|
|
|
|
|||||
|
||||||
Subject: leg56. Chart vs formulas
From: Andres Ruiz (aruiz@XXX.XXX)
Date: Fri Jul 16 1999 - 05:15:23 EDT
In coastal navigation I use the charts for navigation, but when the distance is outside of the chart, for me is easier to use a calculator with trigonometric functions in order to obtain the DR position, or to find the rhumb to a point.
I've compared the Mid-Latitude Sailing, the RhumbLine, and the Great Circle Sailing of the point 2) of the Leg 56, and here are the results.
The distance is a great one, because of this the best method is to divide the GC track in small legs, and sail between them by a rhumbline, from a waypoint to another.
Lat1
Lon1
R
d
Lat2
Lon2
LatitudMed
R, d ?
-42.6633
-98.8583
124.3904
1487.5287
-56.6667
-67.25
Loxodromica
R, d ?
-42.6633
-98.8583
124.5705
1480.7388
-56.6667
-67.25
Ortodromica
R, d ?
-42.6633
-98.8583
135.9026
1466.8856
-56.6667
-67.25
Ortodromica
WayPoint
-42.6633
-98.8583
135.9026
506.8132
-48.4098
-90
Ortodromica
WayPoint
-48.4098
-90
129.5663
245.2815
-50.9095
-85
Ortodromica
WayPoint
-50.9095
-85
125.7533
222.4828
-52.9731
-80
Ortodromica
WayPoint
-52.9731
-80
121.8148
204.0477
-54.6645
-75
Ortodromica
WayPoint
-54.6645
-75
117.7777
189.2925
-56.0348
-70
Ortodromica
WayPoint
-56.0348
-70
113.6634
177.6471
-57.1245
-65
Ortodromica
WayPoint
-57.1245
-65
289.4892
78.6791
-56.6667
-67.25
If you want, in the address below, you can find the algorithm for mercator sailing and rhumbLines. The titles are in Spanish, but the algorithm are mathematics, universal language.
http://www.geocities.com/CapeCanaveral/Runway/3568/index.html [Navigation] [Mercator sailing]
I translate some words for anyone interested:
Rumbo y distancia Course and distance
Posicion. La estima Dead reckoning
Loxodromica Loxodromic or rhumbLines
Partes meridionales Meridional parts
I don't know what is the difference between mercator sailing and rhumbline, for me is the same ¿?
Andrés Ruiz
e-mail: aruiz@XXX.XXX
http://www.geocities.com/CapeCanaveral/Runway/3568/index.html
|