Three
Counties Survey data and relationship to the surface Topography
Several members have been asking
about access to the survey data now that we have a PC in the Library area so
here goes with an article of a number of ways of looking at the Three Counties
surveys and also in relation to the surface topography.
I will try to keep this article as
non techy as possible as it is aimed at the not so computer literate of us.
Survex
Firstly you need to understand that
the survey data has all been processed using "Survex", a computer
program developed by Wookey. Survex is an open source
cave-surveying software package.
It is designed to be
portable and can be run on a variety of platforms, including Linux/Unix, Mac OS
X, and Microsoft Windows. It has been installed on the PC upstairs in the
Reading Room at the Farm.
The latest version of the
Easegill survey is also loaded onto the same PC.
Survex is very powerful cave survey software, and is actively
developing into a complete cave visualisation package. It has a sophisticated
but easy to use front end. https://survex.com/
You can download your version for the type of computer you have
from the website.
Once you have the program you will be able to view the survey
files of the Three Counties System. All sorts of files are located in the
depository maintained by Becka Lawson at:-
.
http://cave-registry.org.uk/svn/NorthernEngland/ThreeCountiesArea/survexdata/
Aven
Aven displays processed cave surveys in a window and allows you to
manipulate the view. The file needed is the Easegill-Pippikin.3d file from the
depository above.
Download this and save it somewhere you can find it again. The .3d
files will run in Aven.
Mouse Control
The best way to move the cave is with
the mouse. I suggest you try each of these out after reading this section to
get a feel for how they work.
If
you hold down the right button then the cave is dragged when you move the
mouse.
If
you hold down the left button, then the cave is rotated if you move left or
right, and zoomed if you move up and down.
If
you hold down Ctrl while dragging with the left mouse button, then the
cave rotates and tilts at the same time instead.
If
your mouse has a middle button then holding it down and moving the mouse up and
down tilts the cave. Moving the mouse left and right has no effect.
What about
Google Earth
The cave survey can also
be viewed in Goggle Earth using a kml file. KML is a file format used
to display geographic data in an Earth browser such as Google Earth.
The Survex data has been converted
into .kml or .kmz files that can be run in Google Earth so that you can see
where the caves fit in with the surface topography.
I have put the latest .kml files on
the Red Rose website at this link along with the latest easegill.3d file that
we have. I will try to keep this updated.
1
Install the free Google Earth tool on your computer
2
Double-click on any .kmz file to open it in Google Earth.
3
Right-click (or control-click) on the .kmz layer and select Save
As.
4
Use the Save As drop down menu to select .kml format.
5
http://www.rrcpc.org.uk/wordpress/survey-and-google-earth-files
It
will look like this once you run it in Aven
Part of
Lancaster Hole, Gale Garth and Cow Pot area imported into Google Earth
Andy Hall