31:
452:
471:
infrastructure works. The parameters defining each Snake
Projection are tailored for the specific project; the most typical use is with large-scale linear engineering projects such as rail infrastructure, however the projection is equally applicable to any application requiring a low distortion grid
479:
The principal advantage of the projection is that, for the corridor defining the design space, distances measured on the ground have a nearly one to one relationship with distances in coordinate space (i.e. no scale factor need be applied to convert between distances in grid and distances on the
883:
491:
The Snake
Projection is suited for engineering purposes due to its low distortion characteristics. An example of its differentiation from mapping grids is the 60m increase in length of the London to Birmingham section of the
829:
675:
552:
geodetic coordinate system database features several snake projection definitions through the NTv2 approach. Other implementations include those published through the SnakeGrid organisation.
783:
472:
along a linear route (for example pipelines and roads). The name of the projection is derived from the sinuous snake-like nature of the projects it may be designed for. Typical
480:
ground). The length of the applicable corridor is variable on a project basis, however when required the projection can extend over several hundreds of kilometres to achieve
923:
632:
860:
758:
818:
655:
532:
and grid coordinates, however the method of technical implementation can vary. One method of implementing a Snake
Projection is to define using an
508:
The Snake
Projection is the engineering coordinate system used for a significant proportion of primary rail routes in the UK, including that of the
476:
distance distortion characteristics of a Snake
Projection are minimal over the whole route within approximately 20 kilometres of the centre line.
390:
212:
496:
rail line, purely due to the more accurate grid representation compared to the length when using the national mapping coordinate system
380:
348:
791:
488:
along the route. The main disadvantage is that away from the design corridor the distortion of the projection is not controlled.
358:
984:
669:
338:
725:
954:
318:
119:
418:
913:
622:
852:
747:
586:
Iliffe, J. C.; Arthur, J. V.; Preston, C. (2007). "The Snake
Projection: A Customised Grid for Rail Projects".
204:
220:
817:
James Turner; Chris
Preston; Richard Winthrop; Ian Thatcher; Peter Swales; Jamie Finney (30 November 2020).
1022:
1032:
891:
460:
183:
1012:
150:
97:
561:
288:
248:
268:
784:"Use of Global Navigation Satellite Systems (GNSS) in land surveying and mapping, 3rd edition"
455:
Generating a trend line of zero distortion that follows the route of a long and linear project
497:
411:
328:
78:
661:
529:
513:
228:
178:
104:
8:
537:
468:
140:
88:
1027:
919:
717:
603:
517:
485:
60:
30:
536:
geodetic transformation coupled with a standard parameterised map projection (such as
816:
665:
607:
440:
160:
145:
721:
1017:
976:
709:
595:
481:
404:
155:
713:
944:
473:
436:
368:
135:
109:
1006:
819:"Advances in Engineering Survey Grid Transformations for Rail Infrastructure"
599:
464:
93:
443:
for realizing low distortion throughout long linear engineering projects.
50:
697:
566:
540:); this is increasing in popularity due to better compatibility with
129:
55:
451:
308:
125:
114:
516:
the distortion in the Snake
Projection used is no greater than 20
188:
45:
22:
512:
London to
Birmingham high speed line. For the London to Glasgow
884:"HS2 becomes fifth project this year to adopt SnakeGrid system"
298:
258:
196:
698:"The development and analysis of quasi-linear map projections"
627:
83:
949:
549:
533:
385:
278:
467:
to provide a continuous low distortion projection for the
823:
545:
541:
509:
493:
657:
585:
520:within 5 kilometres of either side of the track.
459:The Snake Projection was originally developed by
1004:
528:The Snake Projection algorithm converts between
702:Cartography and Geographic Information Science
412:
757:. Society of Chartered Surveyors Ireland.
419:
405:
386:Spatial Reference System Identifier (SRID)
381:International Terrestrial Reference System
911:
792:Royal Institution of Chartered Surveyors
653:
450:
620:
1005:
695:
987:from the original on 24 February 2023
957:from the original on 24 February 2023
812:
810:
850:
745:
391:Universal Transverse Mercator (UTM)
353:European Terrestrial Ref. Sys. 1989
13:
807:
764:from the original on 22 April 2023
748:"Map Projections and Scale Factor"
635:from the original on 22 April 2023
263:Ordnance Survey Great Britain 1936
229:Discrete Global Grid and Geocoding
120:Horizontal position representation
16:Map projection for linear projects
14:
1044:
945:"EPSG Geodetic Parameter Dataset"
832:from the original on 29 June 2022
523:
912:Uren, John; Price, Bill (2010).
