Starting to Survey: gear options?

[Swallowneck]

Opinion Of A Novice Surveyor.


Until this year I had never done any surveying-ever! I had a go with tape/compass etc but had a bit of a nightmare. Obviously it can be done but requires patience and no small amount of skill to get accurate data.
I then got a Distox and Beat Heebs conversion kit and put it all together. Not too difficult if you follow the excellent instructions on the website. Surprisingly it worked perfectly when turned on. Then came the PDA from ebay. ?15 got a Dell PDA,charging cradle and a box of other stuff. Several hours later after struggling with Active Sync,com ports and the Bluetooth I had pocket toppo up and running and talking to the Distox and my PC.
Now I had to do something with this new kit, I went on the paperless surveying course at Bull Pot Farm in Feb and came away with my head swimming with new information a lot of which at the time made very little sense. What we did learn was the basics of using the Distox and PDA and getting data output to a PC. This as it turns out is the easy bit as we were then shown the basics of Therion which for me turned into a bit of a brain meltdown moment. We were also shown what Therion could do in the right hands, this really gave me the motivation to get stuck into and learn this software as the stuff we saw was fantastic.
Having now used the Distox and the PDA combo in a cave and sussed out the best workflow it really is not that difficult, I would hesitate to use the word "easy" but it's not far off. Therion on the other hand is more difficult although this last couple of weeks it is starting to come together and I am quite pleased with the outputs I'm getting. It's a BIG learning curve but hopefully I will stick at it and start to produce some good accurate surveys.
One thing I have noticed is that when you compare our Distox data with older surveys there are some major discrepancy's which of course could be me but as we survey our training passages again and again we will find out.
So Amy if you can I would get a Distox it is loads quicker and has to be less prone to errors, it is also quite good fun. That's something I never thought I'd hear myself say about cave surveying.       

 

[Amy]

Thanks for that review. I dont know therion, i have used walls and compass breifly.

I still have yet to understand where a disto is purhased from. Their website only has software downloads. Where is the hardware? Whats the cost? Are there multiple hardware options if so which one(s) work with the cave software on the survey website people link to? Etc.

 

[graham]

To mmilner

PocketTopo can run on a Windows Laptop as well as a PDA.
The DistoX2 data is downloaded to PocketTopo and you then have the option of exporting a PocketTopo formatted file, a Therion format file or a good old fashioned txt file. I go for txt, then edit in excel before creating a Survex file.

Thanx Kev. Does it run on Linux as well, do you know? My laptop runs Win 7 and Linux (which I normally use), though I could always run it in a VM. I will do some googling, lol. 

Therion and Survex both run on Linux. If you are using PocketTopo on a PDA to gather your data then I thoroughly recommend TopParser to export to Therion, saves much time & means you get a Survex 3d file before you've finished your first cup of tea after the trip. (The manual is particularly well-written  8) )

 

[graham]

Thanks for that review. I dont know therion, i have used walls and compass breifly.

For me the most interesting bit of Compass is Larry's new map-to-data tool, very useful indeed. Walls confused me no end, probably because I am used to the file structure of Survex and Therion.

I still have yet to understand where a disto is purhased from. Their website only has software downloads. Where is the hardware? Whats the cost? Are there multiple hardware options if so which one(s) work with the cave software on the survey website people link to? Etc.

You don't purchase a DistoX, you purchase a particular model of Leica Disto plus a separate upgrade board from Beat Heeb. You then install it yourself (or get a mate who is good at electronics to do it for you).

 

[bograt]

Amy, try googling "Disto X".

 

[martinm]

To mmilner

PocketTopo can run on a Windows Laptop as well as a PDA.
The DistoX2 data is downloaded to PocketTopo and you then have the option of exporting a PocketTopo formatted file, a Therion format file or a good old fashioned txt file. I go for txt, then edit in excel before creating a Survex file.

Thanx Kev. Does it run on Linux as well, do you know? My laptop runs Win 7 and Linux (which I normally use), though I could always run it in a VM. I will do some googling, lol. 

