171:. Viewsheds and isovists are sometimes said to be equivalent, however others have found differences between them. It has been argued that isovists are more focused on representing space whereas viewsheds are about the visibility of features. Also, the problems they are used in have different scales. Planners use viewsheds where terrain heights come into play whereas architects do not typically take that into account with isovists.
74:. In urban planning, for example, viewsheds tend to be calculated for areas of particular scenic or historic value that are deemed worthy of preservation against development or other change. Viewsheds are often calculated for public areas — for example, from public roadways, public parks, or high-rise buildings. The preservation of viewsheds is frequently a goal in the designation of
20:
124:
Viewshed calculation on a large DEM is costly from a computational point of view. This cost is much higher when calculating the viewshed for all the points of the DEM, also called total-viewshed. A faster algorithm for computing the total-viewshed of large DEMs was proposed on.
106:
and therefore the viewshed may be represented with non-integer values. Viewsheds for multiple points, lines, or areas may have counts or fractional values for queries involving "how much" or "how many" (e.g., how much of a highway is visible?).
102:) with a value of 1 (or "true") indicates that the viewpoint is visible from that cell, while a value of 0 (false) indicates that the viewpoint is not visible. In certain disciplines, such as radio communications, "visibility" may be
121:
A terrain can be represented using a regular grid of points called
Digital Elevation Model (DEM). Where each point of the DEM is represented by its coordinates X, Y and its height Z.
47:
or obstructed by terrain and other features (e.g., buildings, trees). Conversely, it can also refer to area from which an object can be seen. A viewshed is not necessarily "
604:
284:. Washington, DC: U.S. Department of Transportation, Federal Highway Administration, Office of Environmental Policy. September 1990. pp. 26–33, 123.
196:
is the area from which a development or other structure is theoretically visible. It is usually represented as a map using color to indicate visibility.
609:
480:
Cervilla, A; Tabik, S; Vías, J; Mérida, M; Romero, F (2016). "Total 3D‐viewshed Map: Quantifying the
Visible Volume in Digital Elevation Models".
215:
that are visible from a particular area. A cumulative zone of visual influence is used to define the cumulative effects of many developments.
199:
Zones of visual influence are used to identify the parts of a landscape that will be affected by a development. They are of particular use to
299:
Tabik, S; Cervilla, A; Zapata, E; Romero, F (2015). "Efficient data structure and highly scalable algorithm for total-viewshed computation".
98:
indicating the visibility of a viewpoint for or from an area of interest. In a binary representation, a cell (shown graphically as a
570:
536:
204:
599:
181:
Total-viewshed map refers to the map, where each point represents the number of Km² visible at that point in the DEM.
231:
40:
200:
28:
24:
55:
to indicate where a specific combination of transmitter, antenna, and terrain allow reception of signal.
39:
is the geographical area that is visible from a location. It includes all surrounding points that are in
251:
31:(red) overlaid on an elevation map (other colors) – areas in red are visible from the landing site
276:
308:
83:
52:
507:
420:
324:
75:
566:
560:
532:
526:
462:
116:
59:
497:
489:
454:
412:
355:
316:
246:
158:
71:
48:
401:"From isovists to visibility graphs: a methodology for the analysis of architectural space"
184:
The 3D-viewshed of a point (X,Y) of the DEM consists of the visible space from that point.
256:
145:
343:
528:
Wind Energy - The Facts: "A Guide to the
Technology, Economics and Future of Wind Power"
312:
241:
63:
593:
140:
511:
424:
328:
212:
168:
133:
Clifford Tandy is credited with coining the term "viewshed" in 1967 by analogy to
320:
301:
IEEE Journal of
Selected Topics in Applied Earth Observations and Remote Sensing
103:
95:
67:
400:
442:
135:
79:
466:
208:
19:
374:
502:
493:
458:
359:
236:
164:
44:
525:
Association, European Wind Energy
European Wind Energy (2012-05-04).
342:
Nijhuis, Steffen; van
Lammeren, Ron; Antrop, Marc (September 2011).
416:
167:
are a closely related concept that is more common in the study of
99:
18:
174:
The area from which a structure can be seen may be called the "
219:
178:." This can be referred to as the viewshed as well, though.
207:. Zones of visual influence have been used extensively in
43:
with that location and excludes points that are beyond the
211:
development. A map will be created showing the number of
399:Turner, A; Doxa, M; O'Sullivan, D; Penn, A (2001).
294:
292:
405:Environment and Planning B: Planning and Design
344:"Exploring the Visual Landscape - Introduction"
436:
434:
203:in determining visual intrusion as part of an
278:Visual Impact Assessment for Highway Projects
175:
8:
559:Morris, Peter; Therivel, Riki (2009-03-05).
218:Zones of visual influence are created using
562:Methods of Environmental Impact Assessment
443:"Mapping landscape openness with isovists"
501:
143:cites a use of the term from 1970 in the
51:" to humans; the same concept is used in
16:Geographical area visible from a location
268:
111:Viewshed and total-viewshed computation
605:Urban studies and planning terminology
7:
286:Publication number FHWA-HI-88-054.
14:
441:Weitkamp, Gerd (September 2011).
373:Barrett, Grant (March 27, 2006).