179:Global Nav. Sat. Systems (GNSSs)
29:
969:
937:
926:from the original on 2018-02-07
905:
881:
863:from the original on 2018-02-05
728:from the original on 2023-04-22
678:from the original on 2018-02-07
343:N. American Vertical Datum 1988
875:
844:
776:
739:
689:
647:
614:
579:
373:Internet link to a point 2010
303:Geodetic Reference System 1980
221:Quasi-Zenith Sat. Sys. (QZSS)
1:
853:"Corridor Projections Solved"
714:10.1080/15230406.2017.1325332
572:
439:typically used as the planar
363:Chinese obfuscated datum 2002
977:"FREQUENTLY ASKED QUESTIONS"
313:Geographic point coord. 1983
7:
918:(5 ed.). Basingstoke:
555:
273:Systema Koordinat 1942 goda
10:
1049:
446:
333:World Geodetic System 1984
795:. 16 May 2023. p. 34
746:SCSI (26 November 2020).
461:University College London
323:North American Datum 1983
293:South American Datum 1969
623:"Working with SnakeGrid"
600:10.1179/003962607X165041
503:
184:Global Pos. System (GPS)
151:Spatial reference system
915:Surveying for Engineers
654:Reynolds, John (2011).
621:Gibbons, Chris (2023).
562:List of map projections
696:Iliffe, J. C. (2017).
548:software. The global
456:
662:John Wiley & Sons
498:British National Grid
454:
79:Geographical distance
514:West Coast Main Line
253:Sea Level Datum 1929
105:Geodetic coordinates
1023:Rail infrastructure
851:XYHT (2015-01-15).
538:Transverse Mercator
469:West Coast Mainline
283:European Datum 1950
241:Standards (history)
141:Reference ellipsoid
89:Figure of the Earth
920:Palgrave Macmillan
457:
161:Vertical positions
1033:Civil engineering
859:. Flatdog Media.
671:978-0-471-48535-3
518:parts per million
486:parts per million
441:coordinate system
429:
428:
377:
376:
156:Spatial relations
146:Satellite geodesy
101:
1040:
997:
996:
994:
992:
973:
967:
966:
964:
962:
941:
935:
934:
932:
931:
909:
903:
902:
900:
898:
879:
873:
872:
870:
868:
848:
842:
841:
839:
837:
814:
805:
804:
802:
800:
788:
780:
774:
773:
771:
769:
763:
752:
743:
737:
736:
734:
733:
693:
687:
686:
684:
683:
651:
645:
644:
642:
640:
618:
612:
611:
583:
484:of less than 20
435:is a continuous
433:Snake Projection
421:
414:
407:
245:
244:
224:
216:
208:
200:
192:
132:
91:
33:
19:
18:
1048:
1047:
1043:
1042:
1041:
1039:
1038:
1037:
1013:Map projections
1003:
1002:
1001:
1000:
990:
988:
975:
974:
970:
960:
958:
943:
942:
938:
929:
927:
910:
906:
896:
894:
880:
876:
866:
864:
849:
845:
835:
833:
826:Learning Legacy
815:
808:
798:
796:
786:
782:
781:
777:
767:
765:
761:
750:
744:
740:
731:
729:
694:
690:
681:
679:
672:
652:
648:
638:
636:
619:
615:
584:
580:
575:
558:
526:
506:
482:grid distortion
449:
425:
396:
395:
242:
234:
233:
222:
214:
206:
198:
190:
174:
166:
165:
124:
74:
66:
65:
41:
17:
12:
11:
5:
1046:
1036:
1035:
1030:
1025:
1020:
1015:
999:
998:
968:
936:
904:
874:
843:
806:
775:
738:
708:(3): 270–283.
688:
670:
660:(2 ed.).
646:
613:
594:(304): 90–99.
