GreatCircle

GreatCircle calculates:

short and long path distances between two locations on Earth;
initial and final bearing;
location of sub-reflective points for single-hop and multi-hops radio propagation modes.

The calculations are done either:

assuming a spherical Earth (Haversine formulas are used). Precision on the distance is about 0.3%;
assuming a spheroid Earth (Vincenty formulas are used). Precision on the distance is in the millimeter range. 55 reference ellipsoids types are known.

GreatCircle can be used using a graphical user interface or through command line.

Graphical User Interface

The interface of GreatCircle is shown below:

The user needs to precise start and end points locations through either latitude/longitude or Maidenhead locator. After pressing the "Calculate" button, the short path and long path distances are shown as well as initial and final bearings. The calculation is done by default for a spherical Earth but a reference ellipsoid can be precised.

Command Line Interface

Additionaly, the tool can be used in command line mode by invoking the program GreatCircle.exe.
Example:

GreatCircle.exe --longitude1 "0 0 0E" --latitude1 "10 0N"  --longitude2 "120° 15' E" --latitude2 -25.3 --hops 2]]>

The output of this command is:

Help on the command line options are available by invoking:

>GreatCircle.exe --help

Download

Current version is 1.0.0.0.

GreatCircle binary and source can be downloaded through anonymous SVN at the following address:
https://anonsvn.loudet.org/GreatCircle/tags/

GreatCircle has been developped in C# under Visual Studio Express 2008.
It has been tested under Linux Ubuntu 9.10/Mono 2.4.2.3, and under Windows XP/.NET 2.0.

Changelog

Installation

Under Windows, it is necessary to install :

either .NET 2.0 Redistributable Package, available at: .NET 2.0.
either Mono 2.4 or above, available at: Mono.

Under Linux, it is necessary to install :

Mono 2.4 or above, available at: Mono.

Help (for the command line interface version)

 --latitude1  | --locator1 
              --longitude2  --latitude2  | --locator2 
              [--hops ] [--ellipsoid ]
              [--pairs ] [--precision ] [--decimal]
    Determines the distace between start and end points.

    Options:
    longitude1 String or real longitude value of the start point.
               Positive values in the eastern hemisphere.
    latitude1  String or real latitude value of the start point.
               Positive values in the northern hemisphere.
    locator1   Locator value of the start point.
    longitude2 String or real longitude value of the end point.
               Positive values in the eastern hemisphere.
    latitude2  String or real latitude value of the end point.
               Positive values in the northern hemisphere.
    locator2   Locator value of the end point.
    hops       Number of hop positions to calculate, from 0 to 20. Default is 1.
    ellipsoid  Reference ellipsoid to consider. Known ellipsoids are listed below.
               If not set, a spherical Earth is assumed and Haversine formulas are used.
               Precision on the distance is about 0.3%.
               If set, a spheroid Earth and Vincenty formulas are used.
               Precision on the distance is in the millimeter range
    pairs      Number of locator pairs used to represent locators.
               From 1 to 6. Default is 3 (field+square+subsquare).
    precision  Number of digits used to represent the values decimal parts
               From 0 to 15. Default is 2.
    decimal    Displays latitude/longitude as decimal degrees, instead of DMS.

  GreatCircle --longitude1  --latitude1  | --locator1 
              --bearing  --distance 
              [--hops ] [--ellipsoid ]
              [--pairs ] [--precision ] [--decimal]
    Determines the end point at the specified distance and bearing from the start point.

    Options:
    longitude1 String or real longitude value of the start point.
               Positive values in the eastern hemisphere.
    latitude1  String or real latitude value of the start point.
               Positive values in the northern hemisphere.
    locator1   Locator value of the start point.
    bearing    Initial bearing from start point to end point. In degrees.
    distance   Distance in m from start point to end point.
    hops       Number of hop positions to calculate, from 0 to 20. Default is 1.
    ellipsoid  Reference ellipsoid to consider. Known ellipsoids are listed below.
               If not set, a spherical Earth is assumed and Haversine formulas are used.
               Precision on the distance is about 0.3%.
               If set, a spheroid Earth and Vincenty formulas are used.
               Precision on the distance is in the millimeter range
    pairs      Number of locator pairs used to represent locators.
               From 1 to 6. Default is 3 (field+square+subsquare).
    precision  Number of digits used to represent the values decimal parts
               From 0 to 15. Default is 2.
    decimal    Displays latitude/longitude as decimal degrees, instead of DMS.

KNOWN ELLIPSOIDS: :
grs67: GRS 67 (IUGG 1967)
grs75: GRS 75 (IUGG 1975)
grs80: GRS 80 (IUGG 1980)
merit: MERIT 1983
intl: Int'l 1924
newintl: New International (1967)
iau76: IAU 1976
apl4.9: Appl. Physics. 1965
nwl9d: Naval Weapons Lab., 1965
clarke66: Clarke 1866
clarke80: Clarke 1880
clarke80mod: Clarke 1880 mod.
nad27: NAD 27
nad83: NAD 83
timbalai: Timbalai
maupertuis: Maupertuis 1738
plessis: Plessis 1817 (France)
helmert: Helmert 1906
hayford: International 1909 (Hayford)
lerch: Lerch 1979
krassovsky: Krassovsky 1940
kaula: Kaula 1961
australian: Australian National (1969)
southamerican: South American (1969)
cpm: Comm. des Poids et Mesures 1799
delambre: Delambre 1810 (Belgium)
engelis: Engelis 1985
iers89: IERS (1989)
iers03: IERS (2003)
andrae: Andrae 1876 (Den., Iclnd.)
wgs60: WGS 60
wgs66: WGS 66
wgs72: WGS 72
wgs84: WGS 84
airy: Airy (1830)
modairy: Modified Airy
hough: Hough  (1956)
seasia: Southeast Asia
walbeck: Walbeck
fischer60: Fisher (Mercury Datum) 1960
fischer60m: Modified Fisher 1960
fischer68: Fisher 1968
sphere: Normal Sphere (r=6370997)
indonesian: Indonesian (1974)
bessel: Bessel 1841
besselnamibia: Bessel 1841 (Namibia)
everest30: Everest 1830
everest48: Everest 1948
everest56: Everest 1956
everest69: Everest 1969
everestpk: Everest (Pakistan)
everestss: Everest (Sabah & Sarawak)
everestmod: Modified Everest (Malaya) Revised Kertau
sgs85: Soviet Geodetic System 85
ats77: ATS77
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