Therion and Survex both run on Linux. If you are using PocketTopo on a PDA to gather your data then I thoroughly recommend TopParser to export to Therion, saves much time & means you get a Survex 3d file before you've finished your first cup of tea after the trip. (The manual is particularly well-written  8) )

Hiya. soz, but I was specifically asking Kev about PocketTopo on Linux, I already have Survex and Aven running, but had bad problems trying to compile Therion a few months ago, so gave up. I have it running in Win 7 though, so not too much of a problem, just reboot into the other OS temporarily.

PocketTopo on Linux would be great. TopoDroid sounds interesting, I will investigate. 

PocketTopo for Android sounds good as

 

[sluka]

http://paperless.bheeb.ch

 

[sluka]

TopoDroid sounds interesting, I will investigate. 

It is good application to calibrate DistoX, but nothing more. The idea to draw a final map in cave is not very good. Just to sketch is much much faster!

 

[jarvist]

So everyone is split between disto!!!! Or old school.

Personally, for whom surveying is part of exploration, and for which the centreline is the key result, the simplicity, ruggedness and flexibility of manual instruments beats everything else.

Amy, you mentioned Tandems above; I don't like these. I think they're much more prone to breakage (smashing the dial), and more bulky to transport and more irritating to use than separate compass / clino. (For transport through hte cave, you can pack the separate instruments facing dial-to-dial, wrap the neckcord strings around them, then slip them into a single one of the 'Suunto' black velcro-closure nylon bags.)

There's a lot of traditional instruments out there, ask around and I'm sure you'll be able to find a working pair to borrow. Supplementing this with a laser disto (such as the Bosch DLE) rather than a tape makes a very compact setup.

(Though again, laser distos have their own subtleties. They're amazing for doing splay legs (and ceiling height), but easy to 'miss' the station and get an erroneous measurement, so you have to fire a few shots / get the 2nd surveyer to hold the book perpendicular from the station as a target.)

I prefer recording the data with offset arrows, the most recent survey books we made were based on the 99p Gelert waterproof paper books, with this design traced by ruler + coloured fine-line indelible pen:
https://union.ic.ac.uk/rcc/caving/FILES/survey_book_arrows_2010_name_survey.pdf

 

[graham]

(Though again, laser distos have their own subtleties. They're amazing for doing splay legs (and ceiling height), but easy to 'miss' the station and get an erroneous measurement, so you have to fire a few shots / get the 2nd surveyer to hold the book perpendicular from the station as a target.)

I'm fairly certain that someone did a bit of research when distos first became available and showed that even 'good' surveyors were seriously rubbish at estimating ceiling height to any sort of accuracy.

As for missing the target, that's another advantage of using a DistoX with Pocket Topo in that the reading is only 'accepted' if you get three shots within close agreement. Splays are single-shot, but all proper legs have to be triple shot. Much more reliable & frankly little different in timing.

 

[sluka]

(Though again, laser distos have their own subtleties. They're amazing for doing splay legs (and ceiling height), but easy to 'miss' the station and get an erroneous measurement, so you have to fire a few shots / get the 2nd surveyer to hold the book perpendicular from the station as a target.)

It all depends on choice of station points. Second, all surveyors they use Disto use a "target" just after point - palm, notebook, special target, etc. Combination of timer and target eliminate the possibility to miss the station point.

Check http://cachtice.speleo.sk/laser/ there is an idea how to make a target for Disto.

Try it! One time!

 

[jarvist]

As for missing the target, that's another advantage of using a DistoX with Pocket Topo in that the reading is only 'accepted' if you get three shots within close agreement. Splays are single-shot, but all proper legs have to be triple shot. Much more reliable & frankly little different in timing.

For sure, and of course, anyone using a disto by hand would also be triple-checking the measurements. The fundamental problem is that this isn't a check on accuracy, but a check on precision. The devices are actually doing this themselves internally, which is why they sometimes 'hunt' for a while after pressing the button (particularly when it's foggy and there's lots of extraneous reflections). They're taking multiple measurements and then voting on the distributions returned.

There's massive potential for systematic error here, when you are either catching an obstruction before the target, or missing the target and hitting the far wall.

Fundamentally, I cannot hold a laser disto steady to less than a degree (probably worse when tired / cold), so I need to be using a station target to improve on accuracy beyond tape. The book makes a good target.

 

[kdxn]

To answer mmilner's question about PocketTopo on Linux. I have not tried this but now you can get a Windows emulator for Linux so that be a solution.

