Required processing:
Orthorectification and mosaicking of the satellite images, object-based image analysis (OBIA), vectorisation. The output of a dedicated line detector can be added into the object-based image analysis.
Data requirements:
Georeferenced lines delineating the main roads and broad tracks.
Why using remote sensors?:
Producing an up-to-date map of the roads for a region, a province etc. can help priority setting and mission planning.