I have a line layer and a point layer, I need the distance between the first and the last point measured along the line.
How can I do that using QGIS? Do I need to know linear reference? I don't have any knowledge on PostGIS.
You can use the new LRS plugin to QGIS 2.0: http://blazek.github.io/lrs/ . The plugin uses a tolerance (you can define) between the line and each point. I think this tool solve your problem.