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geoid and ellispoid

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Philip Sargent
2025-02-13 15:42:13 +00:00
parent f1686578c8
commit 45fcc2d62e
2 changed files with 8 additions and 8 deletions
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5
handbook/survey/lasers.htm
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@@ -97,8 +97,11 @@ noted as possibly being dodgy, but we have no real indication of why.</p>
<p>This table shows the coordinates of the laser points in UTM using the WGS84
datum, which is the coordinate system we now use for the expo dataset (and
which the Austrian's kataster also now uses). If you want the original
coordinates, see the <i>*fix</i> commands in the file fixedpts/laser.svx
coordinates, see the <i>*fix</i> commands in the file <var>fixedpts/laser.svx</var>
in the Survex dataset.</p>
<p>[Just noticed in 2025: the altitudes in <var>loser/fixedpts/laser.svx</var> are not
te same as those in the table below. Current altitudes are 46.81m lower as we now measure altitude from
the geoid not the ellispoid; or <a href="https://support.virtual-surveyor.com/support/solutions/articles/1000261349-the-difference-between-ellipsoidal-geoid-and-orthometric-elevations-">possibly vice-versa</a>.]</p>
<table class="trad">
<tr><th>Code</th><th> Easting</th><th> Northing</th><th> Altitude</th><th>

11
piclinks/ssvypl.htm
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@@ -1,8 +1,6 @@
<html>
<head>
<title>
Surface Survey - Stellerweg area
</title>
<title>Surface Survey - Stellerweg area</title>
<link rel="stylesheet" type="text/css" href="/css/main2.css" />
</head>
<body>
@@ -12,9 +10,9 @@ Schwarzmooskogel in 1983, above the Stellerwegh&ouml;hle system.</p>
<p>This was the first attempt to find surface entrances corresponding to the large phreatic level
of the 'Dartford Tunnel' area in 115, and specifically to find the surface location of the very
string outward draft at the end of the Fuitility Series (Nutzlos) found by Chas and Phil Sargent.
strong outward draft at the end of the Fuitility Series (Nutzlos) found by Chas and Phil Sargent.
Phil had another look for these hoped-for entrances in 2018 and 2019, and learned that GPS altitudes are too poor
to be useful. We need to do more surface suyveying like this!
to be useful. We need to do more surface surveying like this!
<p class="caption">Photo &copy; Chas. Butcher, 1983. lookfutile.svx</p>
<!-- Photo 195, Photo-CD 6121 1651 2353 img 35 -->
@@ -33,6 +31,5 @@ to be useful. We need to do more surface suyveying like this!
</ul></li>
</ul></li>
<li><a href="../../index.htm">Back to CUCC Home page</a></li>
</ul>
</body>
</ul></body>
</html>