Cartogram: Turning Maps into Art, One Wallpaper at a Time

You look at your phone before you look at anything else in the morning. Before coffee. Before the news. Before you say a word to anyone. Your eyes open and there it is: your lock screen.

Most of us never think about that moment. We accept the default gradient or the photo from three holidays ago and move on. But that screen is the most personal canvas you own. You see it a hundred times a day. Shouldn't it mean something?

That question is the entire reason Cartogram exists.

Where It Started

I have always loved maps. Not as tools for getting from A to B, but as objects. The way a city's street grid reveals its history. The way coastlines look like something drawn by hand. The way a well-styled map can be genuinely beautiful.

One day I looked at my phone and thought: what if my wallpaper was a map of where I am right now? Not a screenshot of Google Maps. Something crafted. Something that felt like art, not utility.

That was the spark. Everything that followed -- the rendering engine, the style library, the live wallpaper service, the instant app, the freemium pivot -- all of it grew from that single, simple desire: to make the thing you look at most into something worth looking at.

Making Maps Beautiful

The technical challenge was clear from the start. A wallpaper has to be lightweight. It runs behind everything else on your phone. It cannot drain your battery or slow down your day. We needed to render detailed, styled maps while being invisible to the system's performance budget.

We spent months on this. Tweaking the rendering pipeline. Testing across devices from flagship to budget. Ensuring that a beautifully styled map of Tokyo looked just as sharp on a mid-range phone as it did on a Pixel.

But the engineering was in service of something more important: the styles themselves.

We built over 25 curated map styles. Each one is a deliberate creative choice -- colour palette, line weight, label treatment, the balance between detail and simplicity. Some are inspired by vintage cartography, some by modern graphic design, some by the desire to make an AMOLED screen glow with nothing but the outlines of streets.

And then we gave users the tools to make their own. A full colour editor where you can customise every element of the map -- from landscape to administrative boundaries to points of interest. Your city, your colours, your wallpaper.

Going Live

Static wallpapers were the beginning. But maps are not static things. You move through the world. The weather changes. Day turns to night.

So we built live wallpapers. Your background subtly updates as you move through your day. The map shifts to reflect where you are. It breathes.

There is something quietly delightful about glancing at your phone and seeing your neighbourhood rendered in a style you chose, updated to where you are right now. It is a small thing. But small things, done well, accumulate.

The Trust Problem

Here is something they do not tell you about selling a paid app on Android: the refund window is brutal. Users have a short window to decide if your app is worth the money, and that clock starts ticking the moment they hit "Install." Not the moment they open it. Not the moment they understand it.

For an app like Cartogram, where the magic is in the experience -- in scrolling through styles, finding the one that feels right, setting it as your wallpaper and then seeing it on your home screen throughout the day -- a few minutes is not enough. People were buying, not having time to explore, and requesting refunds. Not because the app was bad. Because they had not had the chance to fall in love with it.

We needed to let people try before they bought. We needed to build trust.

An Instant App in One Line of Code

Android Instant Apps let users try your app without installing it. When we first investigated this in early 2019, the constraints were severe. A 4MB size limit. Mandatory feature modules. Significant refactoring.

But the platform matured. The size limit grew to 10MB. App Bundles simplified the architecture. And for a single-module app like Cartogram, which weighed in at a lean 2.82MB, the path became remarkably simple.

One line. In the AndroidManifest:

<dist:module dist:instant="true" />

That is it. That single declaration turned Cartogram into a try-before-you-buy experience. A "Try Now" button appeared on our Play Store listing, right next to "Install." Users could explore the app, browse styles, see how a map wallpaper looked on their phone -- all without committing a cent.

The conversion prompt handled the rest gracefully. When a user tried to set a wallpaper (which requires the SET_WALLPAPER permission, not available to instant apps), the system surfaced a clean install prompt from Google Play Services:

implementation "com.google.android.gms:play-services-instantapps:${current_version}"

It was an honest moment. The user had already experienced the app. They knew what they were getting. The purchase decision became informed rather than hopeful.

Did It Work?

The honest answer: it helped, but it was not a silver bullet.

A healthy percentage of instant app users converted to the paid version. Refunds decreased. But some users still bought and returned, often for reasons that had nothing to do with the app itself -- buyer's remorse, changed minds, the simple friction of any transaction.

What the instant app really did was something harder to measure: it built trust. The "Try Now" button said something about us as developers. It said: we are confident enough in this app to let you experience it for free. We are not hiding anything. We believe you will like it.

That is worth more than any conversion metric.

What I Learned

Building Cartogram taught me things that no tutorial or course could have:

Small apps can have big impact. Cartogram is not a social network or a productivity suite. It is a wallpaper app. But it has been downloaded over 50,000 times, reviewed over 1,000 times, and rated 4.6 stars. People care about beauty in the small moments. Never underestimate that.

Friction is the enemy of love. Every barrier between a user and the experience of your product is a reason for them to walk away. The instant app removed the biggest barrier we had -- the requirement to pay before experiencing. One line of XML. Massive difference in trust.

Paid apps require confidence. You are asking someone to pay before they know you. That is a big ask. Everything about your store listing, your screenshots, your description, your instant experience needs to radiate competence and care. Because that is what they are really buying: confidence that this developer gives a damn.

Listen, then build. Users told us about bugs with wallpaper updates. About the colour editor being tricky. About wanting automatic light and dark theme switching. Every piece of feedback was a gift. An indie studio's resources are limited, but our attention does not have to be.

The Road Forward

Cartogram started as a question about what belongs on the most personal screen you own. It has grown into something I am proud of -- an app that treats a small daily moment with real creative care.

The journey continues. There are styles to design, features to build, users to listen to. But the core idea has not changed: your phone is a canvas. Your city is the art. And the map of where you are is, in its own quiet way, a portrait of who you are.

Cartogram is available on the Google Play Store. You can try it instantly, no install required.

I am Kevin Murphy, an indie developer based in Ireland, building things I care about at Round Tower.