Redlined: The Shape of Inequality

An interactive 3D visualization of HOLC redlining maps revealing how 1930s policy decisions shaped American cities, building by building.

Overview

Redlined transforms the Home Owners' Loan Corporation's 1938 neighborhood grading data into an immersive 3D experience. Users can explore Milwaukee's 114 HOLC zones as extruded geometry on a Mapbox GL map, read the original racist appraiser descriptions, ask an AI guide questions about what they're seeing, and toggle data overlays to see how 1930s policy maps onto present-day inequality.

The project starts with Milwaukee, Wisconsin — one of the most segregated cities in America — where the connection between 1938 HOLC grades and today's outcomes is stark and well-documented.

Created by Tarik Moody | Radio Milwaukee / The Intersection | Black History Month 2026

Features

• The Archive — Museum-quality interactive gallery (Motion.dev spring animations) with three sections:

  • The Original Map — Pinch/zoom/drag viewer for the 1938 HOLC security map scan (43MB → optimized 2K/4K progressive JPEGs)
  • Through the Lens — 20 curated 1936 Library of Congress FSA photographs by Carl Mydans, with category filters, staggered spring entrance, lightbox with keyboard navigation
  • The Timeline — 12 events across 5 eras (1933–2020) tracing the arc from HOLC's creation to Milwaukee's present-day segregation

• 3D HOLC Zone Explorer — 114 Milwaukee zones as Mapbox GL fill layers with 45-degree pitch, color-coded with the original HOLC palette (A=green, B=blue, C=yellow, D=red)

• 148K Building Extrusions — Individual buildings rendered from PMTiles vector tiles at zoom 11+, with click-to-inspect showing street address, TAXKEY, year built, assessed value, stories, and HOLC zone context

• Click-to-Inspect — Select any zone to read the original 1938 appraiser language, including explicitly racist descriptions, with content warnings

• AI Narrative Guide ("Ask the Guide") — Ask Claude questions grounded in actual HOLC data and appraiser text, with zone-aware suggested questions, contextual placeholder text, rate limiting (5/min, 30/hour, 100/day per session), topic guardrails, and bot protection

• Narrative Zone Detail Panel — Three-act story structure connecting 1938 decisions to present-day outcomes:

  • Act 1 — "The 1938 Decision": Dynamic sentence citing the appraiser's specific reasoning (racial composition, "infiltration," detrimental influences), inline Historic Redlining Score badge, and the original appraisal behind a contextual content warning
  • Act 2 — "What Happened Next": Collapsible decades-of-change section written for museum visitors — plain-English narratives ("Who Owned Their Home?", "How Much Did Families Earn?"), amber insight callouts, progressive-disclosure income table, full year labels, and zone-specific neighborhood narrative
  • Act 3 — "What It Means Today": Plain-language headline above the active data overlay (e.g., "Families here earn 2.7x less than in best-rated neighborhoods") with a prompt to toggle overlays when none is active

• Historic Redlining Scores (HRS) — Continuous 1.0–4.0 severity score per zone from Lynch et al.'s openICPSR dataset, showing how redlining intensity correlates with present-day outcomes (D-zone avg: 3.70, A-zone avg: 1.74)

• Data Overlays — Five toggleable overlays reveal 87 years of consequences:

  • Median Income — Census ACS household income by HOLC zone
  • Health Outcomes — CDC PLACES health risk index
  • Environmental Burden — EPA EJScreen environmental justice data
  • Assessed Value — Milwaukee MPROP property assessments with 1938-vs-today comparison
  • Race & Demographics — Census race data alongside 1938 HOLC racial assessments, revealing persistent segregation

• Racial Covenants Layer — 32,219 geocoded racial covenants from Milwaukee County property deeds (1910-1959), sourced from UWM's Mapping Racism & Resistance project. Heatmap at low zoom, individual amber dots at high zoom. Timeline-linked: scrub the time slider to watch covenants accumulate year by year (71% filed in the 1920s alone). Click any dot to read the original deed language with content warning.

