How to Use LA County Parcel Data for Site Analysis (Without GIS)

If you need a building-age map, a land-use map or a lot-size map of a Los Angeles block, the data already exists and it is free. The Los Angeles County Assessor's parcel layer, published on LA County eGIS, carries the use, the year built, the number of units and the building floor area of every parcel in the county. As of October 2026 it holds 2,433,059 parcels, of which 2,203,149 (90.6%) have a year built.

Unlike New York's MapPLUTO, it covers the whole county — the City of Los Angeles, the other 87 cities and the unincorporated areas — in one schema. What it does not carry is zoning; that is each city's own data (trap 5).

This page is written from the inside: we use this layer in production to draw the Building age, Building use and Plot size panels for Los Angeles on sitedia, and the traps below are ones we hit.

The fields that matter

The layer has about ninety columns. For site analysis these are the ones you will actually use.

The broad use types, with how many parcels carry each one countywide:

Residential is 89% of the parcels — and the number is inflated by condominium units, each of which is its own parcel. Irrigated Farm is mostly Desert in UseDescription (48,213 parcels): undeveloped land in the north of the county, not farms in the city.

Getting the data without GIS software

The layer is published as an ArcGIS map service, which answers plain HTTP requests. The endpoint is:

https://cache.gis.lacounty.gov/cache/rest/services/LACounty_Cache/LACounty_Parcel/MapServer/0/query

Ask it for the parcels inside a bounding box, and only for the fields you need:

?where=1=1
&geometry=-118.26,34.04,-118.24,34.055
&geometryType=esriGeometryEnvelope
&inSR=4326
&spatialRel=esriSpatialRelIntersects
&outFields=AIN,UseDescription,YearBuilt1,Units1,SQFTmain1
&returnGeometry=true
&outSR=4326
&orderByFields=OBJECTID
&f=geojson

That returns GeoJSON — parcel polygons with the fields attached, in latitude and longitude. Two useful variants:

• Add returnCountOnly=true to ask how many parcels are in the box before downloading any. The box above holds 6,300.
• Use where for filters. Because the year is text, compare it as text: YearBuilt1 > '1700' AND YearBuilt1 < '1940' gives you the pre-war fabric of a neighbourhood.

Use this GIS service rather than the Assessor's property search portal. The county's eGIS terms allow reuse, including commercial use; the portal's own terms limit it to personal use.

Five traps that cost you data

1. You only get 2,000 parcels per request

The service stops at 2,000 records and sets exceededTransferLimit when there is more. This service sets the flag both at the top level of the GeoJSON and inside properties; other Esri services set it in only one of the two, so check both. Page with resultOffset and orderByFields=OBJECTID until the flag is gone. The 6,300-parcel box above takes four pages.

2. Condominiums are stacks of identical parcels

Every condominium unit is its own parcel, and every unit parcel has the same polygon — the building's lot, repeated once per unit. In an 800 m square around Pershing Square we pulled 2,510 parcels; 2,202 of them sat in 24 stacks, and the tallest stack, 400 S Broadway, was 452 parcels deep. Most stacked parcels carry ParcelTypeCode = 1 (2,003 of those 2,202; 351,956 countywide), but not all — group by geometry, not by the code.

Left alone, a stack breaks two things. A table of parcels lists one row per unit — that block alone gave hundreds of rows. And a join from building to parcel lands on whichever parcel comes first, which is often the common-area parcel with no address and no floor area. Group parcels with identical geometry into one lot: add the units, floor areas and values, take the most common year, and strip the unit number from the address.

3. The year is text, and there are five of them

YearBuilt1…YearBuilt5 describe up to five buildings on one parcel, stored as text. Unknown is either empty (221,094 parcels have no YearBuilt1) or the string 0000 (8,816). For an age map, read all five, decide what a parcel's "year" is — we use the earliest — and convert to a number before comparing.

4. Assessed value is not market value

California assesses property under Proposition 13: the value is set when a property changes hands or is built, then rises by at most 2% a year. Two identical houses can carry very different values because one sold in 1985 and the other in 2024 — Roll_LandBaseYear and Roll_ImpBaseYear tell you which. Read the values as tax basis, not as a price map.

5. Zoning is not in it

The parcel layer has no zoning. Each of the county's 88 cities writes its own; for the City of Los Angeles it is City Planning's zoning layer, the data behind ZIMAS. Even then, a zone string such as C2-2D-O or [HB5-SH1-5][CX3-FA][CPIO] does not give a maximum FAR by itself — height districts, D and Q conditions and community plan footnotes all change it. Check ZIMAS for the parcel before quoting a number.

What coverage actually looks like

Once the traps are handled, coverage in the City of Los Angeles is high. Measured on our own database inside half-mile circles, share of buildings with a year built and with a use:

The shortcut

If what you want is the drawing rather than the dataset, sitedia runs this pipeline for any site in the City of Los Angeles: building age, building use and plot size panels — plus footprints, heights, green space, transit, terrain and an aerial — as SVG, PNG, DXF or 3D. The parcel Details table adds City Planning zoning and a floor count estimated from LARIAC building heights, with condominium stacks already merged.

The full list of datasets and their measured coverage is on the data sources page.

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