Returns one contact data record by its own ID (not the contact ID). To read a contact's record by contact ID, use GET /contacts/{id}/contactData. The location fields (geoIp4, geoCountry2, geo_country, geoState, geoCity, geoZip, geoLat, geoLon, geoTz, geoTzOffset, geoTstamp) are filled by a MaxMind GeoIP lookup of an IP address recorded for the contact, for example when the contact subscribes, opens or clicks a tracked email, or is added through the v1 API with an ip4 value; contact enrichment can also fill the city, state, country, country code and zip when they are blank, and sets geoTstamp when it does. The gacampaign*, ga_first_visit, ga_times_visited, fb_id, fb_name and tw_id fields are legacy columns that the application no longer writes. Values come back as strings; tstamp, geoTstamp and ga_first_visit are ISO 8601 dates or null. No permission beyond API access is checked. Returns 404 if no record has this ID.