Where the city comes from

The streets, the canals, the bridges, the tram tracks and the footprints of the buildings come from OpenStreetMap.

Map data © OpenStreetMap contributors, available under the Open Database License (ODbL) 1.0. OpenStreetMap’s copyright page explains what that licence asks of a user.

The data files inside the game are a derivative database in the sense of that licence, and they ship unencrypted. So they are available here as a download under the same licence, with the licence text, a readme and a manifest. This page used to say you could ask the helpdesk for them; that was replaced by a button, because the licence asks that a machine-readable copy be offered.

Two kinds of photograph were laid beside the work, to check that the city sat in the right place and that the roofs and façades really look the way they do. The straight-down aerial imagery comes from PDOK (Publieke Dienstverlening Op de Kaart), the Dutch government’s open geodata service: the Actueel_orthoHR layer of Beeldmateriaal Nederland, available under CC BY 4.0. The façades of the rebuilt landmarks were also compared against the panorama imagery of the City of Amsterdam.

Those photographs were used for measuring against. They are not in the game: they sit in a separate folder in the project that the engine skips, so they never reach the app.

The roofs and heights of the rebuilt buildings were measured against the 3D BAG, an open dataset by the 3D geoinformation group, Delft University of Technology.

The 3D BAG is available under Creative Commons Attribution 4.0 International (CC BY 4.0). That licence asks for attribution, and this is it.

The three-dimensional player character, with its animations for standing, walking, running, jumping and sitting, comes from the Universal Animation Library by Quaternius. The husky and the shiba inu walking through the city come from Ultimate Animated Animals by the same maker.

Both are released under CC0 1.0, public domain. Attribution is not required for that. It is here because it belongs here.

The game was made with the Godot Engine, which is freely available under the MIT licence. Inside the game Godot sits at the bottom of the list under Bronnen (Sources), and that entry prints the engine’s own licence text — including the third-party components inside Godot, each with its own licence, as those licences require.

Every source that is in the app also appears in the game itself, under Bronnen (Sources): OpenStreetMap, the 3D BAG, the two Quaternius packs and the Godot Engine. While you play, the OpenStreetMap credit also sits in the corner of the screen. Attribution that lives only on a website and not in the product is not attribution, and under the ODbL that is literally not enough.

One thing is not listed there, and that is not an oversight: the photographs from PDOK and from the city. They are not in the app, so they need no credit inside it. They are on this page because they were used.

The vehicles, the façades and the roofs, the businesses, the invented names and all the text in the game are original work.

The sound. There are 66 sound files in the game, and that is all of them: the engine loops, eleven kinds of engine in six states — idling, three stages of pulling and two of coasting. Those were not recorded either, and they did not come out of a library. They are computed by a script inside the project, from ignition pulses, resonances and noise: one bang per cylinder per cycle, pushed through the cavities of exhaust, block and intake, with a noise bed that moves with the bangs. They sit in the game as files rather than as a formula so that a real recording can take their place without a single line of code changing.

Every other sound is computed while you play: the impacts, the explosions, the gunshots, the swings, the coin, the tram bell, the horn and the barrel organ on the square. That tune is a formula.

All vehicles, businesses and people in the game are invented. Any resemblance to an existing brand or person is unintended.