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Show HN: Google Maps Shadow Calculator

120 points by gdaramouskas 5y ago

ldayley 5y ago
As an outdoor photographer I’m constantly referring to an ephemeris[0] to check out the light situation at different times. This isn’t nearly as full featured as what I use but I love the idea of hacking something like this together with common APIs for a quick and dirty approximation. Interesting work. Thank you. [0]: https://app.photoephemeris.com/ https://app.photoephemeris.com/
cyborgx7 5y ago
Very cool. Sorry for being "that guy" but I assume this doesn't take into account the earth surface curvature, just the relative sun position and then assumes a flat earth? It probably not nearly significant enough on the scale of the use case described on the site, but a shadow on a sphere has a different shape than a shadow on a plane. Though that effect may cancel out depending on the map projection that was used.
- mbustamanter 5y ago
  Assumes a flat surface, I've just tested it on a large crater [0]. [0] http://shadowcalculator.eu/#/lat/-23.928141910247348/lng/-68.26168716018941 http://shadowcalculator.eu/#/lat/-23.928141910247348/lng/-68...
- alfanick 5y ago
  Yup, seems to treat Earth as flat, not really useful in my area (living in the valley, surrounded by high mountains from east and west - sunrise time does not mean you're going to see sun, if it's still hiding behind a mountain).
weichbild 5y ago
Ah this is perfectly timed--many of the old garden-focused azimuth / altitude / persephone day calculators are defunct and never handled the problem of cast shadows very well in the first place. Nice work!
pmlamotte 5y ago
Very neat! An idea that often came up amongst coworkers while walking to a lunch spot during the hot summers was being able to get walking directions that preferred routes in shadow. We had our own routes we came up with that didn't add much time to the total trip but had a massive increase in shade versus almost none on the fastest route. This reminds me a lot of that, though you would need good data on building heights and shapes as well as which side of the sidewalk you would walk on (if walking on both is even possible). Would love to see that get created some day.
- tppiotrowski 5y ago
  One like this exists for Barcelona: https://www2.bcnregional.com/ https://www2.bcnregional.com/
mbustamanter 5y ago
Awesome work! I'm using it to figure out the shadows cast by the Twin Towers (417 m. and 415 m., North and South towers, respectively) at different times of the day and different dates. They were truly gargantuan buildings. http://shadowcalculator.eu/#/lat/40.71136008109719/lng/-74.0134699802004 http://shadowcalculator.eu/#/lat/40.71136008109719/lng/-74.0...
Snoozus 5y ago
so knowing the buliding height we could figure out which time and day the aerial picture was taken? And given time and day we could figure out how high the buildings are. Could this be used to generate large scale 3d building models automatically? Does anyone know whether this has been attempted?
- juki 5y ago
  > Could this be used to generate large scale 3d building models automatically? A lot of places have lidar data available that can be used for that.
compsciphd 5y ago
I actually proposed something similiar to friends at google maps, that it be interesting for walking directions to advise based on which route would be most shadowed (say in the hot summer in a non humid climate where there's a huge difference between shadowed and non shadowed paths in terms of comfort.
ricardo81 5y ago
Very nice. Confirms that installing solar panels on my roof simply isn't economical. Guess installers would find something like this handy.
a3_nm 5y ago
I thought this could solve the following problem: when camping during a mountain hike, figure out where to set up the tent, by knowing at which time you will be woken up by sunlight. Unfortunately this app doesn't seem to take elevation into account -- I don't know if there is some other tool that can do it.
- deleted 5y ago
  [deleted]
- deleted 5y ago
  [deleted]
- tppiotrowski 5y ago
  I made a tool for this. Check out https://shademap.app/@37.72457,-119.60944,10.69315z,1647011073272t,0b,0p https://shademap.app/@37.72457,-119.60944,10.69315z,16470110...
  - a3_nm 5y ago
    Nice, thanks!
  - folli 5y ago
    Big fan of your app (I even mention it in the thread, didn't see your comment): but what happened to the 3D view?
    - deleted 5y ago
      [deleted]
    - tppiotrowski 5y ago
      Too much traffic and a couple of Mapbox bills above $100 so I had to paywall it. Here’s more info: https://tedpiotrowski.svbtle.com/shade-map-pro https://tedpiotrowski.svbtle.com/shade-map-pro
victormier 5y ago
good job! would be great if you could add polygon params and datetimes in the url so it would be easier to share
dsmmcken 5y ago
The drag handles are a bit finicky/small to grab, and would be nice to be able to set the heights as a group. Otherwise great!
monkeydust 5y ago
Nice work. If your interested in using this for evaluating solar production then check out https://solcast.com/ https://solcast.com/ There is a free version. I have it hooked this up to Homeassistant and predicting output for my home solar rig.
- alias_neo 5y ago
  Could I use this to figure out what I might he able to achieve from adding solar to my home if I hooked it up to homeassistant? I'm in the UK and trying to work out if it's worth it with our subjectively poor sunlight.
seba_dos1 5y ago
The title is kinda misleading, as this has nothing to do with Google Maps other than using it as a map source.
pcthrowaway 5y ago
Wow, this is going to be great for determining ideal time of day to climb at different areas edit: the controls really could use some work though edit2: It doesn't appear to take elevation data into account, which might be useful. More to the point, it doesn't take shadows from surrounding terrain into account
folli 5y ago
I personally find http://shademap.app http://shademap.app much nicer. And obligatory plug for my Android App (if you need an Augmented Reality type of application to visualize the sun position): http://sunlocator.com http://sunlocator.com
- jihadjihad 5y ago
  I've got to say, as someone who lives nowhere near a city as big as NY, the view of the shadows that are cast upon Central Park throughout the day is simply mind blowing.

