Show HN: Every mountain, building and tree shadow mapped for any date and time

[tppiotrowski]

I've been working on this project for about 4 years. It began as terrain only because world wide elevation data was publicly available. I then added buildings from OpenStreetMap (crowd sourced) and more recently from Overture Maps data. Some computer vision/machine learning advancements [1] in the past few years have made it possible to estimate tree canopy heights using satellite imagery alone making it possible to finally add trees to the map. The data isn't perfect, but it's within +/- 3 meters of so. Good enough to give a general idea for any location on Earth. Happy to answer any questions.

[1] https://www.nature.com/articles/s41559-023-02206-6

[janpmz]

The Nazca lines in Peru seem to align with the shadows of the mountain, I made two videos to demonstrate it: https://x.com/janBuild/status/1796472554905022785

In the second video, you can see that the shadow seems to align with a curved line during summer solstice: https://x.com/janBuild/status/1796473232658518133

[xandrius]

You should definitely make the video more visual and add some helper lines. I watched the video 20+ times and still don't think they align (of course it's an approximation but still).

[causal]

Not sure I see it? Maybe would help to have someone highlight specific lines/shadows. I can maybe see it if I let my brain see some alignment and ignore the mostly not-aligned bits.

[Terr_]

Hmmm... I'm not an astronomer, and I wondered if they might have once been more-exact. It seems that while Earth's orbit has long term variations (eccentricity, obliquity, precession) the shortest of those cycles is still quite a lot longer than the estimated age of the Nazca lines. (Precession with a 26ky cycle, Nazca lines at 1.5 to 2.5ky.)

[thinkingemote]

Interesting! The area is at the tropics so there's not much shadows for the majority of the day. And it seems as if its only very early in the morning where these shadows occur. A small change in time and the shadow changes greatly. Equally a very small variation in elevation of the mountain and plain may give different results.

[lawlessone]

Interesting. Could they have used the shadows as for of ruler to keep things straight?

[blackhaj7]

Wow. Did you just crack the mystery?!

[blastro]

Wow! This is an awesome observation

[renewiltord]

Wow, is this a novel theory? That is the first time I’ve heard of it.

[DoctorOetker]

the shadow of the smaller and smaller peaks seems to also touch/trace thinner and thinner lines, these lines seem very different compared to the actual animal depictions in other Nazca lines. Could these lines be explained by diffrent rates of photosynthesis / occasional vegetation debsity variations selectively protecting the soil from erosion?

One nature demarcates curves, humans and animals will adapt to them in their choice of path.

[simonbarker87]

This site is great but it's only an approximation.

We've used this website for years for checking the sun in various potential homes and holiday rentals. It's a half decent approximation but it doesn't really have proper height data (I think it's using standard building classification from Open Street Map data?) so it's only a guide.

[Woeps]

Plus it seems to be missing a boat load of trees in the streets.

But it's pretty cool overall! And I'll keep it in mind as we're in the process of looking for a new home.

[jvanderbot]

What's the data source?

The premium map is really good for my neighborhood!

I wonder if it's image processing from Planet data or something. Shape from shadows (then back to shadows?)

[jodrellblank]

I’m surprised; I was thinking they might buy a few satellite photos through a sunny day and just… look at where the shadows are (with code).

Maybe working back from that could feedback how high the buildings might be.

[noduerme]

Funnily enough... it's completely missing the vacation rental mini chalet my neighbors built which casts shade over most of my backyard. I suppose this means it won't be missed on any surveys if it mysteriously gets knocked down.

[dolmen]

It definitely has no data about roof shapes.

[wesamco]

How the heck did it automatically pan the map to my current location, my small town, in an Incognito window, on page load?

Is IP geolocation this accurate and accessible to every website nowadays?

If this website can do this I assume every website I visit can do it too?

[LeifCarrotson]

Geo-IP through Cloudflare:

    <script id="cflocation"> 
        window.CFLocation = {"lat":####,"lng":####};window.CFDsm=null;
    </script>

See https://developers.cloudflare.com/network/ip-geolocation/.

Mine's off by more than 100 miles (Comcast Business fiber), it's not magic.

[ale42]

You should probably try what one of the few online demos of IP geolocation tell about your IP... (just to cite one among many, quality varies a lot across services and geographic zones: https://www.maxmind.com/en/locate-my-ip-address)

[davidmurdoch]

I thought the same. It's the first time I've ever seen IP geolocation get my home IP address correct. It usually thinks I'm in North Carolina (I'm in Florida).

[xp84]

It is very cheap and easy. Even the free versions of the database available from maxmind are plenty accurate for town level.

At my last job, I built a little docker image that used the free maxmind DB and kept it up to date, and ran a node server which returned some JSON telling estimated lat/long, city name, country, etc.

[antod]

Mine started in a different city about 520km away. And I wasn't incognito. Probably a lot more to do with your country, your ISP or coincidence than anything else.

[mcslambley]

I can't speak for this website specifically but Cloudflare makes it pretty easy to geolocate users based on request headers.

[moogleii]

A VPN should help with that. E.g. for the Mac folks, Private Relay on vs off was a delta of about 100 city blocks for me.

[BurningFrog]

FWIW it placed me 10 miles away.

Right city, completely wrong part. Maybe that's where my ISP has their connection?

