How We Map PSNI Crime Data
Where the data comes from
Monthly mapped crime and anti-social behaviour records come from the Police Service of Northern Ireland (PSNI) through data.police.uk. We count published records whose anonymised locations fall within the area shown. These mapped counts are not complete official recorded-crime totals.
Wider council annual figures come from official PSNI statistics on the NISRA data portal. They use financial years and council boundaries, so they are presented separately from the monthly settlement series.
What a lookup actually measures
Postcode searches cover a one-mile radius around the selected location. Their combined incident count includes crime and anti-social behaviour, as labelled in the results.
Town reports use named NISRA Settlement Development Limits 2015. The map shows the actual boundary. The headline, monthly trend, crime categories and map use the same boundary and period. Crime totals exclude anti-social behaviour, which has its own headline and map selection.
These are fixed statistical settlement boundaries, not a claim about today’s built-up area, a postal address or a council boundary. The published Craigavon Urban Area includes Lurgan and Portadown, so those three reports share one clearly named reporting area. Metropolitan Newtownabbey and Warrenpoint/Burren are also named explicitly.
We retrieve enclosing areas from the Police API, then test each published location against the complete settlement boundary, including its separate parts and holes. Large requests can be divided into smaller areas; overlapping query edges and repeated record identifiers are handled to avoid counting a record twice.
Why we don't publish "crime rates per 1,000 people"
A defensible population rate needs a population count for exactly the same boundary and period as the crime numerator. We do not divide these mapped counts by an unrelated town or council population. Places differ in size, population, visitors and reporting behaviour, so raw counts are not a measure of individual risk or a safest-town ranking.
Known limitations we disclose
- Locations are approximate: published points are anonymised, often described as “on or near” a location. Several records can share a point. Moving a point for privacy can affect which side of a boundary it falls on.
- Coverage is incomplete: records without usable public locations cannot be included. Mapped counts can differ from official PSNI totals for other reasons too, including publication coverage, revisions and geography. We do not claim a fixed percentage of completeness.
- Publication is monthly: the latest available month is shown, rather than implying the figures describe today.
- Categories are those supplied by the Police API: violence and sexual offences is one combined category. Anti-social behaviour is separate from recorded crime.
- Different annual context: council figures cover a larger area and financial years. Changes in recording and the 2017/18 offence classification limit long-term comparisons.
How often it updates
Our system checks daily for new data and revisions. A town-report release requires all 13 consecutive months for every reporting boundary: 12 displayed months plus the matching month a year earlier. Invalid or incomplete responses do not become zeroes or partial totals.
If an update fails, the last verified complete release remains available with its reporting month. Source checks and data availability can lag during an outage. Automatic refreshes update the figures; they do not rebuild page layouts or overwrite the design.
Questions or corrections
If a figure or boundary appears wrong, contact us or call 028 7087 8077. Please include the town, reporting month and figure so we can check it against the source.
Contains public sector information from PSNI and NISRA licensed under the Open Government Licence v3.0. Settlement boundaries: NISRA / Land & Property Services, OSNI, 2015. Map data © OpenStreetMap contributors.