CUCC Expo Surveying Handbook

Geographical fixed points on Loser

The coordinate system used by the Austrian Kataster is called the Gauß + Krüger Landeskoordinatensystem, which is supposedly identical to the widely used Universal Transverse Mercator system (Gauß analysed the projection in 1822 and Krüger 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&K coordinates of fixed points... This is probably because the bulk of Austria is in UTM zone 33. Hmmmm.

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).

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.

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 Elchhöhle, was the ninth derived point, and was found by theodoliting and rangefinding from point 7, on the Bräuning 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.

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° 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.

These fixed points are accessible in the Survex dataset at fixedpts/laser.svx.

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...

In some Austrian literature, the easting quoted is in a system labelled BMN. The Easting grid line +36000 (Gauß + Krüger, 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...

• Expedition Handbook:
  • Expo Handbook Introduction
  • Surveying:
    • Surveying Overview and index of topics
    • What is a cave survey?
    • Why am I doing this?
    • Methods: underground
    • Pitfalls to avoid, hints'n'tips to make life easier
    • Methods: surface
    • Base Camp: getting it in to the computer
    • Base Camp: drawing it up, writing the description
  • Prospecting guide
  • Rescue guide
  • Rigging guide
  • Photography guide
• Index to info/topics pages
• Full Index to area 1623
  • Area/subarea descriptions
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