120 points by gdaramouskas 5y ago

As an outdoor photographer I’m constantly referring to an ephemeris[0] to check out the light situation at different times. This isn’t nearly as full featured as what I use but I love the idea of hacking something like this together with common APIs for a quick and dirty approximation. Interesting work. Thank you. [0]: https://app.photoephemeris.com/ https://app.photoephemeris.com/

cyborgx7 5y ago

Very cool. Sorry for being "that guy" but I assume this doesn't take into account the earth surface curvature, just the relative sun position and then assumes a flat earth? It probably not nearly significant enough on the scale of the use case described on the site, but a shadow on a sphere has a different shape than a shadow on a plane. Though that effect may cancel out depending on the map projection that was used.

mbustamanter 5y ago
Assumes a flat surface, I've just tested it on a large crater [0]. [0] http://shadowcalculator.eu/#/lat/-23.928141910247348/lng/-68.26168716018941 http://shadowcalculator.eu/#/lat/-23.928141910247348/lng/-68...
alfanick 5y ago
Yup, seems to treat Earth as flat, not really useful in my area (living in the valley, surrounded by high mountains from east and west - sunrise time does not mean you're going to see sun, if it's still hiding behind a mountain).

weichbild 5y ago

Ah this is perfectly timed--many of the old garden-focused azimuth / altitude / persephone day calculators are defunct and never handled the problem of cast shadows very well in the first place. Nice work!

pmlamotte 5y ago

Very neat! An idea that often came up amongst coworkers while walking to a lunch spot during the hot summers was being able to get walking directions that preferred routes in shadow. We had our own routes we came up with that didn't add much time to the total trip but had a massive increase in shade versus almost none on the fastest route. This reminds me a lot of that, though you would need good data on building heights and shapes as well as which side of the sidewalk you would walk on (if walking on both is even possible). Would love to see that get created some day.

tppiotrowski 5y ago
One like this exists for Barcelona: https://www2.bcnregional.com/ https://www2.bcnregional.com/

mbustamanter 5y ago

Awesome work! I'm using it to figure out the shadows cast by the Twin Towers (417 m. and 415 m., North and South towers, respectively) at different times of the day and different dates. They were truly gargantuan buildings. http://shadowcalculator.eu/#/lat/40.71136008109719/lng/-74.0134699802004 http://shadowcalculator.eu/#/lat/40.71136008109719/lng/-74.0...

Snoozus 5y ago

so knowing the buliding height we could figure out which time and day the aerial picture was taken? And given time and day we could figure out how high the buildings are. Could this be used to generate large scale 3d building models automatically? Does anyone know whether this has been attempted?

juki 5y ago
> Could this be used to generate large scale 3d building models automatically? A lot of places have lidar data available that can be used for that.

compsciphd 5y ago

I actually proposed something similiar to friends at google maps, that it be interesting for walking directions to advise based on which route would be most shadowed (say in the hot summer in a non humid climate where there's a huge difference between shadowed and non shadowed paths in terms of comfort.

ricardo81 5y ago

Very nice. Confirms that installing solar panels on my roof simply isn't economical. Guess installers would find something like this handy.

a3_nm 5y ago

I thought this could solve the following problem: when camping during a mountain hike, figure out where to set up the tent, by knowing at which time you will be woken up by sunlight. Unfortunately this app doesn't seem to take elevation into account -- I don't know if there is some other tool that can do it.

deleted 5y ago
[deleted]
deleted 5y ago
[deleted]
tppiotrowski 5y ago
I made a tool for this. Check out https://shademap.app/@37.72457,-119.60944,10.69315z,1647011073272t,0b,0p https://shademap.app/@37.72457,-119.60944,10.69315z,16470110...
- a3_nm 5y ago
  Nice, thanks!
- folli 5y ago
  Big fan of your app (I even mention it in the thread, didn't see your comment): but what happened to the 3D view?
  - deleted 5y ago
    [deleted]
  - tppiotrowski 5y ago
    Too much traffic and a couple of Mapbox bills above $100 so I had to paywall it. Here’s more info: https://tedpiotrowski.svbtle.com/shade-map-pro https://tedpiotrowski.svbtle.com/shade-map-pro

victormier 5y ago

good job! would be great if you could add polygon params and datetimes in the url so it would be easier to share

dsmmcken 5y ago

The drag handles are a bit finicky/small to grab, and would be nice to be able to set the heights as a group. Otherwise great!

monkeydust 5y ago

Nice work. If your interested in using this for evaluating solar production then check out https://solcast.com/ https://solcast.com/ There is a free version. I have it hooked this up to Homeassistant and predicting output for my home solar rig.

alias_neo 5y ago
Could I use this to figure out what I might he able to achieve from adding solar to my home if I hooked it up to homeassistant? I'm in the UK and trying to work out if it's worth it with our subjectively poor sunlight.

seba_dos1 5y ago

The title is kinda misleading, as this has nothing to do with Google Maps other than using it as a map source.

pcthrowaway 5y ago

Wow, this is going to be great for determining ideal time of day to climb at different areas edit: the controls really could use some work though edit2: It doesn't appear to take elevation data into account, which might be useful. More to the point, it doesn't take shadows from surrounding terrain into account

folli 5y ago

I personally find http://shademap.app http://shademap.app much nicer. And obligatory plug for my Android App (if you need an Augmented Reality type of application to visualize the sun position): http://sunlocator.com http://sunlocator.com

jihadjihad 5y ago
I've got to say, as someone who lives nowhere near a city as big as NY, the view of the shadows that are cast upon Central Park throughout the day is simply mind blowing.