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

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 · 2 years ago

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 · 2 years ago

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.

lm28469 · 2 years ago

That's what I see:

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

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

Terr_ · 2 years ago

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 · 2 years ago

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 · 2 years ago

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

blackhaj7 · 2 years ago

Wow. Did you just crack the mystery?!

blastro · 2 years ago

Wow! This is an awesome observation

renewiltord · 2 years ago

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

DoctorOetker · 2 years ago

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.

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 · 2 years ago

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.

tills13 · 2 years ago

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

aeyes · 2 years ago

Cloudflare only gives you the country

ale42 · 2 years ago

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)

nozzlegear · 2 years ago

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).

Retric · 2 years ago

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.

pavon · 2 years ago

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.

davidmurdoch · 2 years ago

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).

hoosieree · 2 years ago

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

xp84 · 2 years ago

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.

regularfry · 2 years ago

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.

Deleted Comment

antod · 2 years ago

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 · 2 years ago

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

moogleii · 2 years ago

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 · 2 years ago

FWIW it placed me 10 miles away.

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

shepherdjerred · 2 years ago

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

janpmz · 2 years ago

simonbarker87 · 2 years ago

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 · 2 years ago

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 · 2 years ago

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.

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 · 2 years ago

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.

martyvis · 2 years ago

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)

noduerme · 2 years ago

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 · 2 years ago

It definitely has no data about roof shapes.

wesamco · 2 years ago

c0nsumer · 2 years ago

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 · 2 years ago

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

tppiotrowski · 2 years ago

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.

Jabrov · 2 years 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?

oblib · 2 years ago

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 · 2 years ago

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 · 2 years ago

I had the same issue.

kilian · 2 years ago

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 · 2 years ago

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

Aachen · 2 years ago

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.

deckar01 · 2 years ago

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 · 2 years ago

Could also source this from images uploaded to Google etc?