan(2\(mu" colatitude ),
405 used in X-ray crystallography
406 .TP
407 .BI fisheye " n"
408 stereographic seen from just inside medium with refractive index
409 .I n
410 .TP
411 .BI newyorker " r"
412 .IR radius " = log(" colatitude / r ):
413 .I New Yorker
414 map from viewing pedestal of radius
415 .I r
416 degrees
417 .PD
418 .PP
419 Polar conic projections symmetric about the Prime Meridian.
420 Parallels are segments of concentric circles.
421 Except in the Bonne projection,
422 meridians are equally spaced radial
423 lines orthogonal to the parallels.
424 .PP
425 .PD 0
426 .TP 1.5i
427 .BI conic " lat0"
428 central projection on cone tangent at
429 .I lat0
430 .TP
431 .BI simpleconic " lat0 lat1"
432 equally spaced parallels, true scale on
433 .I lat0
434 and
435 .I lat1
436 .TP
437 .BI lambert " lat0 lat1"
438 conformal, true scale on
439 .I lat0
440 and
441 .I lat1
442 .TP
443 .BI albers " lat0 lat1"
444 equal-area, true scale on
445 .I lat0
446 and
447 .I lat1
448 .TP
449 .BI bonne " lat0"
450 equally spaced parallels, equal-area,
451 parallel
452 .I lat0
453 developed from tangent cone
454 .PD
455 .PP
456 Projections with bilateral symmetry about
457 the Prime Meridian
458 and the equator.
459 .PP
460 .PD 0
461 .TP 1.5i
462 .B polyconic
463 parallels developed from tangent cones,
464 equally spaced along Prime Meridian
465 .TP
466 .B aitoff
467 equal-area projection of globe onto 2-to-1
468 ellipse, based on
469 .I azequalarea
470 .TP
471 .B lagrange
472 conformal, maps whole sphere into a circle
473 .TP
474 .BI bicentric " lon0"
475 points plotted at true azimuth from two
476 centers on the equator at longitudes
477 .IR ±lon0 ,
478 great circles are straight lines
479 (a stretched
480 .IR gnomonic
481 )
482 .TP
483 .BI elliptic " lon0"
484 points plotted at true distance from
485 two centers on the equator at longitudes
486 .I ±lon0
487 .TP
488 .B globular
489 hemisphere is circle,
490 circular arc meridians equally spaced on equator,
491 circular arc parallels equally spaced on 0- and 90-degree meridians
492 .TP
493 .B vandergrinten
494 sphere is circle,
495 meridians as in
496 .IR globular ,
497 circular arc parallels resemble
498 .I mercator
499 .PD
500 .PP
501 Doubly periodic conformal projections.
502 .PP
503 .TP 1.5i
504 .B guyou
505 W and E hemispheres are square
506 .PD 0
507 .TP
508 .B square
509 world is square with Poles
510 at diagonally opposite corners
511 .TP
512 .B tetra
513 map on tetrahedron with edge
514 tangent to Prime Meridian at S Pole,
515 unfolded into equilateral triangle
516 .TP
517 .B hex
518 world is hexagon centered
519 on N Pole, N and S hemispheres are equilateral
520 triangles
521 .PD
522 .PP
523 Miscellaneous projections.
524 .PP
525 .PD 0
526 .TP 1.5i
527 .BI harrison " dist angle"
528 oblique perspective from above the North Pole,
529 .I dist
530 earth radii from center of earth, looking
531 along the Date Line
532 .I angle
533 degrees off vertical
534 .TP
535 .BI trapezoidal " lat0 lat1"
536 equally spaced parallels,
537 straight meridians equally spaced along parallels,
538 true scale at
539 .I lat0
540 and
541 .I lat1
542 on Prime Meridian
543 .PD
544 .br
545 .B lune(lat,angle)
546 conformal, polar cap above latitude
547 .I lat
548 maps to convex lune with given
549 .I angle
550 at 90\(deE and 90\(deW
551 .PP
552 Retroazimuthal projections.
553 At every point the angle between vertical and a straight line to
554 `Mecca', latitude
555 .I lat0
556 on the prime meridian,
557 is the true bearing of Mecca.