577:
576:
574:
571:
570:
569:
564:
557:
554:
525:
524:Implementation
522:
505:
502:
474:map projection
448:
445:
437:map projection
427:
426:
424:
423:
416:
409:
401:
398:
397:
394:
393:
388:
383:
375:
374:
371:
365:
364:
361:
355:
354:
351:
345:
344:
341:
335:
334:
331:
325:
324:
321:
315:
314:
311:
305:
304:
301:
295:
294:
291:
285:
284:
281:
275:
274:
271:
265:
264:
261:
255:
254:
251:
243:
240:
239:
236:
235:
232:
231:
226:
218:
210:
202:
194:
186:
181:
175:
172:
171:
168:
167:
164:
163:
158:
153:
148:
143:
138:
136:Map projection
133:
122:
117:
112:
110:Geodetic datum
107:
102:
86:
81:
75:
72:
71:
68:
67:
64:
63:
58:
53:
48:
42:
39:
38:
35:
34:
26:
25:
15:
9:
6:
4:
3:
2:
1045:
1034:
1031:
1029:
1026:
1024:
1021:
1019:
1016:
1014:
1011:
1010:
1008:
986:
982:
981:Snakegrid.org
978:
972:
956:
952:
951:
946:
940:
925:
921:
917:
916:
908:
893:
889:
885:
878:
862:
858:
854:
847:
831:
827:
825:
820:
813:
811:
794:
793:
785:
779:
760:
756:
749:
742:
727:
723:
719:
715:
711:
707:
703:
699:
692:
677:
673:
667:
663:
659:
658:
650:
634:
630:
629:
624:
617:
609:
605:
601:
597:
593:
589:
588:Survey Review
582:
578:
568:
565:
563:
560:
559:
553:
551:
547:
543:
539:
535:
531:
521:
519:
515:
511:
501:
499:
495:
489:
487:
483:
477:
475:
470:
466:
462:
453:
444:
442:
438:
434:
422:
417:
415:
410:
408:
403:
402:
400:
399:
392:
389:
387:
384:
382:
379:
378:
372:
370:
367:
366:
362:
360:
357:
356:
352:
350:
347:
346:
342:
340:
337:
336:
332:
330:
327:
326:
322:
320:
317:
316:
312:
310:
307:
306:
302:
300:
297:
296:
292:
290:
287:
286:
282:
280:
277:
276:
272:
270:
267:
266:
262:
260:
257:
256:
252:
250:
247:
246:
238:
237:
230:
227:
225:
219:
217:
211:
209:
203:
201:
197:BeiDou (BDS)
195:
193:
187:
185:
182:
180:
177:
176:
170:
169:
162:
159:
157:
154:
152:
149:
147:
144:
142:
139:
137:
134:
131:
127:
123:
121:
118:
116:
113:
111:
108:
106:
103:
99:
98:circumference
95:
90:
87:
85:
82:
80:
77:
76:
70:
69:
62:
59:
57:
54:
52:
49:
47:
44:
43:
37:
36:
32:
28:
27:
24:
21:
20:
989:. Retrieved
980:
971:
959:. Retrieved
948:
939:
928:. Retrieved
914:
907:
895:. Retrieved
887:
877:
865:. Retrieved
856:
846:
834:. Retrieved
822:
797:. Retrieved
790:
778:
766:. Retrieved
754:
741:
730:. Retrieved
705:
701:
691:
680:. Retrieved
656:
649:
637:. Retrieved
626:
616:
591:
587:
581:
530:geographical
527:
507:
490:
478:
465:Network Rail
458:
432:
430:
173:Technologies
128: /
40:Fundamentals
991:24 February
961:24 February
768:24 February
639:24 February
51:Geodynamics
1007:Categories
930:2018-02-06
897:5 February
867:5 February
732:2018-11-26
682:2018-02-06
573:References
1028:Surveying
608:128833605
567:Surveying
130:Longitude
56:Geomatics
985:Archived
955:Archived
924:Archived
861:Archived
830:Archived
759:Archived
726:Archived
722:67328277
676:Archived
633:Archived
556:See also
309:ISO 6709
207:(Europe)
205:Galileo
191:(Russia)
189:GLONASS
126:Latitude
115:Geodesic
73:Concepts
1018:Geodesy
447:Details
369:Geo URI
339:NAVD 88
249:NGVD 29
223:(Japan)
215:(India)
199:(China)
61:History
46:Geodesy
23:Geodesy
836:24 May
799:5 June
720:
668:
606:
359:GCJ-02
349:ETRS89
329:WGS 84
319:NAD 83
299:GRS 80
259:OSGB36
213:NAVIC
94:radius
882:UCL.
787:(PDF)
762:(PDF)
751:(PDF)
718:S2CID
628:CICES
604:S2CID
504:Usage
289:SAD69
269:SK-42
84:Geoid
993:2023
963:2023
950:EPSG
899:2018
888:CEGE
869:2018
857:XYHT
838:2023
801:2023
770:2023
755:SCSI
666:ISBN
641:2023
550:EPSG
544:and
534:NTv2
463:and
431:The
279:ED50
96:and
892:UCL
824:HS2
710:doi
596:doi
546:GIS
542:CAD
510:HS2
494:HS2
1009::
983:.
979:.
953:.
947:.
922:.
890:.
886:.
855:.
828:.
821:.
809:^
789:.
753:.
724:.
716:.
706:45
704:.
700:.
674:.
664:.
631:.
625:.
602:.
592:39
590:.
500:.
995:.
965:.
933:.
901:.
871:.
840:.
803:.
772:.
735:.
712::
685:.
643:.
610:.
598::
420:e
413:t
406:v
100:)
92:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
