Create procedurally generated city maps in the style of American grid-based cities.

More detailed documentation and instructions here.
Support the project on Patreon
Follow me on Twitter: @probabletrain
View the source: Github

What's New:

Using downloaded assets:

Feel free to use downloaded images and 3D models however you like! Credit is appreciated but not required.

I'd love to see what you make, send it to me on Twitter!


  • .png download
  • .png heightmap download
  • .svg download
  • .stl download
  • Several colour themes including Google Maps, Apple Maps, and hand-drawn styles
  • Pseudo-3D buildings
  • Open source

Basic Usage:

  • Click 'Generate' in the menu in the top right
  • Drag and scroll to pan and zoom
  • Open the 'Style' folder to access styling options - Switch to 'GoogleNoZoom' to see 3D buildings, or 'Google' to see buildings when zoomed in
  • You can turn 3D buildings on/off for any style with 'buildingModels'
  • When 'zoomBuildings' is enabled, buildings are only shown when zoomed in
  • Download a high-res image of what's on screen with the 'Download' button in the 'options' folder
  • Use 'imageScale' to control the resolution of the downloaded image - higher imageScale for higher resolution
  • Mac users and other users with high-DPI displays - Tick 'highDPI' under options to increase the resolution of the canvas


  • The size of the generated world depends on your zoom + pan when you click generate
  • The more zoomed in you are, the smaller the map and the faster it will generate
  • 3D buildings slow down pan+zoom, but not generation time. You can turn them on when you want them with the 'buildingModels' option under 'Style'

Advanced Usage:

Tensor Field

Cities are generated using  tensor field. If you open the 'Tensor Field' folder you'll be able to view and edit it. You can add and remove grid elements. Use the red squares to drag them to different positions. Under the folder corresponding to each element, you can change its size and decay. You can also change the angle of the fields.

Click 'setRecommended' in the tensor field folder to have the tool place 4 grids and one radial field in the scene. These have random parameters, so click multiple times until you find one you like

IMPORTANT: After editing the Tensor field, you need to open the 'Maps' folder to generate roads. The main 'generate' button above the tensor folder will randomise the tensor field.


Open the 'Maps' folder to start creating roads. You can click 'generateEverything' or step through the process manually.

  • Water - generate until you find a sea and river combination you like. Under the params folders, you can change the noise parameters to control how rough the shore and river bank are. The simplify tolerance controls how closely the road follows the waterline.
  • Roads - There are three road sizes: main, major, minor. Under each of the folders, you can click generate to create each class of roads individually. You can go back and edit the tensor field at any point in this process to create roads on different tensor fields. Experiment.
  • Buildings - click 'addBuildings' to fill the city with buildings. If you can't see them, the chosen style might not display buildings, or you might not be zoomed in enough. The 'Default' style, and 'GoogleNoZoom' styles both show buildings at all zoom levels. You can change the minimum building size, and the sidewalk size with 'shrinkSpacing'
  • Animation - Generation will be faster if you untick 'Animate', but note that this will swamp the UI thread so you won't be able to pan, zoom, or retry until generation has completed. Animation speed gives you a tradeoff between FPS and generation time.

Recommended Workflow

Here are the steps I usually take when I use the tool:

  • Water First - I open the Map/Water folder and click Generate until I’m happy with the water features.
  • Tensor Field Detail - Opening the Tensor folder reveals the tensor field. I addRadial a couple of times to add some roundabouts. I addGrid a few times and change their size, decay, and position to vary the grid structure.
  • Roads - I step through each of the Main, Major, Minor folders Generateing roads at each stage, moving to the next when I’m happy. Increase numParks under Map/Params if you want more parks.
  • Buildings - Buildings/AddBuildings

Source code: Github

Twitter: @probabletrain

Feel free to contact me with any questions, feature requests, or bug reports by email, Twitter, Github, or in the comments.

Check out the project board for known bugs/upcoming features.

Development log


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This is pretty fantastic! I was wondering if there was a way to spit the parameters out into the URL with each change, or some other method for the user to save/load a configuration.

If that was possible, people might be able to

  1. Come back to the exact configuration
  2. Share a map to allow others to tweak
  3. Create a "save state" of sorts allowing for Undo actions (i.e. 'navigate back')

Really awesome great stuff you have here!


Say, is it possible to put the number of inhabitants of the city in the generated map?

At least, does the number of people in the city affect the map?


Thank you so much for this! I've been needing something like this to help develop a campaign for tabletop Shadowrun! You have no idea how game changing this is for me!

<3 <3 <3




I play a crap ton of City Skylines. This has given me actually city layouts to build.



This is nice. Thank you.

(1 edit) (+2)

I love playing around with you tool and decided to recreate a city for your Tabletop game.

In the end I ran into a single problem: when filling in buildings a sizeable chunk of space wont get filled in. Is there a way to deactivate this behavior?

Also: How do I save my current map? After restarting Chrome everything was gone.

Also, I am using this tool to assist in drawing street networks in the OpenGeoFiction online fantasy mapping tool (using the Java Open Street Map Editor and image import plugins).

I'm having way too much fun with this.  How does one enable the ability to generate more than one river through the city?


One bug I noticed is that parks seem to clump together and are not spread out. A few possible features I think would improve the generator would be a way to better center the river perhaps, and control how much ocean is generated (sometimes, I've noticed, only a sliver of both is visible). I'm interested in possibly contributing to the project.

Hello! your work is remarkable I would like to propose the following functionality: I wish that it is possible to import 3d models, or then, in the parameters of the buildings, to be able to control the size (in length and width) of the buildings, in order that it is easy to replace them after export in stl by models that we created ourselves


This is rad! Thank you


This is really cool, it looks almost like real cities!