gridcal -- compute the great-circle distance between two grid locators ====================================================================== `gridcal` computes the short-path great-circle distance between two grid locators. The Grid Locator System divides Earth into a series of rectangles identified by a combination of letters and numbers, so that the approximate position of a point can be expressed with a short identifier like IO91vl. Usage: gridcal [ []] If `gridcal` is given only one locator, it prints on output the latitude and longitude of the centre of the corresponding grid square: gridcal IO91vl IO91vl 51.4792 -0.208333 0.898481 -0.0036361 The first two numbers are latitute and longitude in degree, the last two are the corresponding values in radians. With two locators provided as input, `gridcal` prints on output the two locators and their great-circle distance, both in km and miles: gridcal IO91vl JN65od IO91vl JN65od 1213.71 754.164 If `gridcal` is given as third numerical argument, that number is considered a "power" value in Watts, and `gridcal` will print on output a longer line containing the two locators, the distance in km and miles, the power value, and the corresponding km/W and miles/W: gridcal IO91vl JN65od 1.2 IO91vl JN65od 1213.71 754.164 1.2 1011.42 628.47 The latter can be useful to check if a QSO with another ham radio station qualifies for one of the thousand miles per Watt awards. `getgrid` -- compute the grid locator associated to lat-long coordinates ======================================================================== `getgrid` is a simple tool to compute the grid locator associated to a latitude/longitude pair. The coordinates must be in degrees. Usage: getgrid Example: getgrid Dependencies ============ `gridcal` is written in ANSI C has no dependencies. License ======= `gridcal` is free software. It can be used, modified, distributed under the terms of the ISC License. See the file LICENSE for more information.