Computational geometry is the last thing you'd put inside a smart contract. It's complex, it's expensive, and conventional wisdom says handle it off-chain: run the collision check in your backend, then submit a transaction only if it passes. Keep the chain lean. Keep the math elsewhere.

merca.earth does the opposite. The Separating Axis Theorem — a full convex-polygon collision algorithm — runs inside every parcel registration. On-chain. In integer arithmetic. Without floating-point.

This isn't a performance stunt. It's the only way to make the non-overlap guarantee unconditional. Here's why.

A spatial cadastre — a protocol where territory claims on a map must never overlap — imposes requirements that most blockchains weren't designed for. It needs atomic read-check-write in a single transaction. It needs concurrent writes to shared state without serialization. It needs sub-second finality for a real-time map. And it needs programmable authorization that works without the owner's signature. We evaluated EVM chains, Solana, and Sui. Here's what we found.

What does it mean to put your name on a place?

Not to own it in any legal sense — to mark it. To say: this location carries meaning, and that meaning is ours. People have done this for as long as they've had places to mark. The tools change. The impulse doesn't. And the interesting thing isn't the marking itself — it's what happens when someone else disagrees.

"Not for sale."

Two words that feel like power. You own something, and you can refuse the world. No one can touch it. No offer is high enough. The thing is yours, and your refusal is the proof.

But here's what that refusal actually communicates: nothing. You've told the world you won't sell. You haven't told it what the thing is worth to you. You haven't been tested. You've just gone quiet.

In 2005, a 21-year-old student at the University of Nottingham had $0 for tuition and a browser open. Alex Tew built a webpage with a 1,000×1,000 pixel grid — one million pixels total — and sold each pixel for $1. Minimum purchase: a 10×10 block for $100. Buyers put whatever they wanted in their block: a logo, a URL, a name, a joke. Companies bought hundreds of pixels. Individuals bought ten. The grid filled up. Tew earned $1,037,100. Then the experiment ended, because the grid was full.

It was a strange, beautiful thing. People paid real money for a spot on a shared canvas. Not for traffic, not for conversions — for the fact of being there, visible, alongside everyone else who had paid to be there. The scarcity was artificial but the desire was real.

And then it was over. Frozen. A JPEG of 2005.

Welcome to the official merca.earth documentation. Here you'll find guides for using the app, understanding the economics, and deep-diving into the protocol.

We exist to make meaning visible — by letting the world see which ideas people value enough to defend.

Start with What is merca.earth? or jump to Getting Started.