What would it look like if 42% of the buildings in my city were gone?

I'll be honest - the last few weeks have been rough. For me, for the world, for the people in Palestine and Israel. Way worse for them than what I'm going through. Obviously.

Thousands of people who were alive weeks ago are now dead. Including babies. And then came the news cycles about how those babies died and who lied about it. And then a hospital was attacked and even more people died. And then more TV news time spent talking about who did it but not about helping the people who survived it or who's families were shattered as a result. And the bombs have continued, they have not stopped.

War is horrible and uncontrollable. For me, a person living in California who has never even been near a gunfight, it's also pretty incomprehensible.

The photos and videos and news reports and fake news reports and unverified news reports just keep coming. I wish it would stop because war is terrible. For everybody. It's bad for journalists, it's bad for people who just want to live their one short life in the company of family and friends. It's more often than not bad for Jews. Right now it's unimaginably bad for the people being bombed in Gaza. It's bad for anybody who thinks it's paramount that we learn to live in peace with each other.

I read, days ago, that the UN thinks that 42% of the residential buildings in Gaza have been destroyed. What does that even mean?

I have no idea. I've never been to Gaza, I don't know how many buildings are there. I've seen pictures of what was there before and I've seen pictures of the destruction since bombs rained from the sky. It's horrifying.

But I do know a few American cities pretty well, the ones I've lived in at least. That would be Sacramento, New York, and San Francisco.

Since I use data visualization to better understand the world all the time, I figured I could try and use it to see what would it look like if 42% of the buildings in those cities were gone.

My reaction: Fuck.

Here's all the buildings in parts of those cities and what it looks like when just less than half of the buildings are removed.

Look, I'm not a government or international agency and I don't have information about which buildings are residential and which aren't.

Instead I just made an assumption that residential buildings are smaller than commerical or industrial ones so any building with a footprint smaller than 10,000 square meters is "residential" for my purposes.

It goes without saying, but I'll say it, that this is not what it would actually look like. It's a visualization, sanitized and normalized along the horror axis. But it helps me. I guess.

Ceasefire now!

Learn more about how I made the maps

I wrote a Makefile so that I could easily apply the process to three different cities but here's the methodology I used for each city.

1. First, I downloaded the building footprints from Microsoft.
2. Next, I used mapshaper to clip the GeoJSON to a much smaller size for each city. Sacramento for example:

   mapshaper-xl 15gb -i California.geojson -clip bbox=-121.573505,38.537022,-121.406479,38.622772 -o format=geojson sacramento-clipped.json

3. After that, I generated a new GeoJSON file that has a removed attribute set to true or false using a script. This variable determines if the building fades in and out or doesn't animate at all.

   import { promises as fs } from 'fs'
   import area from '@turf/area'
   import sacramento from './sacramento-clipped.json' assert { type: 'json' }
   const { features } = sacramento
   const percent = .42
   const areaThreshold = 10000
   const belowArea = features.filter(feature => {
       const a = area(feature)
       return a < areaThreshold
   })
   const l = belowArea.length * percent
   let aboveOrEqualAreaCount = 0
   const transformed = features.map((feature, i) => {
     const a = area(feature)
     feature.properties.removed = false
     if (a >= areaThreshold) {
       aboveOrEqualAreaCount += 1
     } else {
       let ii = i - aboveOrEqualAreaCount
       if (ii < l) {
         feature.properties.removed = true
       }
     }
     return feature
   })
   const featureCollection = { type: 'FeatureCollection', features: transformed }
   await fs.writeFile('sacramento.json', JSON.stringify(featureCollection))
   

4. Finally, I used tippecanoe to generate PMTiles which are super easy to host and use without third party services.

   tippecanoe -o sacramento.pmtiles sacramento.json