The data contains some points outside Helsinki. There are some unaddressed parking violations in the table-form dataset; these are not present in the geospatial dataset.
The coordinate system of the dataset is ETRS-GK25 (EPSG:3879).
The spatial dataset is geocoded with the QGIS Digitransit Geocoding add-on. The default settings have been used for geocoding, except “Number of locations to be searched (may affect the accuracy of results)” ("Haettavien sijaintien määrä (voi vaikuttaa tulosten tarkkuuteen)" ) has been selected for the highest and most accurate possible value of 40. In the add-on setting “Address field names as a list separated by commas” ("Osoitekenttien nimet pilkuin eroteltuna listana"), the CSV file fields are used: Address (Osoite), Municipality (Kunta), District (Kaupunginosa), Borough_SV (Kaupunginosa_sv).
More information about the add-on: https://github.com/GispoCoding/QGISDigitransitGeocoding