feat: add angle subdivision cli option

[ryan-berger]

We currently only calculate 360 different lines of sight with our azimuthal projection. This can potentially lead to a lack of coverage, especially in very long lines of sight. This adds a command line option --angle-subdivisions which allows for a user-configured angle subdivision to get coverage up to .01 of a degree

[tombh]

Another thing I thought, is there a simple smoke test for this? Like how much do the TVS and Longest Line unit tests change with more angles? And did you try making a heatmap PNG?

We also need to update the viewshed code to be able to create viewsheds from increased angles. We can just make an issue for that.

[tombh]

Just thought of something else: we're losing fidelity because the angle is stored as i16. So we could either bump up the type, or I wonder if we store some metadata somewhere that defines the subdivision count? 32,767 is sooo nearly 360*100!

[ryan-berger]

Before this ever gets merged we need #42 to be finalized and then we can decide how to add this on top of it.

I agree that even a u16 would be better. I'm not sure if we want to use an f16 as we've discussed offline as it isn't clear that we can represent the fractional values we need. Plus the platform support isn't amazing.

I think the best option is to keep it as a u16 and then add something to our format which lets you know the highest potential value (say 720) so that you can know what incrementing a single value is a fraction of (.5 in the case of 720)