I understand how to create a custom horizon in SkySafari 5 Pro, using a panorama image (btw, it would be nice if the help page for that was updated to clarify the instructions about the resolution to use, since it now says 4096 x 2048 in one place and 2048 x 1024 in another). But when setting up somewhere new, it can take quite a while to go through the process of stitching together a panorama, processing via photoshop, and exporting to get a horizon that can be used for planning observations (or quickly evaluating whether to use a given location or move to somewhere else). For that, a crude approximation of the horizon that can be quickly created would be helpful. It's also harder to generate a panorama once it's dark.
I'm imagining the transparent line and translucent area modes having an "edit" option that allows handle points to be added. These could then be dragged close to stars that are just rising or setting above obstructions. The horizon line would have a straight connection between the handle points. For example, if I have a building on the horizon, I might create four handles, two to anchor the base of the building and two to indicate the roofline. For a tree, I might start with three points, drag one up to the top of the tree, then add more along the sides of the resulting triangle and drag them out to approximate its shape. If I can then name and save that, move to a new location, and repeat the process, I could step through time, switching between them, and have a sense of whether one place is better in terms of rising objects of interest clearing obstructions earlier. For something like this, I don't need a precise or detailed horizon, or even a complete 360 degrees.