• Ghost Buildings — 15,738 demolished structures (2005-2020) visualized as grade-colored circles, sized by demolition count per zone, with close button on the floating legend

• Sanborn Map Context — Fire insurance atlas overlay connecting 1938 building conditions to modern-day demolition patterns

• Decades of Change — Grade-level income and home ownership trends across 5 decades (1950-2020), combining published research statistics with Census API data, presented as plain-English narratives for general audiences

• Guided Story Mode ("The Lines They Drew") — 6-beat cinematic narrative that auto-launches on first visit, flying the camera across Milwaukee while activating zones, overlays, covenants, and ghost buildings at each beat. Available via red "Guided Tour" header button for return visitors. Each beat includes expandable "Learn more" sections with academic citations that open full PDFs in the built-in viewer. Keyboard (Left/Right/Escape/Enter), swipe, and dot navigation. Code-split with Motion.dev transitions.

  • Beat 1: "The Grading" — City overview, 1938, 114 zones explained
  • Beat 2: "Best in Class" — Zone A1 (Shorewood/Whitefish Bay), the wealth engine
  • Beat 3: "Hazardous" — Zone D5 (Bronzeville Core), Walnut Street's vibrant history
  • Beat 4: "What Was Lost" — Zone D6 (Triangle), 2,116 demolished buildings, I-43 destruction
  • Beat 5: "The Invisible Lines" — 32,219 racial covenants, year 1926
  • Beat 6: "Still Here" — Income overlay, 2.7x gap, Harambee resilience

• Bronzeville Scrollytelling Deep Dive — Dedicated /bronzeville route with scroll-driven map storytelling (NYT "Snow Fall" style). 8 chapters trace the arc of Milwaukee's Bronzeville neighborhood:

  1. "The Arrival" — Great Migration, 21,000 African Americans settle by 1940
  2. "Walnut Street" — The vibrant Black Main Street with jazz clubs and businesses
  3. "Stamped Hazardous" — HOLC arrives, D-grade cuts off mortgage lending
  4. "The Invisible Wall" — 32,219 racial covenants walling in the community
  5. "The Bulldozers" — I-43 highway destroys Walnut Street, 3,371 units lost
  6. "The Sound of Absence" — Jazz clubs silenced, employment collapses
  7. "What Remains" — 7,349 D-zone demolitions vs 39 in A-zones, ghost buildings
  8. "Still Here" — Harambee community rebuilding, 2.7x income gap persists

  Desktop: sticky map (60%) + scrolling narrative (40%). Mobile: fixed map behind with backdrop-blur cards. Motion.dev useInView triggers camera flyTo, zone selection, timeline year, and layer changes per chapter. Entry from Header, story beat 3, or direct URL.

• Voice Narration (ElevenLabs) — Three-tier TTS system with global mute toggle and per-surface playback controls:

  • Tier 1 — Narrator: Pre-generated audio for all 6 story beats and 8 Bronzeville chapters. Auto-plays on beat change (story mode) or scroll-into-view (scrollytelling). 14 clips cached in Convex file storage via npm run seed:narration.
  • Tier 2 — Appraiser: On-demand TTS for 112 HOLC area descriptions. "Listen to appraisal" button generates audio on first click, permanently cached thereafter. Rate-limited per session.
  • Tier 3 — Chat: On-demand streaming TTS for AI guide responses. Listen/read mode toggle, per-message replay buttons, auto-interrupt on zone change. Rate-limited (10/min, 50/hr per session).
  • iOS autoplay unlock via silent MP3 on first user gesture. Single shared <audio> element managed by NarrationProvider context.

