This metadata document describes the data contained in the "Argos GPS Processed Data" (Child Item 1) of this data release. This data release contains all data collected from 130 Argos and Argos-linked GPS satellite transmitters attached to Buff-breasted Sandpipers at breeding sites in Alaska, migratory stopovers in Texas, and wintering areas in Brazil, Argentina, and Uruguay, 2016-2018. The 130 deployed tags were comprised of 22 Argos Doppler PTTs (2 gram PTTs built by Microwave Telemetry) and 108 Argos-linked GPS PTTs (2 gram PinPoint tags built by Lotek). However, 14 Pinpoints never reported data, so they only appear in the deployment data records and not the location data files. One of the 94 functional PinPoint tags never reported GPS data, and 15 of the Pinpoint tags never obtained an Argos Doppler-derived location estimate. The raw (original) data from these tags were processed to accomplish three goals: 1) extract encoded GPS locations; 2) flag implausible locations; and 3) decode raw sensor data. Results of this data processing are presented in three Comma Separate Value (CSV) tables found in the "Argos Processed Data" (Child Item 1) of this data release: 1) the "GPS_filteredLocations" table contains one record for every GPS location which passed a manual plausibility assessment based on considerations of movement rate, seasonal range, and habitat; 2) the "diag_filteredLocations" table contains one record for every Argos location estimate collected, accompanied by a binary flag that denotes an algorithm's plausibility check (based on distance, turning angle, and rate thresholds). Each record in both the GPS and Argos filtered-location tables also includes a 'Tracking_Status' variable that denotes whether the location was collected from a live animal, a dead animal, or shed transmitter, 3) the "decodedSensor" table contains decoded sensor data (for only the Argos Doppler tags) of the transmitter's temperature and battery voltage. A fourth CSV table named "deploymentAttributes" is also included. It contains one record for each transmitter deployment, and contains information such as when the transmitter was attached to the animal, when tracking of a live animal ended, and a variety of variables describing the animal and transmitter. This table is identical to the "deploymentAttributes" table in the "Argos GPS Raw Data" (Child Item 2) of this data release.