pickax.distaz

Module Contents

Classes

DistAz

c c Subroutine to calculate the Great Circle Arc distance c between two sets of geographic coordinates c c Equations take from Bullen, pages 154, 155 c c T. Owens, September 19, 1991 c Sept. 25 – fixed az and baz calculations c P. Crotwell, Setember 27, 1995 Converted to c to fix annoying problem of fortran giving wrong answers if the input doesn’t contain a decimal point.

Functions

main

API

class pickax.distaz.DistAz(lat1, lon1, lat2, lon2)

c c Subroutine to calculate the Great Circle Arc distance c between two sets of geographic coordinates c c Equations take from Bullen, pages 154, 155 c c T. Owens, September 19, 1991 c Sept. 25 – fixed az and baz calculations c P. Crotwell, Setember 27, 1995 Converted to c to fix annoying problem of fortran giving wrong answers if the input doesn’t contain a decimal point.

H. P. Crotwell, September 18, 1997 Java version for direct use in java programs. * * C. Groves, May 4, 2004 * Added enough convenience constructors to choke a horse and made public double * values use accessors so we can use this class as an immutable

H.P. Crotwell, May 31, 2006 Port to python, thus adding to the great list of languages to which distaz has been ported from the origin fortran: C, Tcl, Java and now python and I vaguely remember a perl port. Long live distaz!

Initialization

c lat1 => Latitude of first point (+N, -S) in degrees c lon1 => Longitude of first point (+E, -W) in degrees c lat2 => Latitude of second point c lon2 => Longitude of second point c c getDelta() => Great Circle Arc distance in degrees c getAz() => Azimuth from pt. 1 to pt. 2 in degrees c getBaz() => Back Azimuth from pt. 2 to pt. 1 in degrees

rad = None

c c scolat and ecolat are the geocentric colatitudes c as defined by Richter (pg. 318) c c Earth Flattening of 1/298.257 take from Bott (pg. 3) c

elon = None

c c a - e are as defined by Bullen (pg. 154, Sec 10.2) c These are defined for the pt. 1 c

k = None

c c aa - ee are the same as a - e, except for pt. 2 c

kk = None

c c Bullen, Sec 10.2, eqn. 4 c

delta = None

c c Bullen, Sec 10.2, eqn 7 / eqn 8 c c pt. 1 is unprimed, so this is technically the baz c c Calculate baz this way to avoid quadrant problems c

baz = None

c c Bullen, Sec 10.2, eqn 7 / eqn 8 c c pt. 2 is unprimed, so this is technically the az c

az = None

c c Make sure 0.0 is always 0.0, not 360. c

getDelta()

getDistanceKm()

getDistanceDeg()

getAz()

getBaz()

static degreesToKilometers(degrees)

static kilometersToDegrees(kilometers)

exception pickax.distaz.Usage(msg)

Bases: Exception

pickax.distaz.main(argv=None)