• Research-Sourced Citations — Every data panel and story beat cites peer-reviewed Milwaukee research with in-app PDF viewer modal (9 papers total, including 6 on Bronzeville history)

• Time Slider — GSAP-animated timeline (1870-2025) with zone opacity pulsing by development era, covenant accumulation count, and era annotations

• Layer Controls — Toggle zones, labels, neighborhoods, buildings, covenants, base map, and all overlays independently

• Responsive Design — Desktop split-panel layout, tablet adaptation, mobile bottom-sheet pattern

Tech Stack

Layer	Technology
Framework	Next.js 16 (App Router, Turbopack) + TypeScript
Backend	Convex (database, server functions, file storage)
Map	Mapbox GL v3 via react-map-gl
Buildings	PMTiles vector tiles (148K parcels)
Animation	GSAP (GreenSock) + Motion.dev (spring physics, gestures)
AI	Claude API (Sonnet 4) via Convex actions
Voice	ElevenLabs TTS (Multilingual v2) via Convex actions
Styling	Tailwind CSS v4
Testing	Vitest + Testing Library
Deployment	Vercel + Convex Cloud

Quick Start

Prerequisites

• Node.js 20+
• npm
• Convex account (free tier)
• Mapbox access token (for map rendering)
• Anthropic API key (for AI guide)
• Census API key (free, optional for data pipelines)

Installation

git clone https://github.com/tmoody1973/redlined.git
cd redlined
npm install

Environment Variables

Create .env.local in the project root:

CONVEX_DEPLOYMENT=           # From `npx convex dev`
NEXT_PUBLIC_CONVEX_URL=      # From `npx convex dev`
NEXT_PUBLIC_MAPBOX_TOKEN=    # Mapbox GL access token

Set API keys in your Convex dashboard (Settings > Environment Variables):

Variable	Description	Required
ANTHROPIC_API_KEY	Claude API key for AI narrative guide	Yes
ELEVENLABS_API_KEY	ElevenLabs API key for voice narration	Yes
CENSUS_API_KEY	US Census API key for data pipelines	Optional

Development

# Terminal 1: Start Convex dev server
npx convex dev

# Terminal 2: Start Next.js dev server
npm run dev

Seed Data

# Load HOLC zones and area descriptions into Convex
npm run seed

# Load Census income data
npm run seed:census

# Seed health and environment data
npx tsx scripts/seed-health.ts
npx tsx scripts/seed-environment.ts

# Pre-generate narrator voice clips (requires ELEVENLABS_API_KEY in Convex)
npm run seed:narration

Data Pipelines

Pre-computed data files in public/data/ are generated by scripts:

npx tsx scripts/build-zone-timeline.ts      # Zone development timeline
npx tsx scripts/build-ghost-zone-stats.ts   # Ghost building statistics
npx tsx scripts/build-value-history.ts      # 1938 vs today property values
npx tsx scripts/build-race-data.ts          # Racial demographics by zone
npx tsx scripts/build-sanborn-context.ts    # Sanborn map context by zone
npx tsx scripts/build-decades-census.ts     # Decade-by-decade income/ownership (Census API)
npx tsx scripts/build-hrs-overlay.ts        # Historic Redlining Scores (openICPSR)
npx tsx scripts/download-2020-crosswalk.ts  # Download 2020 Census tract crosswalk
npx tsx scripts/process-covenants.ts       # Geocode racial covenants → GeoJSON (Census Bureau API)

Building Parcels

The 148K building extrusions use a PMTiles vector tileset (public/data/milwaukee-parcels.pmtiles, 23 MB, included in the repo). Each parcel includes street address (HOUSE_NR_LO, SDIR, STREET, STTYPE), TAXKEY, year built, assessed value, building type, and HOLC zone assignment. The source GeoJSON (data/milwaukee-parcels.geojson, 119 MB) is excluded from git due to GitHub's file size limit. To regenerate it locally:

npx tsx scripts/fetch-parcels.ts            # Downloads MPROP parcels → data/milwaukee-parcels.geojson
tippecanoe -o public/data/milwaukee-parcels.pmtiles -Z11 -z16 -l parcels --drop-densest-as-needed data/milwaukee-parcels.geojson

