Blog
Guides for working with bulk property data
How-tos for people who work with property records by the million: loading and splitting big files, what each column means, building lists, estimating costs and keeping a dataset current.
- Planning a Whole-State Property Export on a Daily AllowanceHow many days a full state takes on each plan, how to split it into counties and ZIPs that fit each day, and how to resume and combine the files.9 min read
- How to Load a Statewide Property File Into PostgreSQLStaging table, COPY, typed DDL for every export column, the three indexes worth adding, and a partitioned layout for monthly snapshots.12 min read
- Filtering a Bulk Property File With DuckDBQuery a statewide property CSV in place by equity, property type, owner type and value with DuckDB: typed views, filters, Parquet and exports.10 min read
- Finding Portfolio Owners in a Bulk Property FileGroup properties by normalised owner name and mailing address, link LLCs that share an office, and handle trusts and estates, with SQL and pandas.10 min read
- Joining Property Records to Your Own Data by APN and County FIPSRepair county FIPS codes, normalise APN formats, check match rates county by county and fall back to address matching for the rest.10 min read
- Mapping Property Records by County and ZIP in QGIS or kepler.glAggregate a property export by county or ZIP, join it to Census boundary files, build choropleths in QGIS or kepler.gl, and geocode for points.11 min read
- How to Open a 5-Million-Row Property CSVExcel stops at 1,048,576 rows and Google Sheets at 10 million cells. How to split a large property CSV, or load it into pandas, DuckDB or a database instead.10 min read
- Property Data Field Dictionary: What Each Column MeansEvery column in a property export explained: owner vs mailing address, APN and county, estimated value, equity, DTV, open liens and distress columns.9 min read
- How to Build a County-Wide Mailing List From a Property ExportTurn a county property export into a direct-mail list: absentee vs owner-occupied, deduplicating multi-property owners, address cleanup, CASS and NCOA.9 min read
- Flat-Rate vs Per-Record Property Data Pricing: What a Project Really CostsCompare flat-rate and per-record property data pricing using record counts, refresh frequency, daily allowances and effective cost per 1,000 records.8 min read
- How Often Property Records Change, and How to Keep a Dataset FreshWhich property record fields change and why, how to diff two monthly exports by property ID, and a routine for keeping a property dataset current.10 min read