You’re right, we don’t have one up yet. We did a few implementations of various government plans over the years (the Japan-funded COMTRANS being the most prominent) and I’ve invited a professional urban designer who works with the government to examine applications and limitations- so a more professional eval than just us saying “here’s a thing!”

Might write it all up as a paper if we have time.

The readme files in the repo have screenshots. Tried linking them here, but the URLs are massive, so let me link the docs -

1) Methodology: https://github.com/team-watchdog/colombo-skylines/wiki/Intro...

2) Main readme: https://github.com/team-watchdog/colombo-skylines

I'm reminded of Tom Stoppard's Arcadia, and the child genius Thomasina . . . "If you could stop every atom in its position and direction, and if your mind could comprehend all the actions thus suspended, then if you were really, really good at algebra . . ."

You would make Heisenberg roll in his grave!

Every tornado-generating butterfly would be out of a job, for sure

Sadly, the height maps and the OSM road imports were quite borked, so I just ended up doing all the roads by hand with the maps on a second monitor. Some screenshots of the process here: https://github.com/team-watchdog/colombo-skylines/wiki/Intro...

Sadly, that happens. We use image overlay and exports off ESPG 4326 and tweaked the hell out of the coords until it worked. Even then there are still issues - which is why we're about 100m shorter than the real city. The overlays match perfectly, but in reality distances are always a few meters off across a large stretch. OSM imports broke completely, so I just ended up doing all the roads by hand with the maps on a second monitor.

There's always a point where you look at the automated solution and think "Okay but... how long would it take to just to do manually?"

I enjoyed your comprehensive write-up. I really like how you didn't get too lost in the details when the technical limitations cropped up and kept the focus on the interactivity and public awareness. Very fun project :)

Thanks!

Methodology here: https://github.com/team-watchdog/colombo-skylines/wiki/Intro...

We've also tweaked many of the assumptions (traffic flow, citizen lifecycles etc) https://github.com/team-watchdog/colombo-skylines/wiki/mod-c... to get "somewhere in the vicinity" of how people actually behave - nursery school at 6 years old, high school after, then a job, maybe college, then employment and retirement at 65.

In some of the work that I was involved in years back we were using CDR (call detail records) to estimate human mobility. See: https://medium.com/@yudhanjaya/how-people-come-to-nallur-7d3...

We're certainly not that accurate, as the broader you go with simulation, the less deep you can get to. But as a teaching tool to help people think about the instersection of complex systems, it's decent.

If I had more time I'd spent it making a new asset pack so those houses look more Sri Lankan.

Realistically I don't think the UDA (Urban Development Authority) will use this, BUT we have had calls with them where they asked to see a demo and seemed massively excited at the prospect of being able to visualize changes in the character of the city (in fact they wanted to know if we could build municipal buildings if they gave us the maps). University students who eventually become GIS folks seem more like the audience that will actually end up running and tweaking this.

I had a similar notion, as I prior worked with a large southern California municipality that was into "smart city" things as a solutions architect, and they would have loved for something like this for the same reasons you stated, particularly visual changes or features, adjusting pedestrian/bike/car traffic flows, points of interest, etc.

I would love to know how large of a city would be possible to "import" and run with enough of a like data set. I would imagine it would give any GIS nerd a boner if they could do so themselves.

Even remotely close I would consider a feat, so bravo to the team that did this!

Thanks! You may want to read the methodology - most of the imports broke and it ended up being a lot of manual work: https://github.com/team-watchdog/colombo-skylines/wiki/Intro...

As for limits, when modded to the hilt, Skylines will give you:

298.6 sq km maximum area

1,048,576 maximum citizens

49,152 maximum individual buildings

65,636 maximum vehicles in motion

65,636 maximum parked vehicles

256 maximum transport lines (bus routes, train routes)

That will no doubt change the nature of the city you can set up - you could do a large city very sparsely, or a smaller area in greater detail.

So two people (myself and Nimesha) working for about four months straight, I think. Mostly eight to ten hour days. Three academics helping us find data for when public sources ran dry (especially flow along the corridors) - see the workflow at https://github.com/team-watchdog/colombo-skylines/wiki/Intro...

I think at some point I will, but this is a task that takes multiple overlapping fields of expertise - from simulations to 3D rendering. I'll teach myself over time. I build little procedural generation experiments for fun that make their way into my books. But this is one of those dreams that will take me a couple of years to get to the level where I'm competent enough to go for it.

Is it necessary to work in 3D initially? You can make the problem a lot easier when working in 2D.

Goal here was to build a visualization and communication tool; 3D is an essential component of that. For 2D, land use maps already exist.

Not even remotely close. If you have millions of dollars and lots of talented programmers, I can build an engine from scratch. We do not live in an ideal world - public policy is about the art of the possible, and $19.99 (cost of Skylines in Sri Lanka) is a massive improvement from the $8000 a year fee for CUBE or OpenPaths. I do want to build a sim someday, but I estimate the learning of it will take me a few years to complete. Right now I'm at the stage of writing basic galaxy generator toys like https://github.com/yudhanjaya/GalaxyGen

This is super impressive! I'd agree the open-source tooling isn't there yet, but it's coming in a few places. I started a 3D street visualizer but it's only at the scope of a few blocks at a time, not as large as a city area although we'd like to get there someday: https://github.com/3dstreet/3dstreet/

There's also https://github.com/a-b-street/abstreet for larger area simulation but with less visual fidelity

Very cool, great to see progress in this!