Project Structure

redlined/
├── app/                         # Next.js App Router
│   ├── page.tsx                 # Main application page
│   ├── bronzeville/page.tsx     # Bronzeville scrollytelling deep dive
│   ├── globals.css              # Tailwind + design tokens
│   └── api/tiles/               # PMTiles tile server endpoint
│
├── components/
│   ├── map/                     # Map rendering
│   │   ├── MapView.tsx          # Mapbox GL map with overlays
│   │   └── BuildingLayer.tsx    # Building extrusions + ghost circles
│   ├── panel/                   # Side panel (three-act narrative)
│   │   ├── InfoPanel.tsx        # Panel router (zone/building)
│   │   ├── ZoneDetail.tsx       # Three-act narrative orchestrator
│   │   ├── NarrativeHeader.tsx  # Act 1: dynamic 1938 decision sentence + HRS badge
│   │   ├── ContentWarning.tsx   # Grade-aware content warning with narrative framing
│   │   ├── CollapsibleSection.tsx # Reusable disclosure for Act 2
│   │   ├── OverlayNarrative.tsx # Act 3: plain-language headline wrapper
│   │   ├── DecadesPanel.tsx     # Decades of change charts and tables
│   │   ├── AppraiserDescription.tsx # Original 1938 appraiser text
│   │   ├── BuildingDetail.tsx   # Individual building properties
│   │   ├── ChatPanel.tsx        # AI narrative guide ("Ask the Guide")
│   │   ├── SuggestedQuestions.tsx # Zone-aware question pills
│   │   ├── IncomeStatistics.tsx # Income overlay panel
│   │   ├── HealthStatistics.tsx # Health overlay panel
│   │   ├── EnvironmentStatistics.tsx
│   │   ├── ValueStatistics.tsx  # Assessed value + 1938 comparison
│   │   ├── RaceStatistics.tsx   # Race demographics + 1938 HOLC data
│   │   ├── DemolitionStatistics.tsx # Ghost building stats
│   │   ├── SanbornContext.tsx   # Sanborn map narrative context
│   │   └── SourceCitation.tsx   # Research PDF citation links
│   ├── ui/                      # Overlay UI elements
│   │   ├── LayerControls.tsx    # Layer + overlay toggles
│   │   ├── TimeSlider.tsx       # Animated timeline bar
│   │   ├── HOLCLegend.tsx       # Grade color legend
│   │   ├── IncomeLegend.tsx     # Data overlay gradient legend
│   │   ├── GhostLegend.tsx      # Demolished buildings legend (with close button)
│   │   ├── AboutModal.tsx       # "About the Map" modal with data sources
│   │   ├── ResearchModal.tsx    # PDF viewer modal for research papers
│   │   ├── NarrationToggle.tsx  # Global mute/unmute pill button (3 states)
│   │   ├── AudioWaveform.tsx    # 5-bar animated waveform indicator
│   │   └── PlayPauseButton.tsx  # Reusable play/pause with loading spinner
│   ├── story/                    # Guided story mode overlay
│   │   ├── StoryOverlay.tsx      # Main overlay (keyboard, swipe, skip)
│   │   ├── StoryCard.tsx         # Beat content card (Motion.dev transitions)
│   │   └── StoryStepIndicator.tsx # Progress dots (layoutId animation)
│   ├── archive/                  # "The Archive" gallery modal
│   │   ├── ArchiveModal.tsx      # Root shell: overlay, tabs, AnimatePresence
│   │   ├── ArchiveTabBar.tsx     # Tab nav with animated underline (layoutId)
│   │   ├── OriginalMapSection.tsx # Pinch/zoom/drag HOLC scan viewer
│   │   ├── PhotoGallerySection.tsx # FSA photo grid with filters
│   │   ├── PhotoCard.tsx         # Spring-animated "print" card
│   │   ├── PhotoLightbox.tsx     # Full-screen photo viewer with nav
│   │   ├── TimelineSection.tsx   # Era-based timeline browser
│   │   ├── TimelineCard.tsx      # Expandable event card
│   │   └── TimelineProgressBar.tsx # Era navigation pills
│   ├── bronzeville/             # Bronzeville scrollytelling components
│   │   ├── ChapterSection.tsx   # Scroll-driven chapter with useInView
│   │   ├── ScrollProgress.tsx   # Reading progress bar
│   │   ├── BronzevilleHero.tsx  # Opening hero section
│   │   └── BronzevilleOutro.tsx # Closing stat grid + CTAs
│   └── layout/                  # App shell + navigation
│
├── convex/                      # Convex backend
│   ├── schema.ts                # Database schema (zones, messages, rateLimits, audioCache)
│   ├── queries.ts               # Data queries
│   ├── mutations.ts             # Data mutations (with input validation)
│   ├── ai.ts                    # Claude AI actions (rate limited, topic guarded)
│   ├── tts.ts                   # ElevenLabs TTS actions (3 tiers, cached, rate limited)
│   ├── rateLimit.ts             # Per-session rate limiting (internalMutation)
│   └── seed.ts                  # Seed data functions
│
├── lib/                         # Client utilities
│   ├── narrative-text.ts        # Pure text generation for narrative panel
│   ├── zone-selection.tsx       # Zone/building selection context
│   ├── data-overlay.tsx         # Overlay state context
│   ├── time-slider.tsx          # Timeline state context
│   ├── layer-visibility.tsx     # Layer toggle context
│   ├── map-camera.tsx           # Camera flyTo context (used by story mode + scrollytelling)
