Satellite Imagery of Every Outdoor Basketball Court in the USA | Hacker News Reader

Satellite Imagery of Every Outdoor Basketball Court in the USA

pudding.cool

84 pointsBrajeshwar42 comments

I zoomed into a handful of random spots, and quite a few (maybe 30%) do not appear to show basketball courts at all. Many seem to be just rooftops or construction sites.

I wonder if it's including indoor courts?

Unlikely, I zoomed in on one that had a pool with round edges within a square concrete area that had the rough geometry of a basketball court and I imagine a image recognition engine being confused by that.

One that I saw was a baseball field

I saw one that showed a soccer field and looked on openstreetmap and saw it has a basketball court labeled there.

The labels seem to be taken from OpenStreetMap, so blame imperfect labelling there.

I guess taking labels from OSM is akin to taking your facts from Wikipedia (except that Wikipedia actually tends to be pretty well curated these days).

In fairness to OSM volunteers, a lot of Wikipedia's subject space is historical or otherwise relatively stable, while everywhere OSM maps is in danger of being changed in the real world. Just comprehensively mapping one small town takes many hours and by the time you work your way through region much of what you mapped will be different IRL. Aerial photography only updates periodically, which helps in a sense but also hurts because anything you map with that will most likely be outdated from the start.

"Bethpage, NY" is not a basketball court...

Also saw a bunch of tennis courts

Don’t your neighbors dunk off their roof?

Weird... I zoomed into hundreds, and saw 2 or 3 that weren't accurate. YMMV i guess

Just to quibble slightly, it does not seem to include US territories such as Guam [0] and American Samoa [1], but still quite impressive!

0: https://maps.app.goo.gl/xvC9s6dVo264JFaKA?g_st=ic

1: https://maps.app.goo.gl/4aTmEyxG1Fa2GFRKA?g_st=ic

See Joey Lee's Atlas of LA Pools for significantly cooler prior art.

https://jk-lee.com/projects/the-big-atlas-of-la-pools/

there's ~0% chance there's only 50K outdoor basketball courts in the US. Other comments observe a ~30% false positive rate. So this is probably "a yeoman's ML pass at a lot of map tiles I scraped" more than "satellite imagery of every outdoor basketball court"

It is using courts labelled in OpenStreetMap

You only need to look briefly to ascertain that the false positive rate is no where near 30%.

Doing some research on schools, parks, churches, etc. where courts commonly are implies the number of courts here may be way too low. I assume this was a model trained by manually curated examples, so I wonder if a class of examples was missing from the training data.

I randomly thought of one in my city and went to look for it. It was missing, at 28.5860615, -81.3010721 or at least the court doesn't come up if you type the ZIP code there into the search box.

Those are some ICBM-level precisions bro. How many centimeters wide is your court?

The satellite image of this place on Google Maps is extremely obscured by the tree shadows, which may have deceived the recognition.

The labels come from OSM so it was probably done by somebody manually looking over Bing's aerial photography and manually tracing what they can see. The iD editor uses Bing not Google.

It is not a model, it is "just" using openstreetmap labels.

Are these public courts only? Are residential courts included? I have a tough time believing there are only 59k outdoor courts in the US.

they probably aren't counting hoops over unlined pavement

I can't find any of my neighbors' courts in here, but I do see one or two backyard courts in my city.

Are there any technical details available on how these images were captured. I'm assuming some form of Vision AI (YOLO?) was leveraged. What source data was used, and how was it processed?

I'm interested in doing something similar for tennis courts.

(just a guess. I can't load it on mobile)

This could be done with OpenStreetMap metadata.

EDIT: I was right. In the "About" dialog:

> Court Locations via Open Street Map. Satellite imagery via Google.

The other comments are a let down so far. I find this impressive!

Seems to only include public outdoor courts. The many private courts, at least the handful i know about, must not have been in the database.

The browser tab choked at 42k. Windows 11/Firefox

It seems that no one is playing basketball these days... It looks like that only one out of 10 has players.

Prime satellite photo time is probably not the time of day most people get to play basketball recreationally.

The page reliably crashes my Firefox

Is there a reason I can't find any courts in Oklahoma?

there is no reason. i'm looking at some right now

I can find courts in Oklahoma by entering "Oklahoma" in the search box and selecting Oklahoma from the dropdown menu. Are you not getting the dropdown? It sometimes takes a few seconds for it to appear after you enter your search term.

I'm from Midwest City and searched that and found the court at Regional Park. But I searched for Midwest City and not Oklahoma

Why?

I guess as an example of using AI image processing on satellite imagery. E.g. instead of basketball courts you could let it automatically find military targets...

No, it's from OpenStreetMap manual labelling by contributors.

Ok then it's mostly nonsense... Maybe some practice project?

What the heck is that in Jackson, TN??

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