Add timezone grid caching to CLI (#17)

[borisnezlobin]

I've gone ahead and implemented the changes described in Galen's comment. The only notable change in behaviour is that now, by default, find_sun and find will attempt to read from timezone_grid.json (even if no --grid argument is passed). If this is unwanted, I can change it back, I just thought it would be a good default.

While testing, I found that finder.generate_timezone_grid() generates a JSON file that doesn't match the timezone_grid.json currently in this repo... is that intentional? Also, shadowfinder generate_timezone_grid will overwrite the file it's given — should that be changed?

[GalenReich]

finder.generate_timezone_grid() generates a JSON file that doesn't match the timezone_grid.json currently in this repo

This isn't intentional, and is probably not desired either! The behaviour is controlled by these defaults:

ShadowFinder/src/shadowfinder/shadowfinder.py

Lines 36 to 40 in e5f636b

	self.angular_resolution = 0.5
	self.min_lat = -60
	self.max_lat = 85
	self.min_lon = -180
	self.max_lon = 180

It would be good to understand why this is happening

[borisnezlobin]

I've just checked a lot more thoroughly (before, I was just looking at files changed, now I ran it through diffchecker.com) — the only difference is a trailing newline is removed. Sorry about that! I've also updated the tests so the reflect the new output.

[GalenReich]

In general it looks good!

One small thing, find_sun needs updating to include the grid argument.

[GalenReich]

I've just checked a lot more thoroughly (before, I was just looking at files changed, now I ran it through diffchecker.com) — the only difference is a trailing newline is removed. Sorry about that! I've also updated the tests so the reflect the new output.

No worries at all, better for it to be a newline than an entirely different set of points! So thank you for noticing the difference and double checking!

[borisnezlobin]

One small thing, find_sun needs updating to include the grid argument.

...oops. I've fixed it now, I think. Would it be a good idea to add the modified timezone_grid.json to Git (and, I think, disable the pre-commit formatting for it)?

[borisnezlobin]

bump. Anything else that needs to be fixed?

[GalenReich]

This all looks good - apologies about the delay, and thanks for the bump! 🙌