Author Topic: How to survey 101  (Read 14105 times)

Offline Peter Burgess

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Re: How to survey 101
« Reply #25 on: March 30, 2007, 11:10:29 am »
Don't forget that local gravitational anomalies may affect your clino.  ;) In particular, if your surveying helpers are extremely obese.  ;D

darkplaces

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Re: How to survey 101
« Reply #26 on: March 30, 2007, 11:16:22 am »
Oh gawd :( now its getting all complicated glad I currently don't feel the need to survey caves  :o just nice big straight line level mines hmmmm scrummy. Were aiming for SMCC Box type surveys but with loads of detail like 'really old fag packet here'... Its a bit of fun and might produce something useful.

Offline graham

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Re: How to survey 101
« Reply #27 on: March 30, 2007, 11:23:15 am »
Don't forget that local gravitational anomalies may affect your clino.  ;) In particular, if your surveying helpers are extremely obese.  ;D


Har har very funny. The fact of the matter is that a combination of compass error and mag variation can add up to about 12 degrees. That is clearly not acceptable in a situation where instruments can be read with a precision of 1/2 a degree.
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Offline Peter Burgess

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Re: How to survey 101
« Reply #28 on: March 30, 2007, 11:30:10 am »
Check that steel-framed spectacles are not affecting your compass bearings. This one is a serious comment!

Walrus

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Re: How to survey 101
« Reply #29 on: March 30, 2007, 11:32:50 am »
I downloaded survex last night and started playing with it.
A very simple and nice program, but the example posted above contains errors so this may be why there is confusion with the program, it does not build a .3d file.
But remove all but the data and it works ok.
Also you have to RIGHTclick the .svx filke and select 'process' to build the survey.

But... that implies I have to read some instructions   :blink:

I'm also going to have a play with a CAD application I've got (TotalCAD - comes free with cornflakes) as you can specify survey type angles & distances and get it to plot them using the GUI. Not looked at 3D versions yet.

Offline axbridgecaver

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Re: How to survey 101
« Reply #30 on: March 30, 2007, 12:11:10 pm »
Hi Darkplaces

I can come along to your site with the ACG surveying gear (compas, clino and tape) and give you and your friends a teach in on surveying. I have created an excel spreadsheet you just type the data in and out comes the plotting co-ordinates.

Then the difficult bit - I always hand plot the survey - I think the computer generated surveys are poor and a much better looking survey can be achieved using this method. Just my view. It does take time to hand plot and a large drawing board. I then scan the plot and electronically trace the survey then all the information and detail can be added.

PM if you wish me to come along.

darkplaces

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Re: How to survey 101
« Reply #31 on: March 30, 2007, 12:43:58 pm »
Hi Darkplaces
I can come along to your site with the ACG surveying gear (compas, clino and tape) and give you and your friends a teach in on surveying.
PM if you wish me to come along.
Ahhh thats very kind. I shall have to consort with my team mates. Are you free weekday evenings from 19:30hrs?

Offline paul

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Re: How to survey 101
« Reply #32 on: March 30, 2007, 01:00:31 pm »
Check that steel-framed spectacles are not affecting your compass bearings. This one is a serious comment!


And your helmet-mounted light - espcially LED types with electronics...
I'm not a complete idiot: some parts are missing!

Walrus

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Re: How to survey 101
« Reply #33 on: March 30, 2007, 01:10:56 pm »
Check that steel-framed spectacles are not affecting your compass bearings. This one is a serious comment!


And your helmet-mounted light - espcially LED types with electronics...

So if surveying I'd be better off using something like an FX5 (no fancy electronics)?

Offline menacer

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Re: How to survey 101
« Reply #34 on: March 30, 2007, 01:12:30 pm »

I tried this application on two XP machines; one wouldn't run (kept getting a DOS error) and the other ran but wouldn't read the supplied test data. I'll acquire a copy of Visio and try DP's method!

