A new version of Survex, an open source cave-surveying software package, was released last week.

The new version, 1.2.18, adds support for displaying terrain data, improves Aven?s handling of the log from processing survey data, plus an assortment of other fixes and improvements.

Developed by cavers Olly Betts and Wookey, Survex is capable of processing cave survey data from extremely complex caves very quickly. It is licensed under the GPL and is can be run on a variety of platforms such as Windows, Mac and Linux.

Survex is used by many cave survey projects around the world, including the Ogof Draenen survey, the Easegill resurvey project, the Ogof Ffynnon Ddu survey, the OUCC Picos expeditions, and the Hong Meigui China expeditions.

For more information on the update, including the entire change log, or to grab yourself a copy, visit the Survex website:

http://survex.com/

Some more releases over the summer have added another notable feature: automatic magnetic declination calculation. From 1.2.20 you can use *calibrate auto to get the declination from a geophysical model.

This dramatically improved our Austria dataset which was started in the early 1990's when the offset was approx zero so we got used to not caring about it much. It has since grown to the best part of 3 degrees and was causing errors of up to 20m between caves by rotating newer data around each cave's entrance.

It occurs to me that a hidden Earth talk on 'new stuff in Survex over the last 10 years' would be a good idea, but too late for this year.

wookey said:

It occurs to me that a hidden Earth talk on 'new stuff in Survex over the last 10 years' would be a good idea, but too late for this year.

Click to expand...

But could be part of Eurospeleo next year... 

Indeed. Put me down for that.

I think I'll offer a talk on 'Cavers and Climate Change' too.

rhychydwr1 said:

...The new version, 1.2.18, adds support for displaying terrain data...

Click to expand...

Is there any guidance documentation anywhere to show show to include this? I have tried a number of methods but keep getting the error message "No coordinate system specified in survey data".

wookey said:

...From 1.2.20 you can use *calibrate auto to get the declination from a geophysical model...

Click to expand...

Again, i'm struggling to get this to implement, nor find any guidance documentation online. Typing "*calibrate auto" doesn't seem to work....

Or maybe i'll learn it all at the eagerly awaited lecture at EuroSpeleo: 
http://eurospeleo.uk/presentations/session.php?id=74

btw.. you were right and i should have been clicking 'surface shots' to get the surface to display.  However I sure I can be forgiven for thinking that the terrain button would do the same thing.

Rob,

Take a look at the *CS survex command, this according to the docs defines the coordinate reference system for the survey (according to the manual). The coordinate system is then encoded in the .3d model file header, (not that I have seen one that has this in, so it would be useful for me to see one).

Your surveys are in OSGB as is the BIL file I sent you so I imagine

*CS EPSG:27700

or

*CS OSGB:SK

in your .svx files would be what you need, and then you would need to recreate the model files. (EPSG:27700 and OSGB are the same thing)

your coordinates include the square letters part of the GR so I am not sure why the SK is needed, unless it assumes use of partial coordinates?


**** warning : I've only played with .3d files so may be completely wrong ****

aardgoose said:

*CS OSGB:SK

in your .svx files would be what you need, and then you would need to recreate the model files. (EPSG:27700 and OSGB are the same thing)

your coordinates include the square letters part of the GR so I am not sure why the SK is needed, unless it assumes use of partial coordinates?

Click to expand...

On the assumption it is the same as Therion, the SK is the major grid square referred to on OS map references. This makes OSGB:SK a subset of EPSG:27700 so the whole grid reference does not need to be used, which in the end is easier for the end user.

Generally these sort of questions will be answered far quicker by asking on the survex.com mailing list, which is also archived therefore becoming a useful resource

Thanks,

I know SK is the OSGB square.  The surveys Rob is working with use full numeric OSGB grid references, therefore the SK is redundant, The survex manual gives the impression that the square letters are necessary if using the OSGB: setting, and doesn't specify what happens if you are using full numeric references, which is what I was alluding to (EPSG:27700 is probably the safe answer).

I think it is a mistake to encourage the use of grid letters anyway, what happens when you cross square boundaries?

aardgoose said:

I think it is a mistake to encourage the use of grid letters anyway, what happens when you cross square boundaries?

Click to expand...

Not sure how survex fully handles it, but usually the same as Therion. In Therion you can set one output and many different input grids. Basic rule of inputting data is input it in the same format as it was originally recorded, so if recorded as an SK grid, that is how the data should be inputted.