There are a number of approaches to solve the inverse geodesic problem, this post provides the IDL code to use Newton’s method as described by Karney (2012) in ‘Algorithms for geodesics‘.
Chris blew my mind this morning when he showed me what happens if you use negative numbers to index an array in IDL (in versions lower than 8!). I would argue that it gives something that you don’t want, this is how you fix it.
A lot of what I do in IDL involves using paths all over the place, the problem is, I want my code to work in Windows or Linux, but we of course have that old problem of / v \.
Generating a random number, or an array of random numbers, between 0 and 1, in IDL is easy. Simply call upon RANDOMU. But how do you generate random numbers between two other numbers?