Sorry walrus, got home and just tried it, try the same using this

*begin box

0 1 3.8 225 0
1 2 5.4 256 0
2 3 12 312 0
3 4 6.2 360 0
*end box
Chaos, panic, and disorder - my work here is done.

Offline paul

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Re: How to survey 101
« Reply #35 on: March 30, 2007, 01:32:44 pm »
Oh gawd :( now its getting all complicated glad I currently don't feel the need to survey caves  :o just nice big straight line level mines hmmmm scrummy. Were aiming for SMCC Box type surveys but with loads of detail like 'really old fag packet here'... Its a bit of fun and might produce something useful.

Have a look at http://cucc.survex.com/expo/handbook/survey/what.htm for a bit more general information on cave surveying.
I'm not a complete idiot: some parts are missing!

Dep

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Re: How to survey 101
« Reply #36 on: March 30, 2007, 01:33:24 pm »
Check that steel-framed spectacles are not affecting your compass bearings. This one is a serious comment!


And your helmet-mounted light - espcially LED types with electronics...

So if surveying I'd be better off using something like an FX5 (no fancy electronics)?


Yess indeed, whilst helping Peter once I had about a degree of variation in backsight readings depending on whether or not I had my helmet on.

Offline paul

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Re: How to survey 101
« Reply #37 on: March 30, 2007, 01:35:16 pm »
Check that steel-framed spectacles are not affecting your compass bearings. This one is a serious comment!


And your helmet-mounted light - espcially LED types with electronics...

So if surveying I'd be better off using something like an FX5 (no fancy electronics)?

No use a brass carbide stinky! :)

The thing to do is to test out any interaction between your light and the compass reading - whatever the light. It does seem that headsets with LED/electronics are more prone to the problem.
I'm not a complete idiot: some parts are missing!

Offline SamT

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Re: How to survey 101
« Reply #38 on: March 30, 2007, 01:49:37 pm »
or better still - tape a small flouresecnt light stick (available from fishing shops) over the compass and hey presto - self illuminating compass/clino - no need to have your lamp anywhere near it (i.e. take your helmet off to take the reading.)


 :thumbsup:

Offline graham

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Re: How to survey 101
« Reply #39 on: March 30, 2007, 01:53:15 pm »

Then the difficult bit - I always hand plot the survey - I think the computer generated surveys are poor and a much better looking survey can be achieved using this method. Just my view. It does take time to hand plot and a large drawing board. I then scan the plot and electronically trace the survey then all the information and detail can be added.


The late and extremely lamented, Mr Irwin used to complain vociferously to me about the standard of survey presentation in recent years (decades). He maintained - and I wholeheartedly agreed - that although you can get the magic numbers box to calculate the co-ordinates and even plot them - the final presentation must be done by hand as only that way can you get something that can be properly understood by the user.

Doubtless some of the computer geeks would disagree with me but there is, as yet, no survey drawing program that is both straightforward to use and pleasing in its results.
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Walrus

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Re: How to survey 101
« Reply #40 on: March 30, 2007, 02:25:49 pm »
Doubtless some of the computer geeks would disagree with me but there is, as yet, no survey drawing program that is both straightforward to use and pleasing in its results.

I suppose the way to find out if that statement is correct would be to do one by hand and one by computer then see if you can tell which is which. (yes, I'm a computer geek).

emgee

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Re: How to survey 101
« Reply #41 on: March 30, 2007, 03:35:19 pm »
The Turing Test applied to caving interesting.

Offline axbridgecaver

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Re: How to survey 101
« Reply #42 on: March 30, 2007, 03:49:06 pm »
Doubtless some of the computer geeks would disagree with me but there is, as yet, no survey drawing program that is both straightforward to use and pleasing in its results.

I suppose the way to find out if that statement is correct would be to do one by hand and one by computer then see if you can tell which is which. (yes, I'm a computer geek).

I have used both methods - that's why I use hand plotting.

