Mike, KD2KOG  has made an updated YouTube video showing how to receive APRS data using SDRconnect and MultiPSK.

Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time digital communications of information of immediate value in the local area. Data can include object Global Positioning System (GPS) coordinates, non-directional beacon, weather station telemetry, text messages, announcements, queries, and other telemetry.