---
title: "Tulsa Shadow Walk | Sam Carlton"
source: "https://samcarlton.com/portfolio/tulsa-shadow-walk/"
---

# Tulsa Shadow Walk

June 2026

**A real-time MapLibre shade-walk app for downtown Tulsa.**

It computes building shadows from real OpenStreetMap footprints and NOAA-style solar position for any minute of any day, scores both sides of every downtown street block, finds shade windows, and routes shade-aware walks over the real OSM walking network. “Best time to walk” per block — including when both sides are shaded — is the differentiator for Tulsa heat.

## Links

-   **Site:** [Tulsa Shadow Walk (Fable)](https://shadow.samcarlton.com/fable/)
-   **Original prototype:** [Tulsa Shadow Walk (OBRA)](https://shadow.samcarlton.com/obra/)
-   **GitHub:** [fable-shadow-walk source](https://github.com/ThatGuySam/notes-search/tree/main/apps/fable-shadow-walk)
-   **GitHub:** [original OBRA prototype source](https://github.com/ThatGuySam/notes-search/tree/main/apps/addy-shadow-walk)

## Highlights

-   **Continuous-time shade** — a full-day time slider with date presets, instead of three hardcoded sun windows; sun altitude/azimuth shown live.
-   **Side-of-street scoring** — every block gets offset bands on both sides, sampled against the modeled shadows and colored sun-orange to shade-green.
-   **Shade-aware routing** — Dijkstra over the real OSM walking graph with Direct / Balanced / Vampire sun-aversion modes, plus sun-minutes and detour metrics.
-   **Free and static** — “Everything is free and static: Overpass-fetched OSM data, OpenFreeMap tiles, no keys, no backend storage.”
-   **Honest about limits** — “Side bands are synthetic offsets, not surveyed sidewalk geometry. Building shade only: no trees, awnings, terrain, or construction yet.”

## How It’s Built

-   **Frontend** — Vite and React, with an imperative MapLibre controller that owns the map and shade model outside the React render loop.
-   **Map engine** — MapLibre GL with OpenFreeMap tiles and OSM-derived roads and building polygons.
-   **Shade model** — NOAA-style sun position for any minute of any date; each building casts a hull-swept ground shadow from its height; point-in-shadow tests use a grid index rebuilt per time tick.
-   **Routing** — Dijkstra over OSM walkable ways with experienced-length costs that weight sun exposure.
-   **Mobile UI** — a Vaul drawer with rest, half-open, and full-open states.
-   **Hosting** — Cloudflare Worker plus static assets; all shade math runs client-side as browser ES modules, also imported directly by `node --test` suites.

## Screenshots

![Tulsa Shadow Walk desktop map showing downtown Tulsa shade scores and route metrics](/project-screenshots/tulsa-shadow-walk/tulsa-shadow-walk-desktop.png)

Desktop map workspace with route scoring, modeled building shadows, and side-of-street shade colors.

![Tulsa Shadow Walk mobile route planning sheet over the map](/project-screenshots/tulsa-shadow-walk/tulsa-shadow-walk-mobile.png)

Mobile map with the shade-aware route sheet and time controls.