<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">You were plotting individual segments for each and every time step, you inner do loop and use of gsn_polyline() wasn’t quite what you really wanted. Those dashes were actually new lines for each internal do loop. <div class=""><br class=""></div><div class=""><br class=""></div><div class="">I cleaned up the script and edited your do loop so it’s much simpler and uses gsn_add_polyline() instead. </div><div class=""><br class=""></div><div class="">Go through my edited file and make sure you understand what changed and why. I’d suggest running through one iteration of your days loop with a print(xpt) to realise why you were getting the plot you were getting. </div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">Alan</div><div class=""><br class=""></div><div class=""></div></body></html>