[HN Gopher] Show HN: Satellite imagery object detection using te...
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       Show HN: Satellite imagery object detection using text prompts
        
       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.
        
       Author : eyasu6464
       Score  : 31 points
       Date   : 2026-03-09 07:52 UTC (2 days ago)
        
 (HTM) web link (www.useful-ai-tools.com)
 (TXT) w3m dump (www.useful-ai-tools.com)
        
       | triplecheese wrote:
       | This is cool. I'll give it a go
        
       | JimmyJamesJames wrote:
       | Great idea, almost impossible to use on the mobile due to the
       | mobile UI.
        
         | eyasu6464 wrote:
         | Thanks for the feedback. I've resolved the UI issues on mobile.
        
       | ge96 wrote:
       | 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.
        
         | notahacker wrote:
         | It's still at the "technical challenge to fuse data from AIS
         | [ADSB for ships, complete with spoofing and transponders being
         | turned off] to [generally] static images from multiple
         | different sources" stage, at least unless you've got the budget
         | for a video satellite to stick in a geostationary-ish orbit
        
           | ge96 wrote:
           | I also wasn't sure how good satellite image quality is where
           | you can match a ship from above, maybe the pattern of the
           | freight containers could help.
           | 
           | And track I didn't indicate frequency, it's not per minute,
           | but say hourly.
        
         | sorenjan wrote:
         | Planet labs has a solution specifically for ships.
         | 
         | https://www.planet.com/pulse/illuminate-the-dark-fleet-with-...
        
       | fusslo wrote:
       | 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 wrote:
         | 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.
        
           | fusslo wrote:
           | Thanks, makes sense to me. I was just confused at first since
           | i thought maybe it didnt do anything or my adblocker was
           | making it go weird
        
       | whall6 wrote:
       | 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.
        
         | eyasu6464 wrote:
         | Thanks for the feedback. A dashed square marks the area you
         | select for detection, and once it's finished, the results will
         | appear. You might want to give it another try because I just
         | tested it on the pickleball courts at 1108 S Harvey Ave,
         | Oklahoma City, OK, 73109, ( https://www.useful-ai-
         | tools.com/tools/satellite-analysis-dem... ) on Ultra High and
         | it detected all of them.
        
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       (page generated 2026-03-11 23:01 UTC)