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2001-08-15 20:29:27 +02:00

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Laser Points
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<h1>Geographical fixed points on Loser</h1>
<p>The coordinate system used by the Austrian Kataster is called the
Gau&szlig; + Kr&uuml;ger Landeskoordinatensystem, which is supposedly
identical to the widely used Universal Transverse Mercator system (Gau&szlig;
analysed the projection in 1822 and Kr&uuml;ger published formulae to
translate to/from Lat/Long in 1912). In our area, this is UTM zone 31. At
least, this was our belief, but we don't seem to be getting perfect agreement
between UTM/31 figures from GPS and the G&amp;K coordinates of fixed
points... This is probably because the bulk of Austria is in UTM zone 33.
Hmmmm.
<p>Within this system, there are a number of triangulation points surveyed
purely for the purpose of locating caves: these are the
Katastertriangulierungspunkte, or KT points. A point to watch when reading
the Austrian literature is that the numbers labelled X and Y are the
opposite way round from what seems normal to most people, ie. X is the
northing and Y is the easting. The X coordinate, when quoted in full, is
actually the distance in metres north of the equator, but usually the
leading two digits are omitted, to give the same number of digits in the two
coordinates. When the two extra digits are quoted, then the coordinates are
not the same length, which can cause confusion if you're used to British
National Grid references (where the east and west coordinates are run
together as if a single number).
<p>Within our area, a number of derivative points were surveyed (with a laser
rangefinder/theodolite) near to various caves. This work was done in two
sessions, in summer 1987 (with CUCC) and in 199x (with ArGe?). The points are
marked with spits in the rock, and originally with some form of flagging
tape. However, those which aren't right next to well-known caves are now
proving quite hard to find in the field, at least partly owing to some very
poor sketching of their locations.
<p>For these derived points, the main number is just a sequence number. The
ones which were derived via an intermediate derived point (rather than
directly from KT points) have a prefix indicating the point from which they
were derived. Hence, for example, point 7/9 on the 201 path near
Elchh&ouml;hle, was the ninth derived point, and was found by theodoliting
and rangefinding from point 7, on the Br&auml;uning Nase. This numbering
makes it easier, if one point is found to be in error, to work out which ones
were derived from it and will therefore also be wrong.
<p>As far as we are aware, all of these points which we have visited are
correct, with the exception of 7/11 on the col (ie. the most useful point,
nearest Top Camp), which seems to be out by an angular error of 25 or 26&deg;
from the Nase point. In the table, point 14/16 is also noted as possibly
being dodgy, but we have no real indication of why.
<table>
<tr><td>point</td><td>Y (east)</td><td>X (north)</td><td>Altitude</td><td>where ?</td></tr>
<tr><td>KT114-96</td><td>36670.37</td><td>(52)83317.43</td><td>1903.97</td><td>Hinterer Schwarzmooskogel Trig point</td></tr>
<tr><td>0</td><td>36386.56</td><td>(52)82804.16</td><td>1815.45</td><td>Hilfstandpunkt (hillock N of <a href="../../smkridge/161/top.htm">161</a>)</td></tr>
<tr><td>0/1</td><td>36093.56</td><td>(52)82337.43</td><td>1782.35</td><td>Between <a href="../../smkridge/156.htm">156</a> and <a href="../../smkridge/201.htm">201</a><br> cloth labelled "0/1" replaced with alloy tag "LASER 0/1" (1999)</td></tr>
<tr><td>0/2</td><td>36029.92</td><td>(52)82432.14</td><td>1750.06</td><td>Near</td></tr>
<tr><td>0/3</td><td>35866.51</td><td>(52)82424.03</td><td>1710.16</td><td>Near</td></tr>
<tr><td>0/4</td><td>35927.72</td><td>(52)82537.57</td><td>1687.45</td><td><a href="../../plateau/145.htm">Wolfh&ouml;hle</a></td></tr>
<tr><td>0/5</td><td>36005.96</td><td>(52)82782.82</td><td>1690.70</td><td>up gully and left from <a href="../../plateau/107.htm">107</a><br>
tatty cloth replaced with alloy tag "LASER 0/5" 1998</td></tr>
<tr><td>0/6</td><td>35873.09</td><td>(52)82944.29</td><td>1647.78</td><td>Near <a href="../../plateau/76.htm">76</a> - between the three entrances</td></tr>
<tr><td>0/7</td><td>35419.56</td><td>(52)82237.16</td><td>1769.77</td><td>Br&auml;uning Nase</td></tr>
<tr><td>7/8</td><td>36040.75</td><td>(52)81522.72</td><td>1732.39</td><td>Felskuppe im Bereich des Vd. Schwarzmooskogel (Wei&szlig;e Warze, The Nipple, Bunter's Bulge)</td></tr>
<tr><td>7/9</td><td>35395.41</td><td>(52)81044.60</td><td>1588.31</td><td>Elchh&ouml;hle <a href="../../noinfo/smkridge/31.htm">1623/31</a>, Punkt am Weg</td></tr>
<tr><td>7/10</td><td>35620.23</td><td>(52)81945.22</td><td>1629.97</td><td>Kratzer Valley below the col</td></tr>
<tr><td>7/11</td><td>35659.16</td><td>(52)82394.55</td><td>1682.67</td><td>Schwarzmoossattel (the col) - <i>we believe this is in error</i></td></tr>
<tr><td>8/12</td><td>35924.02</td><td>(52)81699.80</td><td>1725.04</td><td></td></tr>
<tr><td>8/13</td><td>36171.86</td><td>(52)81947.11</td><td>1775.14</td><td></td></tr>
<tr><td>8/14</td><td>36458.17</td><td>(52)81700.42</td><td>1689.48</td><td>Schwarzmooskogeleish&ouml;hle <a href="../../noinfo/smkridge/40.htm">1623/40a</a></td></tr>
<tr><td>14/15</td><td>36464.69</td><td>(52)81751.21</td><td>1686.66</td><td></td></tr>
<tr><td>14/16</td><td>36558.32</td><td>(52)81537.13</td><td>1660.39</td><td>(possibly dodgy ?)</td></tr>
</table>
<p>These fixed points are accessible in the Survex dataset at
<a href="../../data/fixedpts/laser.svx">FixedPts.Laser/svx</a>
<p><img src="../../../icons/roadwk.gif" align=bottom>A description of our own
surface surveys in the area is under construction, and should eventually
include details of how to find these laserfound points and other fixed
points. Currently, locations of caves in the kataster may be quoted as these
coordinates, or as Latitude/Longitude derived from the Austrian Alpine Club
(OAV) map sheet 15/1, which does not have a grid. Trying to get all these
locations into a single coordinate system is a priority, but will involve
quite a lot of unglamorous surface surveying, so don't hold your breath...
<p>In some Austrian literature, the easting quoted is in a system labelled
BMN. The Easting grid line +36000 (Gau&szlig; + Kr&uuml;ger, M31) is the
same as BMN 486000, and translation appears to be a matter of simple
addition or subtraction, though it may prove to be more complex than this
over a large enough area, as already indicated by GPS work...
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