slv.measurements.mobile.gps.GPS_NUMERIC

slv.measurements.mobile.gps.GPS_NUMERIC = ('Latitude_deg', 'Longitude_deg', 'Altitude_msl', 'Speed_m_s', 'Course_deg', 'N_Sat', 'Fix_Quality', 'QAQC_Flag', 'Battery_Voltage_V', 'Logger_T_C', 'Ambient_T_C', 'Ambient_RH_pct')

GPS columns forced to float64 on read. A year read on its own can hand back an all-NA column (Speed_m_s / Course_deg in the GPGGA-only years) as Arrow strings, which breaks the per-minute medians in slv.measurements.mobile.location.