│   ├── story-beats.ts           # 6-beat narrative script with camera targets
│   ├── story-mode.tsx           # Story state + orchestration context
│   ├── bronzeville-chapters.ts  # 8-chapter Bronzeville scrollytelling data
│   ├── colorScale.ts            # Overlay color mapping functions
│   ├── census-helpers.ts        # Crosswalk + weighted averages
│   ├── useZoneIncome.ts         # Income data hook
│   ├── useZoneHealth.ts         # Health data hook
│   ├── useZoneEnvironment.ts    # Environment data hook
│   ├── useZoneValue.ts          # Property value data hook
│   ├── useZoneValueHistory.ts   # 1938 vs today value hook
│   ├── useZoneRace.ts           # Race demographics hook
│   ├── useZoneHRS.ts            # Historic Redlining Score hook
│   ├── useDecadesData.ts        # Decade trends data hook
│   ├── useSanbornContext.ts     # Sanborn map context hook
│   ├── research-context.tsx     # Research PDF modal context provider
│   ├── narration.tsx            # NarrationProvider context (shared audio, mute, iOS unlock)
│   ├── useNarratorAudio.ts     # Tier 1 hook (pre-generated narrator clips)
│   ├── useAppraiserAudio.ts    # Tier 2 hook (on-demand appraiser TTS)
│   ├── useChatAudio.ts         # Tier 3 hook (chat TTS with listen mode)
│   └── ai-prompt.ts             # AI system prompt with research findings
│
├── scripts/                     # Data pipeline + asset scripts
│   ├── optimize-holc-scan.ts    # sharp: 43MB scan → 2K + 4K JPEGs
│   ├── curate-archive-photos.ts # Download LOC photos, generate manifest
│   ├── run-seed.ts              # Convex data seeding
│   ├── seed-census.ts           # Census API → Convex
│   ├── seed-health.ts           # CDC PLACES → Convex
│   ├── seed-environment.ts      # EPA EJScreen → Convex
│   ├── seed-narration.ts         # Pre-generate 14 narrator TTS clips
│   ├── fetch-parcels.ts         # Milwaukee MPROP → PMTiles
│   ├── detect-ghost-buildings.ts # Demolished building detection
│   ├── build-zone-timeline.ts   # Development era timeline
│   ├── build-ghost-zone-stats.ts # Ghost building statistics
│   ├── build-value-history.ts   # 1938 property value comparison
│   ├── build-race-data.ts       # Racial demographics pipeline
│   ├── build-sanborn-context.ts # Sanborn map context pipeline
│   ├── build-decades-census.ts  # Decade-by-decade Census pipeline
│   ├── build-hrs-overlay.ts     # Historic Redlining Scores pipeline
│   ├── download-2020-crosswalk.ts # 2020 Census tract crosswalk
│   └── process-covenants.ts     # Geocode racial covenants (Census Bureau batch API)
│
├── data/                        # Source data files
│   ├── milwaukee-holc-zones.json      # 114 zone GeoJSON
│   ├── holc-area-descriptions.json    # 1938 appraiser records
│   ├── census-holc-crosswalk.json     # Tract-to-zone mapping
│   ├── milwaukee-parcels-by-zone.json # MPROP aggregates
│   ├── ghost-buildings.json           # Demolished structures
│   ├── research-context.json          # Structured research findings
│   ├── covenants/                     # UWM racial covenant records
│   │   └── covenants-wi-milwaukee-county.csv  # 32,506 raw records (42 MB)
│   └── hrs/                           # openICPSR HRS Excel files
│       ├── Historic Redlining Indicator 2000.xlsx
│       ├── Historic Redlining Indicator 2010.xlsx
│       └── Historic Redlining Indicator 2020.xlsx
│
├── public/archive/              # Optimized archive assets
│   ├── holc-scan-2k.jpg         # 2048px HOLC scan (1.0 MB)
│   ├── holc-scan-4k.jpg         # 4096px HOLC scan (4.1 MB)
│   └── photos/                  # 20 LOC FSA photos (thumb + full)
│
├── public/data/                 # Pre-computed JSON (served statically)
│   ├── zone-development-timeline.json
│   ├── ghost-buildings-by-zone.json
│   ├── value-history-by-zone.json
│   ├── race-by-zone.json
│   ├── sanborn-context-by-zone.json
│   ├── decades-research-stats.json
│   ├── decades-by-zone.json
│   ├── hrs-by-zone.json
│   ├── milwaukee-parcels-by-zone.json
│   ├── research-context.json
│   ├── covenants/                # Racial covenant map data
│   │   ├── milwaukee-covenants.geojson  # 32,219 geocoded Points (15 MB)
│   │   └── covenant-stats.json          # Summary statistics
│   └── archive/                  # Archive gallery data
│       ├── fsa-photos.json       # 20 curated LOC photo manifest
│       └── timeline-events.json  # 12 events across 5 eras
│
└── public/research/             # Academic research PDFs (in-app viewer)
    ├── chang-smith-2016.pdf
    ├── lynch-et-al-2021.pdf
    ├── paulson-wierschke-kim-2016.pdf
    └── bronzeville/             # Bronzeville-specific research
        ├── barbera-2012.pdf     # Jazz and Community, 1950-1970
        ├── niemuth-2014.pdf     # Urban Renewal, 1960-1980
        ├── honer-2015.pdf       # Kilbourntown-3 and Midtown
        ├── ethnic-african-american.pdf  # Community portrait
        ├── hood-design-2024.pdf # Bronzeville Center research
        └── black-heritage.pdf   # Visual heritage documentation