157:Viewsheds are a specific type of
94:A viewshed can be represented by
610:Environmental impact assessment
205:environmental impact assessment
58:Viewsheds are commonly used in
1:
565:. Routledge. pp. 450–.
447:Research in Urbanism Series
348:Research in Urbanism Series
321:10.1109/jstars.2014.2326252
626:
531:. Routledge. p. 540.
114:
62:, which is of interest to
232:Computational archaeology
257:Euclidean influence zone
194:zone of visual influence
188:Zone of visual influence
176:Zone of Visual Influence
32:
29:Mars Exploration Rover
600:Topography techniques
252:Visibility (geometry)
22:
201:landscape architects
139:. The lexicographer
84:community separators
53:radio communications
482:Transactions in GIS
313:2015IJSTA...8..304T
494:10.1111/tgis.12216
459:10.7480/rius.2.213
360:10.7480/rius.2.205
33:
117:Viewshed analysis
27:on Mars from the
617:
584:
583:
581:
579:
556:
550:
549:
547:
545:
522:
516:
515:
505:
477:
471:
470:
438:
429:
428:
396:
390:
389:
387:
385:
379:A Way with Words
370:
364:
363:
339:
333:
332:
296:
287:
285:
283:
273:
247:Visibility graph
159:visibility graph
153:Related concepts
72:military science
60:terrain analysis
23:Viewshed of the
625:
624:
620:
619:
618:
616:
615:
614:
590:
589:
588:
587:
577:
575:
573:
558:
557:
553:
543:
541:
539:
524:
523:
519:
479:
478:
474:
440:
439:
432:
398:
397:
393:
383:
381:
372:
371:
367:
341:
340:
336:
298:
297:
290:
281:
275:
274:
270:
265:
228:
190:
155:
146:Oakland Tribune
131:
119:
113:
92:
17:
12:
11:
5:
623:
621:
613:
612:
607:
602:
592:
591:
586:
585:
571:
551:
537:
517:
488:(3): 304–310.
472:
430:
411:(1): 103–121.
391:
365:
334:
307:(1): 304–310.
288:
267:
266:
264:
261:
260:
259:
254:
249:
244:
242:Scenic highway
239:
234:
227:
224:
189:
186:
154:
151:
130:
127:
115:Main article:
112:
109:
91:
90:Representation
88:
64:urban planning
15:
13:
10:
9:
6:
4:
3:
2:
622:
611:
608:
606:
603:
601:
598:
597:
595:
574:
572:9780203892909
568:
564:
563:
555:
552:
540:
538:9781136548598
534:
530:
529:
521:
518:
513:
509:
504:
499:
495:
491:
487:
483:
476:
473:
468:
464:
460:
456:
452:
448:
444:
437:
435:
431:
426:
422:
418:
417:10.1068/b2684
414:
410:
406:
402:
395:
392:
380:
376:
369:
366:
361:
357:
353:
349:
345:
338:
335:
330:
326:
322:
318:
314:
310:
306:
302:
295:
293:
289:
280:
279:
272:
269:
262:
258:
255:
253:
250:
248:
245:
243:
240:
238:
235:
233:
230:
229:
225:
223:
221:
216:
214:
213:wind turbines
210:
206:
202:
197:
195:
187:
185:
182:
179:
177:
172:
170:
166:
162:
160:
152:
150:
148:
147:
142:
141:Grant Barrett
138:
137:
128:
126:
122:
118:
110:
108:
105:
104:probabilistic
101:
97:
89:
87:
85:
81:
77:
73:
69:
65:
61:
56:
54:
50:
46:
42:
41:line-of-sight
38:
30:
26:
21:
576:. Retrieved
561:
554:
542:. Retrieved
527:
520:
485:
481:
475:
450:
446:
408:
404:
394:
382:. Retrieved
378:
368:
351:
347:
337:
304:
300:
277:
271:
217:
198:
193:
191:
183:
180:
173:
169:architecture
163:
156:
144:
134:
132:
123:
120:
93:
57:
36:
34:
25:Gusev crater
578:15 February
503:10630/29115
96:raster data
80:green belts
68:archaeology
594:Categories
375:"viewshed"
263:References
76:open space
467:1879-8217
384:March 10,
209:wind farm
136:watershed
512:29701632
425:17332950
329:23232474
226:See also
165:Isovists
37:viewshed
453:: 208.
309:Bibcode
237:Isovist
222:tools.
129:History
78:areas,
49:visible
45:horizon
569:
544:8 July
535:
510:
465:
423:
354:: 30.
327:
82:, and
70:, and
508:S2CID
421:S2CID
325:S2CID
282:(PDF)
100:pixel
580:2013
567:ISBN
546:2019
533:ISBN
463:ISSN
386:2015
498:hdl
490:doi
455:doi
413:doi
356:doi
317:doi
220:GIS
596::
506:.
496:.
486:21
484:.
461:.
449:.
445:.
433:^
419:.
409:28
407:.
403:.
377:.
350:.
346:.
323:.
315:.
303:.
291:^
192:A
161:.
149:.
86:.
66:,
35:A
582:.
548:.
514:.
500::
492::
469:.
457::
451:2
427:.
415::
388:.
362:.
358::
352:2
331:.
319::
311::
305:8
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.