diff --git a/handbook/survey/newsurvex.html b/handbook/survey/newsurvex.html index 73d50d7fc..8a4941060 100644 --- a/handbook/survey/newsurvex.html +++ b/handbook/survey/newsurvex.html @@ -75,7 +75,7 @@ This page outlines step 3 of the survey production process. Each step is documen <p>The (strongly) recommended procedure is to take a specific GPS measurement at a well-defined point and to write down the location on your prospecting survey notes. Then for a new discovery it will be copied onto the New Cave data sheet. <p>Note that we record the location in degrees and decimals of degrees: <code>47.69055 13.80841</code> and the altitude is in metres. - <p>The altitude is not nearly as vital as the lat/long numbers. GPS altitudes are still pretty bad, and even the new Galileo system won't promise anything better than ± 0.4m in 2030. (If you take the altitude from a track while moving the altitude can easily be 15m wrong.) + <p>The altitude is almost useless: we get better altitudes by using the lat/long numbers together with a laser scan of the plateau topography. GPS altitudes will continue to be pretty bad, and even the new Galileo system won't promise anything better than ± 0.4m in 2030. (If you take the altitude from a track while moving the altitude can easily be 15m wrong.) <p>See <a href="#location">the bottom of this page</a> for how the location information is typed in.