| Dear Ferreters, I've come across a question which is simple in theory but in practice I'm having a little trouble. So I'm wondering if anyone else has found a solution. What I would like to do is calculate the path length of an ocean current. To define the path of the current I pick a particular sea surface height contour, now I would like to be able to calculate the length of that contour. I've been trying to use @loc or @weq to select the points at which SSH reaches the value that I've chosen but they only find the first instance along a given latitude or longitude so they miss parts where the current meanders (and also sometimes pick up eddies). Is there a way to use @loc or @weq to find every instance of a particular value? Or has someone got a better solution? Thanks! Leela. ----------------------------------------------------------------------------------- Leela Frankcombe Post-doctoral researcher Institute for Marine and Atmospheric research Utrecht Utrecht University The Netherlands www.phys.uu.nl/~frankcmb l.m.frankcombe@xxxxx ----------------------------------------------------------------------------------- |