[QGIS-Developer] Sunrise, Sunset, Lunar Calculations

[Paolo Cavallini]

Hi Calvin,

On 28/06/19 01:18, Nyall Dawson wrote:
> On Fri, 28 Jun 2019 at 05:14, C Hamilton <adenaculture at gmail.com> wrote:
>>
>> How much interested would there be for a plugin to display sunrise and sunset information for a particular location on the earth's surface. Is anyone already working on this? There doesn't seem to be a capability for this, but perhaps I have missed it. Are there other astronomical calculations that would be worth while in QGIS? (Moon asimuth/position, phase)
>>
>> I a trying to get a sense of interest and also make sure I am not duplicating a capability someone is already working on.
> 
> This would be super-handy. I've needed this value in the past on
> different projects, and would love to see an easy way to calculate it
> in QGIS.
> 
> Can I suggest that the best form this would take would be a new
> expression function? E.g. sunrise(point_in_wgs_84, target_date) ->
> gives a time value in return. That would give maximum flexibility in
> terms of use (mmmm, i like the idea of dynamically styling event
> points using a different icon whether they occurred at night or day! I
> could imagine this being used heavily alongside Time Manager) .
> 
> I'd love to see it in core, if you want to contribute it as a c++
> function. I'm happy to mentor here, and writing new expression
> functions is a great, self-contained way to dive into the QGIS code
> base.

I agree, it can be useful. As a reference, also GRASS has since ages
similar calculations:
https://grass.osgeo.org/grass77/manuals/r.sun.html
and related commands.
Cheers.
-- 
Paolo Cavallini - www.faunalia.eu
QGIS.ORG Chair:
http://planet.qgis.org/planet/user/28/tag/qgis%20board/