Christian Hollinger
@chollinger93.bsky.social
Principal SWE @ngrokHQ. Building skaldmaps.com. λ enjoyer and data wrangler. Shepherd wildlife for fun on a few acres in north Georgia. No replacement for displacement. https://chollinger.com/
On today's #blog: Why ZIP codes aren't great for #GIS: https://skaldmaps.com/blog/2026/07/zip-codes-are-a-bad-spatial-abstraction/
Today's #Map: #Birmingham, #Alabama 's pre-1960 housing share shows the city's industrial past. Highlighted: The wonderful Saw's BBQ in #Homewood, AL (made with https://skaldmaps.com)
In the spirit of #America250: While we don't have pre-1753 housing stock, here's pre 1960 housing share in #Philadelphia. Highlighted is 520 Chestnut St, also known as Independence Hall, where the Declaration of Independence and the Constitution of the United States were signed, built in 1753. 🇺🇸
Happy 250th birthday, America! 🇺🇸 #America250
SkaldMaps recently added new housing market and permit-based investment signals. 🎉 For instance, "New Build Value / Home Value" gives you the YtD permitted residential construction value per unit divided by median mortgaged owner home value...
Today's #Map: SkaldMap's urbanicity classification in #NYC, which is a composite score derived from tract density, place/city/metro context, urban area overlap, and HUD characteristics. Can you spot the airports? #urban #RealEstate
SkaldMaps.com tract data for serious deep dives just got an update: Tract and county views can use amenities, annual weather, and voting estimates! This used to be exclusive to the ZIP level. Here's a proximity map to the nearest #Dunkin in #Alabama - I spy a donut dessert.
Today's #Map: #Florida 's #Miami urban area is heavily constrained by protected land and the Miami-Dade Urban Development Boundary (made with https://skaldmaps.com)
#Chicago's urban sprawl has some interesting statistical anomalies - on the census tract level, you can see both the airport and the ~70,000 acres of nature preserve in Cook County, IL. Made with https://skaldmaps.com/
#Alaska has probably some of the most fun #GIS edge cases. Today's case: Barely any ZIP code coverage. Not a SkaldMaps.com bug - just a wild place.
SkaldMaps is now on SaaSHub! 👉 https://www.saashub.com/skaldmaps-alternatives
SkaldMaps now shows you a very neat little confidence indicator on how accurate the attribute you're viewing for a particular geography is: Find our how we do it on the brand new 🎉#blog 🎉: https://skaldmaps.com/blog/2026/06/building-confidence-in-geospatial-data/ #DataQuality #DataScience
Coming soon: SkaldMaps Data quality metrics and confidence on how reliable a given attribute is on a given geography. As you can imagine, ACS data on a tract level will be more precise than trying to map weather data to an entire county. #DataScience #DataEngineering #RealEstate
UX improvements @ https://SkaldMaps.com - cleaner navigation and a much improved rating flow just shipped. Check out the demo, where we quickly show the rating engine to find ZIPs around Alpharetta, GA with great retail and healthcare access. #RealEstate #LocationIntelligence
SkaldMaps now officially support tract and county level data @ https://skaldmaps.com! Check out the true suburban sprawl of Atlanta, GA, based on our classification for urbanicity, which is a custom composite score - available per tract, ZIP, or county. #RealEstate #Atlanta
I've released an update to SkaldMaps which improves the UI and fixes some data issues, based on early feedback from users: Filters, overlays, details, and more. Check it out! https://skaldmaps.com #RealEstate #PropertyResearch #DataEngineering
Hello world! I built a thing: skaldmaps.com SkaldMaps is a research, analysis, and rating platform for real estate investments, including primary home buyers (or renters). It lets you analyze, filter, and rank all US ZIP codes by a model you define yourself.
SkaldMaps - Every U.S. ZIP code, ranked by what you care about
Compare ownership costs, rent benchmarks, schools, weather, commute, and hundreds of other public data points across all 33,000 U.S. ZIP codes. Build your own ranking - for buying a home, helping a cl...
skaldmaps.com