558 .PP
559 .PD 0
560 .TP 1.5i
561 .BI mecca " lat0"
562 equally spaced vertical meridians
563 .TP
564 .BI homing " lat0"
565 distances to Mecca are true
566 .PD
567 .PP
568 Maps based on the spheroid.
569 Of geodetic quality, these projections do not make sense
570 for tilted orientations.
571 For descriptions, see corresponding maps above.
572 .PP
573 .PD 0
574 .TP 1.5i
575 .B sp_mercator
576 .TP
577 .BI sp_albers " lat0 lat1"
578 .SH EXAMPLES
579 .TP
580 .L
581 map perspective 1.025 -o 40.75 74
582 A view looking down on New York from 100 miles
583 (0.025 of the 4000-mile earth radius) up.
584 The job can be done faster by limiting the map so as not to `plot'
585 the invisible part of the world:
586 .LR "map perspective 1.025 -o 40.75 74 -l 20 60 30 100".
587 A circular border can be forced by adding option
588 .LR "-w 77.33" .
589 (Latitude 77.33° falls just inside a polar cap of
590 opening angle arccos(1/1.025) = 12.6804°.)
591 .TP
592 .L
593 map mercator -o 49.25 -106 180
594 An `equatorial' map of the earth
595 centered on New York.
596 The pole of the map is placed 90\(de away (40.75+49.25=90)
597 on the
598 other side of the earth.
599 A 180° twist around the pole of the map arranges that the
600 `Prime Meridian' of the map runs from the pole of the
601 map over the North Pole to New York
602 instead of down the back side of the earth.
603 The same effect can be had from
604 .L
605 map mercator -o 130.75 74
606 .TP
607 .L
608 map albers 28 45 -l 20 50 60 130 -m states
609 A customary curved-latitude map of the United States.
610 .TP
611 .L
612 map harrison 2 30 -l -90 90 120 240 -o 90 0 0
613 A fan view covering 60° on either
614 side of the Date Line, as seen from one earth radius
615 above the North Pole gazing at the
616 earth's limb, which is 30° off vertical.
617 The
618 .B -o
619 option overrides the default
620 .BR "-o 90 0 180" ,
621 which would rotate
622 the scene to behind the observer.
623 .SH FILES
624 .TF /lib/map/[1-4]??
625 .TP
626 .B /lib/map/[1-4]??
627 World Data Bank II, for
628 .B -f
629 .TP
630 .B /lib/map/*
631 maps for
632 .B -m
633 .TP
634 .B /lib/map/*.x
635 map indexes
636 .TP
637 .B mapd
638 Map driver program
639 .SH SOURCE
640 .B \*9/src/cmd/map
641 .SH "SEE ALSO"
642 .IR map (7),
643 .MR plot (1)
644 .SH DIAGNOSTICS
645 `Map seems to be empty'\(ema coarse survey found
646 zero extent within the
647 .B -l
648 and
649 .BR -w
650 bounds; for maps of limited extent
651 the grid resolution,
652 .IR res ,
653 or the limits may have to be refined.
654 .SH BUGS
655 Windows (option
656 .BR -w )
657 cannot cross the Date Line.
658 No borders appear along edges arising from
659 visibility limits.
660 Segments that cross a border are dropped, not clipped.
661 Excessively large scale or
662 .B -d
663 setting may cause long line segments to be dropped.
664 .I Map
665 tries to draw grid lines dotted and
666 .B -t
667 tracks dot-dashed.
668 As very few plotting filters properly support
669 curved textured lines, these lines are likely to
670 appear solid.
671 The west-longitude-positive convention
672 betrays Yankee chauvinism.
673 .I Gilbert
674 should be a map from sphere to sphere, independent of
675 the mapping from sphere to plane.