Data Sources

All data is freely available and publicly accessible.

Dataset	Source	Use
HOLC Zones (Milwaukee)	Mapping Inequality	114 zone polygons with grades A-D
HOLC Area Descriptions	americanpanorama/HOLC_Area_Description_Data	Original appraiser text (112 Milwaukee records)
Census-HOLC Crosswalk	americanpanorama/mapping-inequality-census-crosswalk	Links HOLC zones to Census tracts (717 records)
Census ACS 5-Year	api.census.gov	Income, race/ethnicity by tract (B19013, B02001, B03002)
CDC PLACES	cdc.gov/places	Health risk indicators by tract
EPA EJScreen	epa.gov/ejscreen	Environmental burden percentiles by tract
Historic Redlining Scores	openICPSR #141121	Continuous 1.0–4.0 redlining severity per tract (2000, 2010, 2020)
Milwaukee MPROP	data.milwaukee.gov	148K property parcels with addresses, assessed values
MPROP Historical	data.milwaukee.gov	1975-2024 property snapshots (ghost detection)
LOC FSA/OWI Photos	Library of Congress	20 curated Carl Mydans Milwaukee photos (1936)
HOLC Security Map Scan	Mapping Inequality	Original 1938 HOLC scan (optimized 2K + 4K)
Racial Covenants	UWM Mapping Racism & Resistance	32,219 geocoded covenant deeds (1910-1959)
HOLC Zones (All Cities)	Mapping Inequality	10,154 zones across 300 cities (Phase 3)

