10.4 · External Devices
External GPS
A sharper entrance fix from a Bluetooth GPS receiver.
Pair it: Confirm the receiver is feeding location before a trip.
Switch the receiver on and pair it in iOS Settings, Bluetooth: iOS pairs GPS receivers itself. Then in SpeleoMap, Settings → Devices, turn on GPS and tap Check. Outside, it shows EXTERNAL GPS and the accuracy when the receiver is feeding location.
Lock the entrance: Proof of where your registry coordinates came from.
Use the GPS lock as usual. When fixes come from the receiver, the card shows EXTERNAL GPS, and the locked entrance fix records it, so anyone reading the survey knows how it was taken.
Hike lines and pins: No setting needed on the trail.
They use the receiver too, the same way every iPhone app does.
Which receivers: Avoid buying one that won't work.
Any Bluetooth GPS receiver that works with iPhone apps through Location Services. Check that before you buy: some only work inside their maker's app.
Do you need one?: Whether a receiver is worth carrying.
A Pro iPhone's own averaged fix is usually within a few meters, which is plenty for a cave registry. A receiver tightens it further.
Mentioned in: 9.8 Devices · 1.4 Calibration