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Show HN: Satellite imagery object detection using text prompts (useful-ai-tools.com)

53 points by eyasu6464 ↗ HN
I built a browser-based tool for detecting objects in satellite imagery using vision-language models (VLMs). You draw a polygon on the map and enter a text prompt such as "swimming pools", "oil tanks", or "buses". The system scans the selected area tile-by-tile and returns detections projected back onto the map as GeoJSON.

Pipeline: select area and zoom level, split the region into mercantile tiles, run each tile with the prompt through a VLM, convert predicted bounding boxes to geographic coordinates (WGS84), and render the results back on the map.

It works reasonably well for distinct structures in a zero-shot setting. occluded objects are still better handled by specialized detectors like YOLO models.

There is a public demo and no login required. I am mainly interested in feedback on detection quality, performance tradeoffs between VLMs and specialized detectors, and potential real-world use cases.

19 comments

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JimmyJamesJames
Great idea, almost impossible to use on the mobile due to the mobile UI.
ge96
Tangent question, I know of services like Planet Labs, Maxar... is the capability there now assuming you had money, where you could tag a ship from space and watch it travel (I know there is something like ADSB for ships) but would be interesting.
fusslo
very cool

Once I figured out how to use the UI I did 2 scans. first one I had to zoom in before the identification boxes popped up. At first I thought it didnt do anything

Second scan I put over a local aviation museum with a mix of helicopters, unusual planes, cars, buildings, and other equipment. I was surprised to see everything identified correctly, though it missed a single helicopter.

I'd love a little bell or notification when the scan completes, as I hit 'scan', switch to a different tab and then forgot I was waiting

eyasu6464
Thanks for trying it out. The detections not all appearing before zooming is because I added a LOD (level of detail) rendering method, so if hundreds of thousands of objects are detected, it won’t crash the system. Only the areas you’re looking at render, and the more you zoom in, the more objects are displayed. It was a pain to set up, but it’s worth it. The notification idea is great, and I’ll add a sound to play when a scan finishes.
whall6
I have been looking for a way to find pickleball courts near my house. This sounded like the perfect tool! I tried "pickle ball court" using the maximum polygon size (actually just slightly under) and... it didn't work. It gave me a red dashed square around a driveway to what looked like a farm.

Cool concept though.

iFred
What kind of image set is used here? A quick scan over the site and I don't know if I can provided my own aerial or satellite imagery or if you provide it.
sixothree
It successfully located a submerged car in a bayou. (Note, this is a known finding, and nothing reportable). So I think there are some possible positive use cases here. I'm curious what other unsolved mysteries are now solvable with computation.
thenthenthen
Very cool, been trying to make something like this as well (for very niche usecases). If i am on mobile the selection polygon max size seems to be very small, like the size of one block?
eyasu6464
I’m thinking about adding new features. Which one is more useful and should come next: searching with an image of an object, detecting changes over time using Sentinel-2 data, or detecting object in all Google Street View images within a selected area?
notahacker
Depends what you're going for. Change detection has a lot of established use cases but not sure whether LLM interfaces will add usability or remove accuracy; object detection in Google Street View images sounds cool and novel, but not sure what the actual use case is...
thenthenthen
Searching with an image of an object 100%!! (Or just like, find similar areas from a sat crop/screenshot!
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toader
How should the search box respond to a search of Las Vegas, NV or San Antonio, TX? I'm not getting any response.
notahacker
Interesting to see this change between uses (the bounding boxes are better than the heatmaps I saw the first time I tried it!)

The AI struggles a bit with less generic terms. It correctly realised Radcliffe Camera was a building, but tagged another building as well and guessed wrong for Balliol Library (I guess the models haven't seen it from above). On the other hand I was pleased it tagged narrowboats and didn't tag them as fish when I asked it to find fish on that tile...