Show HN: Every mountain, building and tree shadow mapped for any date and time | Hacker News Reader

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

shademap.app

685 pointstppiotrowski183 comments

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

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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

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).

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.

That's what I see:

https://i.imgur.com/s1uihNT.jpeg

https://i.imgur.com/dVrC8eC.jpeg

Hmm yeah these particular shadows don't look that well aligned to me, but the hypothesis certainly warrants more searching

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.)

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.

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

Wow. Did you just crack the mystery?!

Wow! This is an awesome observation

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

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.

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.

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.

Did you try the paid data? The free one missed most the trees, but the $2 map showed all the trees in my nearby park. Really impressive.

So - how do I know if the paid version is accurate if the free version is inaccurate? It shows me a sample of some place I don't know so it's impossible to evaluate.

They should offer some other way to trial the full version.

$2 is how.

The sample convinced me. $2 is a really small investment.

Nice! Last time I found something like this was a 15$/mo yearly subscription, which was clearly targeted at real state agents, and didn't make any sense for a one time check... Luckily they just believed the system clock, so at least I could check over the year by changing the computer time

Edit: looks like they already show side-by-side samples, https://news.ycombinator.com/item?id=40535186.

They could probably have a side-by-side comparison of somewhere famous like Central Park (I'm from UK, fwiw) showing the free vs paid data to give an idea of what one might get; I guess it varies by location how much detail is mapped though, and how recently.

The ‘try a sample’ link in the upgrade flow drops you into Central Park West with the full data.

A few months ago I paired for the tree data to figure out the best place on our property to place some planter beds.

I’m very happy with the results. It confirmed my guess that a specific section gets more light over the year even though there is a bit more shade in the mornings until late spring.

Can you share screenshots of both side by side? (perhaps of some area not your backyard if you don't want to reveal where that is?)

If you click on the premium version, it will show a sample of a chosen area to show you how much more detail (esp re: trees) will be available. Even that was kinda worse than what I got.

For me it only increases the resolution, but not the correctness. The shadows have more detail, but are still wrong.

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?)

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.

They seem to have proper shadow information. I live in a semi-rural village and shadows from trees along our street are quite accurate ( and seem to be based on one section before it was cleared a year ago or so)

The trees thing seems to be new, I’m not sure I’ve noticed that before

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.

It definitely has no data about roof shapes.

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?

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.

It's probably either just the lat long of the PoP or some magic based connection latency?

Cloudflare only gives you the country

No. https://developers.cloudflare.com/rules/transform/managed-tr...

Then how did the website end up just about a mile from my house?

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)

This makes me glad I have iCloud Private Relay turned on for all of my devices and my wife’s devices. Clicking on this link showed my location as Birmingham, Alabama, more than 1000 miles away from my actual location in northern Iowa. Several of the other IP geolocation sites others have linked in this thread showed places like Chicago (closer), and Dallas (much further).

Well, the jokes on you: Now we all know that you're in northern Iowa.

obviously, that's yet another layer of misdirection. They're probably in Nebraska, laughing at all of us.

That’s narrowing things down to a 200km radius for me and while I am within that circle it’s center is over 100km from me.

Interesting. I have a static IP, and have kept that same IP through multiple moves around the state, but it knows my current zip code. I wonder if that is because my ISP shares the zip code, or through association with data collected from other sites.

And yet every site that uses IP geolocation for useful purposes thinks I'm in a completely different state that bounces around every few months, if I don't let the browser share my location.

I work for IPinfo.io (feel free to check your location data with us to see if we are correct as well). It is most likely that your ISP is sharing your zip code via a WHOIS/geofeed record.

For me, Firefox and without iCloud Private Relay engaged, Maxmind is within about 2km and doesn't get the city correct (but we're right on a border), and IPinfo is about 15km as the crow flies (and gets the city entirely wrong).

That is very unfortunate. If you reach out to support and drop a correction with us, that will be quite helpful.

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).

Same here. But knowing my ISP, it'll change throughout the day, sometimes by quite a lot.

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.

Cheap, easy, and wrong. It puts me a clear 800km away from where I'm actually sitting, and I'm sitting in a major UK city.

It's put me on the wrong continent before now. That was fun.

Cheap, easy, and generally correct for the majority of people*

Just because it’s 800km off for your IP does not mean it’s 800km off for every IP and Maxmind is generally considered one of the reliable providers of this information.

I guess the accuracy really depends on your location or ISP.

