.TH LATCMP 1
.SH NAME
latcmp \- compare latitudes
.SH SYNOPSIS
.B latcmp
[
.B -m
] [
.B -l
.I lat lng
] ... [
.I file ...
]
.SH DESCRIPTION
.I Latcmp
computes the distance in meters between two points on the earth using
Thaddeus Vincenty's formula using the WGS-84 parameters.  Divergent
cases are approximated with the Haversine formula.  The default starting
point is taken from
.BR /lib/sky/here 
and can be overridden with the
.B -l
option.  A second
.B -l
option specifies the comparison point.
Files passed on the command line are expected to have one comparison
point per line.  Leading and trailing text is ignored.  A point consists
of two floating-point numbers, representing the latitude and longitude in
degrees, separated by whitespace.  The sign is negative for latitude South
of the equator, and longitude West of the Prime Meridian.
.P
For each point after the first, the geodesic distance in meters to the first is computed.
The output is the input line (or the point, if specified on the command line)
a tab and the distance between that point and the first.  The
.B -m
flag only prints the point closest to the first.  The
.B -q
flag prints only the geodesic distance.
.SH SOURCE
.B /sys/src/cmd/latcmp.c