Only Latitude and
Longitude are required. Every other numeric
column becomes a selectable metric. Known ones (RSRP, RSRQ, SINR, RSSI, CQI) come
with sensible thresholds; anything else gets thresholds derived from your data.
Tens of thousands of rows are fine — points are drawn straight to one canvas, and
thinned out when more land on screen than pixels can show.