I have successfully created an iso map for a small area of a road network and three points with forward and backward arc costs. However when trying to iterate over the three nodes to produce a separate iso for each, after the first completes I receive the error;
"local variable 'filename' referenced before assignment See log for more details"
And the process terminates. While I could select each point in this example, I am testing for a much bigger exercise. Could anyone point me in the direction of a solution?
Specs - QGIS 2.18.4 64bit, Windows 7 64bit. 2 .shp files stored on a network drive.