Data Overlay Details

Race & Demographics

Compares 1938 HOLC racial assessments with modern Census data:

• 1938: Appraisers recorded "Negro" presence, "infiltration" groups, and foreign-born populations as factors in downgrading neighborhoods
• Today: A-zones average 74.9% White / 14.8% Black; C-zones average 54.6% White / 28.1% Black
• Zone D5: Explicitly flagged for "Negro" presence (65%) in 1938 — today 68.2% Black. Segregation persisted for 87 years.

1938 vs Today Property Values

Parses 1930s appraiser-estimated prices from HOLC area descriptions alongside modern MPROP assessed values:

• Nominal growth: D-zones grew 51.5x (from $6,618 avg to $340,750)
• Inflation-adjusted: Many zones show real value erosion when adjusted for 22.3x CPI factor
• Grade correlation: A-zone average values remain significantly higher than D-zone values

Racial Covenants

32,219 racial covenants in Milwaukee County property deeds, crowdsourced by ~5,000 volunteers through UWM's Mapping Racism & Resistance project and geocoded at 99.4% match rate via the US Census Bureau batch geocoder:

• By decade: 1910s: 238, 1920s: 23,035, 1930s: 5,290, 1940s: 3,532, 1950s: 124
• By city: Milwaukee: 21,192, Wauwatosa: 4,235, West Allis: 2,774, plus 14 other municipalities
• Timeline integration: Scrub the time slider through 1910-1959 to watch covenants accumulate — 71% were filed in the 1920s alone, showing how legal segregation preceded and informed HOLC redlining
• Visualization: Amber heatmap at low zoom (density), individual dots at high zoom (click for deed text with content warning)

Historic Redlining Scores

Area-weighted continuous score (1.0–4.0) per Census tract measuring redlining intensity, joined to HOLC zones via the Census crosswalk:

• A-zone average: 1.74 (minimal redlining exposure)
• B-zone average: 2.25
• C-zone average: 2.99
• D-zone average: 3.70 (severe redlining exposure)
• Lynch et al. found 73% higher odds of current lending discrimination for every one-unit increase in HRS

Research Sources

Nine academic papers on Milwaukee's redlining and Bronzeville history are integrated into the application. Each data overlay panel and guided story beat includes inline citations with key findings, and clicking "View PDF" opens the full paper in a modal viewer. The AI narrative guide also references these findings when answering questions.

Paper	Authors	Year	Topics
Neighborhood Isolation and Mortgage Redlining in Milwaukee County	Woojin Chang & Michael Smith	2016	Income gaps, home ownership, persistent isolation
The Legacy of Structural Racism: Redlining, Lending, and Health	Emily Lynch et al.	2021	Health outcomes, lending discrimination, infant mortality
Milwaukee's History of Segregation: A Biography of Four Neighborhoods	Jessie Paulson, Meghan Wierschke & Gabe Kim	2016	Bronzeville, I-43 highway, suburban exclusion
An Improvised World: Jazz and Community in Milwaukee, 1950-1970	Benjamin Barbera	2012	Jazz clubs, Bronzeville culture, I-43 displacement
Urban Renewal and Milwaukee's African American Community: 1960-1980	Niles Niemuth	2014	I-43 highway, Harambee, employment collapse, Black agency
The Unworkable Program: Urban Renewal in Kilbourntown-3 and Midtown	Matthew Honer	2015	Federal policy, segregation, containment, K-3 clearance
Milwaukee African Americans: A Community Portrait	City of Milwaukee / Historical Society	2000	Walnut Street, Great Migration, community institutions
Milwaukee History Maps: Research Synthesis	Hester Tittmann / Hood Design Studio	2024	Bronzeville mapping, cultural development timelines
Black Heritage in Milwaukee	Milwaukee Heritage Collection	1990	Visual heritage documentation, demolished community spaces

