I am used to drawing maps in QGIS and overlaying on top them a road network map showing the distance between places, its a useful way of showing information about roads.
But I am aware that its not showing everything, some classes of road allow much faster travel e.g. 10 minutes driving on a single track country road and I might cover two miles, were as on a motorway I might cover 10 miles.
Is there anyway I can use this information do distort either a shapefile or raster image of a generic to map to show the faster areas compared to the slower areas? I have a set of X/Y coordinates and the time to travel between them.
I am using QGIS to display my data. I normally keep my data in a PostGIS database.