Data maps to translate information recorded in one code system to another code system are common in digital health. In the past these were used for data aggregation and national reporting where minor errors caused little impact. Today these maps are used invisibly behind the scenes when sharing clinical data. This is a data quality and safety bomb ready to blow. The International Standards Organization (ISO) have prepared to review their standard on map quality, a standard which when used can identify safety and quality issues in mapped data and assist in development of a pathway to improvement. The key determinants of map quality are discussed here and their impact on patient safety considered based upon real world experiences. Suggestions are included on the potential minimal requirements for any map used in a clinical environment, whether for use for interoperability or for other purposes. Alternatives to encourage improvement in map quality are also suggested.