Offline axbridgecaver

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Re: How to survey 101
« Reply #43 on: March 30, 2007, 03:51:56 pm »
Hi Darkplaces
I can come along to your site with the ACG surveying gear (compas, clino and tape) and give you and your friends a teach in on surveying.
PM if you wish me to come along.
Ahhh thats very kind. I shall have to consort with my team mates. Are you free weekday evenings from 19:30hrs?

Free most evenings except Wednedays (digging night and that is sacred). Next week I am showing visitors around cave sites so evenings may be taken up - but week after 9 - 12 April free.

Offline SamT

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Re: How to survey 101
« Reply #44 on: March 30, 2007, 03:53:44 pm »
With regards hand drawing the final plot. John beck uses AutoCad, something I've used in the past and have tinkered with the bagshawe survey using it.

Its actually quite straight forward to plot survey lines - and you end up with a 3d rotatable wire frame - you can then just 'draw' your cave detail on a seperate layer.

Not sure if the Peak Cavern survey is the same - though I suspect it is.

Im sure most people would agreee that the Peak and Bagshawe surveys are pretty good, with a 'pleasing' result.

Not used survex though.

Offline graham

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Re: How to survey 101
« Reply #45 on: March 30, 2007, 04:35:25 pm »
Sam

What you describe is something that I would describe as hand-drawing the final stage (though I am not sure whether Axbridgecaver would).

These things are never clear-cut, however, and Peak is a good example. The thing is that in long and complex systems, new extensions, especailly ones that add new closed loops through previously known passages (or across the surface) do not just add to the survey but also distort it. Thus the previous drawing can be made redundant. For this reason, many long and "active" caves (in the sense of  ongoing exploration) are frequently presented just by what can be generated by the computer.

What is needed, in my opinion, and has not been addressed by the software pilots that we have is an output file, like a survex plot file, which has additional layers on which the drawing and labelling can be put, as you say John Beck does, but which remain linked back to the data files, so that a modified plot can be dropped onto the "current" drawing (probably with a colour change to indicate changes) so that only minimal changes to drawing and labelling need to be undertaken to keep the main drawing up to date.

Of course different layers could be used for an "overall view" and "close ups" and other variations are possible, and I suspect that this approach might be more fruitful in many cases than current attempst to get the computer to do all the drawing.

Of course I just have the ideas, it's up to the geeks to make 'em work.  :coffee:
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Re: How to survey 101
« Reply #46 on: March 30, 2007, 04:49:51 pm »
Sounds very similar to a lot of 3 dimensional imaging software that can take a whole image and show just blood vessels, lymph nodes, skeleton etc. Unfortunately most of it is quite high-end stuff, expensive & propriatory. But I work for a medical imaging company so I'll see what and if something could be used or adapted (if its available) for surveys.

Offline graham

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Re: How to survey 101
« Reply #47 on: March 30, 2007, 05:00:48 pm »
Walrus:

Is it possible, do you think, to generate a single layer for something like a psd file that can then replace a previous layer in a pre-existing file?

or possibly generate an additional layer, rather than a replacement. (then when one is certain of its placement, the old layer could be turned off or deleted to choice)?

I don't see why this shouldn't be possible, as it's simply (simply, ha, what do I know) the same as converting a survex plot file to a pdf & then pasting that pdf as an additional layer of a psd file.
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Walrus

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Re: How to survey 101
« Reply #48 on: March 30, 2007, 05:18:03 pm »
In principal, yes. Using CAD you can create a drawing using layers. Then, for example, copy & paste your drawing to a new layer, correct/change it, view both layers together (overlaid) then change the new layer to the same as the old one which will overwrite it. NP in 2D but not tried it in 3D. Will test it over the weekend and let you know if it works.

Offline graham

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Re: How to survey 101
« Reply #49 on: March 30, 2007, 05:24:15 pm »
Yeah, got that bit, good.

What I need to do next is persuade the Survex guys (do Wookey or Ollie read this?) to generate output files of the appropriate type.
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