#1 background map calibration using sliders?

[Anonymous]

it would be handy if we could align the background map
using sliders for the scale and rotation, so that we
can directly see the effects of slider movement. Also,
it would be great if we could have a 3rd slider that
would allow spatial rotation/alignment of background
images that may have been shot at a certain angle.
Also, the scale of the background image could probably
be automatically determined if the user simply marks
the start and end of a known runway on the image, so
that taxidraw can simply calculate the length of the
line between the two pixels, ask the user which runway
was marked and then look up the corresponding runway's
length in order to determine the correct scale.