Align tab, how is it used?

[pviolette92]

I will be uploading lots of railroad maps in rural areas that wont have intersections that would allow easy rectification.

They all have match lines, so they would be very easy to align to each other, but hard to align to aerial photography.

Is the align tab supposed to allow you to align a newly uploaded map to a rectified one? That would make it very easy to upload a map in urban areas, then upload the rural map and rectify the match lines together. I just need the ability to rectify to an uploaded map vs the aerial/openstreets map.

[DonpK]

I'd also be interested in more details on using the Align feature.