<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="font-family: 'Lucida Grande'; "><div><span class="Apple-style-span" style="font-family: 'Lucida Grande'; ">Hello, everyone!</span></div><div><span class="Apple-style-span" style="font-family: 'Lucida Grande'; "><br></span></div><div><span class="Apple-style-span" style="font-family: 'Lucida Grande'; ">First time poster, here. I'm pretty new to JS, in general, and OpenLayers, particularly, but I'm really enjoying it so far. </span></div><div><span class="Apple-style-span" style="font-family: 'Lucida Grande'; "><br></span></div>I am curious if anyone has done something like what I am trying to do. My goal is to allow a user to select any two variables by means of a form. These variables could be, say, the number of people in Texas, by county, from 1991 to 1999. The goal is then</span><span class="Apple-style-span" style="font-family: 'Lucida Grande'; "> to create a new variable, Var3, where Var3 = (Var1 - Var2) and then style the entire map based on the value of Var3. (Each variable would obviously represent an attribute of the layer) I have got everything down except how to build a style based on the value of a derived variable. Any advice?</span><div><span class="Apple-style-span" style="font-family: 'Lucida Grande'; "><br></span></div><div><span class="Apple-style-span" style="font-family: 'Lucida Grande'; ">Thanks!</span></div><div><span class="Apple-style-span" style="font-family: 'Lucida Grande'; "><br></span></div><div><font class="Apple-style-span" face="'Lucida Grande'">Dheeraj</font></div></body></html>