qgis - Controlling line width when merging vector files into raster?

Using QGIS on Windows 7, I have figured out how to burn a vector file onto a QGIS georeferenced tiff. But the result produces a line only one pixel wide. I am trying to produce a map that can be used both as printed and on a mobile device to guide hikers and the narrow line isn't sufficiently visible.

Is there a way to make the line wider or otherwise more visible?

I am a non-programer and completely new to QGIS.

Answer

Buffer the lines. You can make them as thick as you want that way. Then rasterize the resulting polygon layer.