Project · 03 · iOS App

Footprints

An app that turns a city into a map of the small things people did there. Write a list — "100 things before I graduate" — pin each thing to a landmark, walk it with a guide, and leave a trace. Every city you finish becomes a small 3D slab on your page.

Year2026

MediumiOS App · Clickable Prototype

DisciplineProduct · Interaction · UI/UX

SiteUC Berkeley

Try the app ↓

Concept

Maps tell you what is somewhere. They don't tell you what people did there.

01 · Market Research · Landscape

The map has become social — and mostly real-time

The largest players have turned maps into a social layer, but almost all of them are built around the present moment: where a friend is right now, what is happening nearby. Personal history — the 5:50 carillon, the $4 bánh mì on the steps — still lives in group chats and graduates with the people who had it.

400M+

Monthly active users on Snap Map as of May 2025 — including "Footsteps", a view of how much of the world you've explored.

Snap Newsroom · 2025

Aug 2025

Instagram launches its own Map, letting users share their last active location with chosen friends — opt-in, inside DMs.

Meta Newsroom · 2025

20M+

Travelers on Polarsteps, which records routes automatically and turns them into keepsake travel books — proof people pay to relive movement.

Polarsteps · 2026

3 mo.

New default auto-delete for Google Maps Timeline after it moved on-device; the web version ended June 9, 2025.

Android Police · Daftei · 2025

01 · Market Research · Competitors

Where each map stops

Product	Core job	Time frame	Gap
Snap Map	See friends nearby, discover local hotspots	Now	Discovery is ambient; nothing to finish, no reason to return
Instagram Map	Share last active location, browse tagged content	Now · 24h	Privacy anxiety on launch; content expires rather than accumulates
Polarsteps	Track and relive trips	Past · per trip	Built for travel, not the everyday places you return to
Google Timeline	Private log of every visit	Past · 3 mo. default	Solitary, utilitarian, and increasingly short-lived
Footprints	Lists you walk; traces that stay on the place	Past · cumulative	—

01 · Market Research · Positioning & Model

Cities collected as 3D map slabs — Berkeley, San Francisco, Oakland, Lake Tahoe

Campus first — because campuses have rituals and a clock

Students with a clock running on a place; then visitors, new arrivals and locals who want the version of a city insiders know. Free to make, walk and share; revenue comes from people who want more of the Guide, from places that want to be on a good list, and from the souvenirs a day leaves behind.

Footprints+ · core

The Guide without limits — unlimited routes and photo check-ins, offline city packs, private lists, the full postcard archive. $4.99 / month · student $2.99.

One loop. Every finished thing becomes a trace

Every trace makes the map richer for the next person — which is what brings them in. Step 6 feeds step 1: the loop closes when someone else discovers what you left.

Discover

Open the map. Landmarks show how many people left traces there. Tap one to read them.

Map · place sheet

Collect

Save someone's list, or make your own and pin each thing to a place.

Lists · new list

Walk

Ask the Guide. It plans a route through your list using what others did.

Guide

Check in

Take a photo at the place. The Guide recognises it and ticks the thing off.

Check-in

Leave a trace

Add a line and a rating. It appears on the landmark for the next person.

Place · your page

06 ↺

At the end of the day the Guide draws a postcard. Save it, or send the link.

Postcard

02 · Interaction Model · Three Objects

Place, list, trace

Three objects hold the whole product. A landmark stands on real geography as an inked isometric building — tower, colonnaded library, awninged shopfront, a mound for the Big C — with a flag above counting the traces left there.

Place

A landmark on the map at true coordinates. Tap it to read what people did there.

List

Things worth doing, each pinned to a place. Progress is counted in isles, not checkboxes.

Trace

One person doing one thing at one place, with a photo and a line. A check-in needs a photo the Guide recognises there. Ratings come only from people who finished the thing — no trace, no review.

02 · Interaction Model · The Map Algorithm

A 2D paper map — where only landmarks stand up

Nothing on the map is decorative. The base is real geography (Esri street tiles), desaturated and washed to paper so streets read as faint 2D lines. A place rises into 3D only when people have left traces there; its shape, height and label are all derived from data.

Rule 01

Flat by default

Every tile passes through grayscale → contrast → paper overlay. Roads, water and blocks stay two-dimensional; nothing competes with a landmark.

Rule 02

Traces raise a place

A place gets a 3D isle only if count > 0. The flag above it shows the count; the building type is chosen from the place's kind — tower, library, street, park, bakery, hill, lawn.

Rule 03

Scale with zoom

Isle size follows 0.55 + (zoom − 15) × 0.3, clamped to 0.55–1, so buildings shrink as you pull out and never bury the streets.

Rule 04

Labels yield

Names are placed by trace count, highest first; any label that would overlap a busier one hides. A route is drawn only for the list you are walking today.

02 · Interaction Model · The Guide

A small wordless light that remembers

Lumen never speaks. It plans a route through other people's traces, recognises your photo when you check in, and turns the day into a postcard. On the map it is the only thing that glows — cyan on paper, the one colour reserved for interaction.

Trust

A check-in requires a photo the Guide recognises at that place. Photo recognition is simulated in the prototype with per-place tags.

Privacy

Nothing is live. The app only knows where you chose to leave a trace, and you decide which parts of your page a visitor sees.

Try it · Clickable Prototype

Sign in as Mia and walk her list

Tap Sather Tower, open a person, follow their list, check in with a photo and let Lumen draw the postcard. Tabs, guide chips, checkboxes and "New list" all work. Best on the phone to the right; on a small screen it fills the width.

Open full screen →

03 · UI / UX Design · Clickable Flow

Sign in → map → a person → their list → check in → postcard

Three moments from the flow, each opened directly. Tabs, guide chips, list checkboxes and "New list" all work — click through any phone.

Map · Sather Tower openTraces left at the landmark, and the people behind them

Check-inPhoto recognised at the place · matched to #03 on the list

PostcardThe day, drawn by the Guide on a hand-drawn map

03 · UI / UX Design · Your Page

Every city you finish becomes a 3D slab

Your page opens on the cities you've collected — each a small isometric block of real map tiles carrying the landmarks you left traces on: Berkeley's tower, San Francisco's downtown, Oakland, the trees of Tahoe. Below: your stories on a map, lists you made, lists you saved. A settings screen shows the page exactly as a visitor would see it.

Design system

Source Serif as the chrome, cyan for interaction, magenta as the rare stamp colour, 2px radii, whitespace instead of dividers. The hand-drawn softness lives only in the isles, the sprite and the postcard.

Three skins explored

Newsprint paper, dawn sky, ink-and-wash. Paper was chosen — quietest, most editorial.

Reflection

The map doesn't need to know
where anyone is.
It only needs to remember.

Berkeley first, seeded with twenty lists before launch. Then the next five campuses, then the cities students travel to. The loop is the product.

— 2026 · Zhang Yichi