hsilvosa/safecast-radiation

Safecast Historical Radiation Measurements

Dataset description

This dataset contains the complete historical radiation-measurement snapshot published by Safecast. Safecast is a volunteer-driven citizen-science project created in 2011. Measurements are contributed by mobile and fixed devices and cover locations around the world.

The dataset supports environmental research, time-series analysis, mapping, sensor comparison, and studies of citizen-science data collection. Measurements should not be interpreted as official safety guidance or as a uniform spatial sample.

Data structure

Each row represents one measurement. The measurements configuration contains:

Field	Description
captured_at	Time recorded by the measuring device
latitude, longitude	WGS84 coordinates
value, unit	Reported measurement and its source unit
location_name	Optional location label
device_id	Safecast device identifier
md5sum	Source record checksum when supplied
height	Measurement height when supplied
surface	Surface description when supplied
radiation	Radiation metadata supplied by the source
uploaded_at	Time the record was uploaded
loader_id	Source loader identifier

The original units are retained. Values with different units must not be compared without an appropriate conversion and knowledge of the detector involved.

Processing

The official compressed CSV dump is read as a stream, assigned explicit Arrow types, divided into one-million-row shards, and stored as Zstandard-compressed Parquet. No API queries, interpolation, aggregation, unit conversion, or deduplication are applied. Provenance, schema, profile, quality, and checksum artifacts describe the exact snapshot.

Data quality and limitations

Safecast is crowdsourced observational data. Geographic and temporal coverage is uneven, devices and collection protocols can differ, and optional metadata is frequently absent. Coordinates indicate reported measurement locations, not complete area coverage. Users should account for repeated measurements, device effects, sampling density, and source units in downstream analysis.

The published snapshot retains source anomalies rather than silently deleting them. It contains 29,707 rows without a captured time, 4,365 rows without coordinates, 229 captured times before 1900, and 33,063 captured times after the snapshot date. These rows can be filtered using captured_at, latitude, and longitude when a downstream task requires plausible time and location values.

All rows use the train split. Spatial or temporal evaluation splits should be created downstream to avoid leakage.

Licence

Safecast publishes its measurement data under CC0 1.0. Attribution is not legally required, but acknowledging Safecast and its contributors is recommended.

Suggested attribution: Source: Safecast contributors; transformed to Parquet.