PDFs are served from public/research/ (3 general + 6 Bronzeville) and metadata is structured in public/data/research-context.json.

AI Chat Protection

The AI Narrative Guide is a public-facing tool with no authentication (intentional for a public educational app). Four layers of protection prevent abuse without requiring login:

Layer	Where	What
Rate Limiting	convex/rateLimit.ts	Fixed-window limits per session: 5/min, 30/hour, 100/day. Checked atomically via internalMutation before every Claude API call.
Input Validation	convex/mutations.ts + convex/ai.ts	User messages capped at 1,000 chars. Conversation history truncated to last 20 messages (bounds token cost). Role validated as enum.
Topic Guardrails	convex/ai.ts + system prompt	Server-side keyword pre-check blocks prompt injection ("ignore previous instructions") and off-topic requests ("write me a", "code a") before hitting Claude. System prompt includes BOUNDARIES section instructing Claude to refuse non-redlining topics.
Bot Protection	ChatPanel.tsx	Honeypot hidden input (bots auto-fill, humans don't see). 3-second minimum interaction time rejects instant submissions. Client-side maxLength=500 for UX feedback.

Roadmap

Phase 1: MVP — Milwaukee HOLC Explorer (Complete)

3D zone visualization, 148K building extrusions with street addresses, click-to-inspect zones and buildings, AI narrative guide with zone-aware questions, five data overlays (income, health, environment, value, race), 32,219 racial covenants with timeline scrubbing, ghost buildings with dismiss button, time slider, Sanborn map context, research-sourced citations with PDF viewer, plain-English narrative panel for museum audiences with Historic Redlining Scores, interactive Archive gallery (original HOLC map viewer, 20 LOC photographs, historical timeline), About modal, responsive layout.

Phase 2: Enhanced Narrative

ElevenLabs voice narration (complete — 3-tier TTS with 14 pre-generated narrator clips, on-demand appraiser and chat audio), historical MPROP time-series (1975-2024 sparklines), Sanborn fire insurance map overlay. Guided Bronzeville narrative tour (complete — see Guided Story Mode). Bronzeville scrollytelling deep dive (complete — 8-chapter /bronzeville route).

Phase 3: Multi-City

Expand to Chicago, Detroit, Atlanta using the 10,154-zone national dataset. Embeddable iframe mode. "What If" counterfactual visualization.

Content Advisory

This application displays the original language used by HOLC appraisers in the 1930s, which includes explicitly racist descriptions of neighborhoods and their residents. This language is presented with content warnings as historical evidence — the words should be uncomfortable because the policy was.

License

Data sources are subject to their respective licenses:

• Mapping Inequality / American Panorama data: CC-BY-NC
• Census data: Public domain
• openICPSR Historic Redlining Scores: Terms of Use
• UWM/UMN Racial Covenants: ODC-By
• Application code: MIT

Acknowledgments

• Mapping Inequality — University of Richmond Digital Scholarship Lab
• American Panorama — Open-source historical data
• Library of Congress — FSA/OWI photograph collection (Carl Mydans, Milwaukee 1936)
• UWM Mapping Racism & Resistance — 32,219 racial covenant records crowdsourced by ~5,000 volunteers
• Bronzeville Center for the Arts — Research synthesis by Hood Design Studio
• UWM Libraries — Bronzeville thesis collection (Barbera, Niemuth, Honer)
• Radio Milwaukee / The Intersection