The Difference is
in the Data
After reading over a million pages of zoning text, we've seen it all: codes without maps, maps without codes, codes that contradict their own maps, and codes that contradict themselves. Automated scraping tools built by AI agents can't resolve these problems — because the answers aren't found online. Learn about how our methods account for what machines miss.
There are no shortcuts when it comes to data accuracy. That's why our data is triple-vetted.
Every data point we collect benefits from:
1. Interpretation by Human Experts: We don’t rely on AI to read zoning codes. Our zoning and GIS analysts apply the National Zoning Atlas's methodology and use their judgment to translate unstructured texts and maps into a unified dataset. When in doubt, they pick up the phone and call planning staff.
2. Multi-Step Validation: Before publication, every entry is double-checked by at least three members of our team, whose experience includes law, geography, planning, and data science. Their expertise is the quality control layer that automated tools simply can't replicate.
3. Public Peer Review: Our Atlas will always remain freely available to the public. That transparency isn't just a public service; it's a form of peer review. Local experts catch things that even the best internal process might miss, and we’re glad to update as changes become available.
Don’t settle for zoning data slop.
Existing large-scale zoning datasets are riddled with errors: frankly, they’re slop.
Take this graphic on the left showing the “Land Allocation Breakdown” in Los Angeles published by a major zoning data provider.
Data visualization of Los Angeles zoning from a major zoning data provider.
Residential land in Los Angeles shown in purple on the National Zoning Atlas.
Anyone familiar with zoning can immediately spot the problems. For one, zoning districts allow multiple uses, so this pie chart just doesn’t compute. For another, the second largest city in the U.S. by population couldn’t be the second largest city if it only allowed people to live on 11.5% of its zoned land.
In reality, Los Angeles allows residential uses on nearly 90% of its zoned land, as shown in the map from the National Zoning Atlas that captures standardized calculations of residential, mixed with residential, and nonresidential uses. We know what and where those are because we put in the work. We didn’t sit back and ask AI to guess. We read the code, mapped the districts, called the jurisdiction, and sliced the data.
All of Land Use Labs’s data products are built from two fundamental components.
Our methodology is based on Zoning Districts and Zoning Slices. They are the reason our datasets are the only ones to capture how zoning actually works in the U.S.—use by use, lot by lot, structure by structure.
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To build our Zoning Districts, our team of trained analysts collects, cleans, and verifies as many as 200 zoning characteristics found in local codes using our standardized methodology. These zoning rules apply to properties within the boundaries of districts, which cover a defined area within (and sometimes outside) the city, town, county, or other type of jurisdiction that administers the zoning code.
Land Use Labs’s Zoning District boundaries are carefully digitized by trained geospatial analysts. Our team meticulously aligns borders and removes areas where zoning rules don’t apply, including state and federally protected land, water surfaces, and rights-of-way. All of this information is then validated by an experienced planning professional before being published on the National Zoning Atlas.
To uphold our commitment to data accuracy, all of our team members become zoning experts. They understand that common zoning rules like minimum lot sizes, parking requirements, height limits, setbacks, floor-to-area ratios, and lot coverage rules do not simply apply to districts. They apply to the uses, lots, and structures that are within districts.
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Comparing zoning rules across jurisdictions would be straightforward if districts never overlapped. But they do. Many zoning codes layer base districts and overlay districts on top of one another, so two or more sets of regulations can apply to the same piece of land at once. Ignoring that complexity doesn't simplify your analysis. It breaks it.
Zoning Slices are Land Use Labs’s solution to this problem. A Slice is the unique geometric combination of base and overlay districts that reflect how zoning rules actually operate. Our custom slice methodology overrides the regulations in the base districts with those from the overlay districts by flattening all possible layers. The output appears like a stained-glass mosaic, where each component, or “slice,” represents a distinct set of zoning rules that apply to the underlying land.
If you need zoning data to calculate area statistics, run comparative analyses, or conduct scenario planning, Zoning Slices are what you're looking for.
Long live accessible zoning for everyone.
By licensing our data, you support the National Zoning Atlas.