I believe my ISP rarely or never rotates IP addresses, and on top of that I think my ISP provided router is assigned an IPv6 address and it prioritizes using it, because when I visit whatismyipaddress.com with JS disabled, it can only show my IPv6 address, but if I enable JS it can show an IPv4 address too (I assume through the WebRTC IP leak method, which requires JS)

When I built the thing I mentioned, and even if i did so now, I'd just not make an AAAA record for it, because it's still safe to assume ipv4 connectivity exists (and not just via some remote proxy or something), and I think at least the database I had access to was for ipv4.

I don't think they need any hackery to get your IPv4, they just need a separate hostname configured that they can fetch from, which only has an ipv4 (A) record.

Where do we locate you? https://ipinfo.io/

If the location data is incorrect, you can always submit a correction with us: https://ipinfo.io/corrections

Mine was about 600 km wrong but the correct country at least. It's reporting the ISP's location but it's a country wide ISP.

If you reach out to support and drop a correction with us, that will be quite helpful. This is an unusually high deviation, so we would like to investigate it.

Better! Still 200km out, but better!

200 KM means there is room for improvement. If you reach out to support and provide a correction, that will be quite helpful. If you mention that you came from HN, I can report back on why we had such a deviation.

> It's put me on the wrong continent before now

What did you expect after leaving Europe? /s

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.

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

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.

FWIW it placed me 10 miles away.

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

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

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.

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

By default the tree shadows appear as they would from an airplane, so you would not see any shadows at noon as the top of the canopy is completely in the sun.

Try changing to "below canopy" in the Settings and you might see the missing shadows.

Mine still has a forest next door that was cut down 8-9 yrs ago.

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

It may be, but without a way to see that, why would I ever consider paying?

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.

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).

I had the same issue.

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.

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

I don't have this data at hand, and often it's hard to see from out front or differs for different parts of the building. So while an avid OpenStreetMap contributor, I rarely add height info to buildings

Perhaps I should look into high resolution height data (that is, high enough that an individual building shows up at all) with licenses that allow use in OSM and at least tag the buildings that show having a mostly uniform height. For example in the Netherlands, AHN is amazing (hundreds of points per tree! It looks like a 3d wireframe render of the entire country, truly amazing) but the license is not permissive enough.

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.

Could also source this from images uploaded to Google etc?

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

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.

well... of course?

I personally thought the interesting part of the submission was the "every" of the title, ie there might have been some AI algo that could have somehow approximated height and shadows based on multiple satellite images or use some data that is not available for everyone (hence the "every" could have applied)

Currently it's an approximation of shadows based on unreliable open data which is nice but not that special.

They shouldn't be using "every". It sounds like the kind of thing American programmers say.

Some people still thinks words should mean what they mean.

The irony that I've written a typo in a comment about words is not lost on me.

Manhattenhenge:

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

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

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)

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

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

I was on a bike stopped at a stoplight and was rear-ended by a car for this very reason.

As a young driver I was given the advice that if you see a lot of oncoming cars using their sunshade or squinting into the sun as they come towards you, it's time to pull over and wait it out.

Driving with the sun at your back is never a good time to be on the road.

Crossing the road as a pedestrian neither.

Yes

Perplexity thinks yes. https://www.perplexity.ai/page/Do-Car-Crashes-kmZIsMnbR4qcdx...

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.

You especially want to maximise the sun to light your solar panels.

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)

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

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)

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.

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).

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...

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

I don't know how the mechanics of it would work, but some kind of local accuracy index would be very useful in such broad maps.

Because the elephant in the room with most global dataset compilations is that the accuracy varies greatly from place to place. Some countries or regions have detailed data, others have generic or unclassified blobs. Some data is older, some is newer.

An ideal tool reduces the need for detailed provenance checking upon every usage.

Wow, I had such an idea years ago when walking under blazing sun following gps directions, I wished that it would plan the route according to shade.

A Chinese map (https://www.amap.com/) has it, but only for some cities in China.

I've thought of and yearned for this too. Conversely, in the winter I'd like a path with maximum sun exposure.

    There's a dark and a troubled side of life;
    There's a bright and a sunny side, too;
    Tho' we meet with the darkness and strife,
    The sunny side we also may view.

    Keep on the sunny side, always on the sunny side,
    Keep on the sunny side of life;
    It will help us every day, it will brighten all the way,
    If we keep on the sunny side of life.