diff --git a/handbook/survey/gps.htm b/handbook/survey/gps.htm index f77a4b857..d99a6d1e0 100644 --- a/handbook/survey/gps.htm +++ b/handbook/survey/gps.htm @@ -83,7 +83,7 @@ or a cairn, for example - we don't use paint any more) and place the GPS on the point. Don't build a cairn, they don't last for decades and we have survey stations that provide permanent locations. Give the GPS device a minute to get a fairly good fix (the first figure reported may be quite a way out is you have been moving). Then mark -the point as a "waypoint" in OSMand. + the point as a "waypoint" in OSMand AND, without moving the phone, take a screenshot of the GPStest screen (see below) showing the lat./long., the time and the various accuracy metrics.

Camera locations

@@ -91,7 +91,7 @@ the point as a "waypoint" in OSMand.
Camera photo locations are not
on the track!
-

Your camera will use the same location settings as the rest of your phone, but sometimes with a bit of a delay. We have lots of examples of geo-located photos where the recorded location is alctually the location of the previous photo because someone has taken a quick photo but the phone hasn't had time after waking up to get a location, so it uses the previous one! And doesn't tell you!! +

Your camera will use the same location settings as the rest of your phone, but sometimes with a bit of a delay. We have lots of examples of geo-located photos where the recorded location is actually the location of the previous photo because someone has taken a quick photo but the phone hasn't had time after waking up to get a location, so it uses the previous one! And doesn't tell you!!

So when taking a photo of an entrance, always take one photo; delete it, and take another. This will give your phone a chance to get synchronised properly. @@ -111,7 +111,7 @@ track log, then record another waypoint at the same place just before you leave so it's clear to someone examining the track log when you actually left.

-

Averaging used to be very important, but today (2026) we have so many GNSS satellites in the sky that ionospheric effects are the significant error. These change slowly over 5 hours or so, so avergaing for a minute or and hour does nothing useful. You would need to average over several days. The solution for a fast fix is to use RTK. +

Averaging used to be very important, but today (2026) we have so many GNSS satellites in the sky that ionospheric effects are the significant error. These change slowly over 5 hours or so, so averaging for a minute or an hour does nothing useful. You would need to average over several days. The solution for a fast fix is to use RTK.

While the GPS is averaging your location, you can do something useful (like rigging the cave, doing a surface survey from the GPS point to the