I am a newbie in PostGis and pgRouting. I have installed and configured both on my windows PC, following FOSS4G tutorial. I am able to see the result in browser, using GeoServer and OpenLayers. However, the starting and ending points are not the nearest edge of road, but the nearest node. I have created a 'Source', Target' and 'Edge' filed in my table. Using 'assign_vertex_id' function, source and target fields are getting populated. What to do with edge filed? Am I missing any step?