Elie Hasbani

Work / Blue Plaque Hunter

Blue Plaque Hunter

Partial 2026

A heritage game for the street: find a blue plaque on the map, photograph it, and collect it once the inscription and your location check out.

Recorded from the running web version and its OCR server: find, photograph, read, match, collect. The location is simulated at the plaque, the plaque photo is generated, and the OCR wait is shortened.

What it does

The map holds 2,264 plaques merged from public heritage sources, plus guided walks and daily quests. You pick a plaque, stand in front of it and take a photo. OCR reads the inscription, and collection only unlocks when the text matches that plaque and you are close enough to it. The server validates the claim and awards points. New plaques can be submitted, and they wait for moderation.

How it runs

  1. Open the map of plaques, walks and daily quests
  2. Pick a plaque and walk to it
  3. Stand in front of it and take a photo
  4. OCR reads the inscription and your distance is checked
  5. The server validates the claim and awards points
  6. Your collection and quests update

How it works

Plaque data is imported from Wikipedia lists, heritage ArcGIS layers and OpenStreetMap, then de-duplicated and audited, and every record keeps its source, licence and coordinate confidence. There are 18 curated walks, each with a distance, a duration and points. The OCR server runs Tesseract with image preprocessing behind bearer tokens, rate limits, upload limits and Helmet. The mobile app is built with Expo and React Native, using a native map, the camera and foreground location; a web version shares the same game rules.

Skills shown

Data engineering
Imports and de-duplicates plaques from Wikipedia, ArcGIS and OpenStreetMap, keeping each record’s source and licence.
Security
The OCR server sits behind bearer tokens, rate limits, upload limits and Helmet.
APIs & backend
An Express server validates each claim and awards points.
AI, agents & ML
Tesseract OCR with image preprocessing reads the plaque’s inscription from a photo.
Mobile apps
An Expo and React Native app with a native map, the camera and foreground location.

Worth knowing

  • Imports and de-duplicates plaques from several public sources into one database, keeping each record's provenance and licence.
  • Collection is gated twice: the OCR text must match the plaque, and the device must be close enough to it.
  • The OCR server preprocesses photos and runs Tesseract behind tokens, rate limits and upload limits.
  • Guided walks string plaques into routes with distance, time and points.