[shepherdjerred]

That is crazy. Even Google Maps isn't this accurate for me with location turned off.

[c0nsumer]

First, I went and looked at my house... It's got a lot of tall oak trees near by and in a park across the street.

It shows it almost completely in daylight save for building shadows, which is really wrong even right now as most of the house is shaded by trees.

Then I see an upgrade button... and it wants me to pay. Yet I can't even validate the data passes a sniff test. Their free tier very much doesn't.

[ok_dad]

Yea the shadow data for my area is hilariously wrong. It’s missing a whole forest that shades my house and a road nearby.

[Jabrov]

I feel like the paid version is actually a bit better for trees

[oblib]

I'm impressed! I live on a forested ridge above a horseshoe bend in a big lake and there's a fairly steep hill behind our home. Our home is surrounded by big oak trees but there is a big front yard that's all lawn, and behind us there is a lot of open space where we have a pretty big garden and a pretty steep hill below that is forest with big hardwood trees. It pretty much nails down when and where it's shady.

[codingdave]

First off, this is cool and well done. I did notice an oddity, but the fact that we're all complaining about oddities and edge cases (pardon the pun) shows how well done it is. In any case, the wonky thing I noticed is that it effectively shows shadows on the edges of forests, but not on the forests themselves (at least in my area).

[n_plus_1_acc]

I had the same issue.

[kilian]

When it doesn't have height data it seems to set every building to the same height. Interesting, but it does make it inaccurate in my country.

[cr125rider]

OpenStreetMaps is pretty coarse with building heights. Seemingly just an integer with most buildings being 1 (stories?) from what I’ve seen.

[deckar01]

If anyone builds a version of this that accepts crowd sourced phone images to increase the accuracy with photogrammetry (before I get around to it) I will give you shademaps.com.

[temp3000]

Could also source this from images uploaded to Google etc?

[thih9]

Related mapbox-gl-shadow-simulator source code: https://github.com/ted-piotrowski/mapbox-gl-shadow-simulator

[mikkom]

I just had to check some really rural places and went to some random village in tibet. As there is no information about trees or buildings there, just roads, it surprisingly doesn't work - it just shows some shadows based on terrain heights in middle of empty village road grid.

So as expected, if the site has height information it can draw shadows but definitely not for "every building" etc that the title claims.

[brfox]

Manhattenhenge:

https://shademap.app/@40.75481,-73.98696,14.82042z,171702794...

https://www.amnh.org/research/hayden-planetarium/manhattanhe...

[rwmj]

One thing I often wonder is do car crashes happen more frequently when the sun is low in the sky and facing traffic? Surely someone has got together the data on traffic accidents, maps, times and a model of the earth/sun to work this out!

(Google search results for this are full of spam from a mix of motor insurance companies and sunglass companies)

[tazlor]

There is a section of I-70 in Colorado that experiences temporary closures due to severe sun glare at certain times of the day and year. https://www.codot.gov/travel/sunglare

[Aachen]

Couldn't tell you where I've read this but I heard years ago that it makes a difference indeed. Now I'm wondering if that was just the person who said or wrote it just giving an example of what kind of considerations you need to incorporate when optimising for safety, or if they actuality had data on this

[goqu]

This is so useful when buying a house in the country that sun is as valuable as gold and you want to maximise it in the backyard. Great tool.

[dang]

Related:

Using Lidar to map tree shadows - https://news.ycombinator.com/item?id=36658001 - July 2023 (41 comments)

Shade Map Pro - https://news.ycombinator.com/item?id=30532286 - March 2022 (12 comments)

Show HN: 3D map of shade around the world - https://news.ycombinator.com/item?id=29827943 - Jan 2022 (71 comments)

Map of shadows at any place and time - https://news.ycombinator.com/item?id=29681693 - Dec 2021 (4 comments)

Show HN: GPX replay map that shows terrain shadows during activities - https://news.ycombinator.com/item?id=28854959 - Oct 2021 (14 comments)

[davidmurdoch]

"Every" seems to be a bit of a stretch trees part. It's got maybe 5% of the tree shadows near me.

[Kim_Bruning]

https://www.youtube.com/watch?v=1HnOJirSCn8

Due to the initial location, an extra verse can now be added to this song. (About a little Café in Sneek that is somehow tenuously linked to pretty much everything)

[fscaramuzza]

As others have done, I first looked for my house. I noticed something I hadn't noticed ever, namely a spot in the neighborhood that is shaded for most of the day. A good trick to know when summer comes and you want to keep your car cool.

[carbocation]

Very cool. I looked at the Bay Bridge and it gets the towers but probably not the bridge itself (this is a trivial point except for folks right by the bridge, but fun to look for edge cases).

[jblindsay]

I love this, although I do wonder how accurate it is, given the likely limited underlying elevation data source. It reminds me a lot of an application for creating shadow animations based on digital elevation models that I wrote some time back https://www.whiteboxgeo.com/manual/wbw-user-manual/book/tool...

[thih9]

Here it is not showing any shadows in Honolulu mid-May around noon: https://shademap.app/@21.30371,-157.85237,16.56781z,17168489...

Which is how it should be[1]; cool!

[1]: https://en.wikipedia.org/wiki/Lahaina_Noon