Amy
More detail about the DistoX2 can be found in this forum topic
http://ukcaving.com/board/index.php?topic=16012.0

Note Beat now ships the Micro-USB breakout board as part of the upgrade kit.
I will not post his email address here in case it gets picked up by the spiders.
It appears lower down as a blue graphic on this webpage
http://paperless.bheeb.ch/

Given you're stateside, check out the NSS surveying DistoX2 forum topic, might be someone near you that has already done the build. Note the USA Disto model you need is the E7400X which has a default unit of feet.
http://www.forums.caves.org/viewtopic.php?f=26&t=14816

As for being split between old school and Disto.
I think you will find that most active cave surveyors are using DistoX1 or DistoX2 but they may be too busy surveying to post their opinion on these forum.

 

[jarvist]

I think you will find that most active cave surveyors are using DistoX1 or DistoX2 but they may be too busy surveying to post their opinion on these forum.

I think you're probably quite right; my point is that  most active cave explorers are surveying their finds with manual instruments.

 

[graham]

As for missing the target, that's another advantage of using a DistoX with Pocket Topo in that the reading is only 'accepted' if you get three shots within close agreement. Splays are single-shot, but all proper legs have to be triple shot. Much more reliable & frankly little different in timing.

For sure, and of course, anyone using a disto by hand would also be triple-checking the measurements. The fundamental problem is that this isn't a check on accuracy, but a check on precision. The devices are actually doing this themselves internally, which is why they sometimes 'hunt' for a while after pressing the button (particularly when it's foggy and there's lots of extraneous reflections). They're taking multiple measurements and then voting on the distributions returned.

There's massive potential for systematic error here, when you are either catching an obstruction before the target, or missing the target and hitting the far wall.

Fundamentally, I cannot hold a laser disto steady to less than a degree (probably worse when tired / cold), so I need to be using a station target to improve on accuracy beyond tape. The book makes a good target.

We still use a 3 man team most of the time. Instrument man, data man and dog. Although the dog is no longer on a lead, he does still hold the target, to ensure that it is in position and also watches to ensure the red dot from the laser is on the target and stays there. The target is usually a yellow plastic square of 10 cm sides. (that's about 4", Amy). That's large enough to be seen & not mislaid, but the dog usually states "centre left" or "top right" to indicate where the marked station is and to ensure that the station position error remains acceptable.

 

[graham]

I think you will find that most active cave surveyors are using DistoX1 or DistoX2 but they may be too busy surveying to post their opinion on these forum.

I think you're probably quite right; my point is that  most active cave explorers are surveying their finds with manual instruments.

Cannot speak for 'most' but on Mendip, the two most recently explored major caves, Reservoir Hole and Charterhouse Cave were both surveyed using DistoX/PDA and the same kit has been visiting Austria these past few years (dunno what they do with it there, mind ).

 

[kdxn]

DistoX2 builds here in UK are gathering momentum, 35 so far that I know of.
Many of these are on expedition or are destined for an expedition later this year.

The prudent surveyor will always have some backup instruments available especially on expedition whether it be another DistoX or a set of Suunto instruments plus plain Disto and writing pads. A camera also makes a good surveying tool for expedition use to photograph used writing pad sheets. 

 

[estelle]

As someone who has dodgy eyeballs - astigmatism and also left eye dominant while right handed - i always found it quite hard work using the compass and clino which made me quite slow so purchasing a DistoX for expedition surveying (and if/when we find cave at home too!) was a no brainer for me. It is so easy to use and the display is obvious and clear. I've seen it in use with a PDA, but not used it myself as with a good 'book' person, it always seems pretty quick doing it that way. Agree with comment above about team of 3 tends to work best for speed of the book person focussing on the book only, as they are not having to spot good station points and mark them - we've tended to use a combination of tippex and/or nail varnish to mark survey points.

Am interested in the idea of the PDA usage though - can anyone recommend a good budget device that works well with Pockettopo and the cave environment/battery usage/etc.?

 

[graham]

As someone who has dodgy eyeballs - astigmatism and also left eye dominant while right handed - i always found it quite hard work using the compass and clino which made me quite slow so purchasing a DistoX for expedition surveying (and if/when we find cave at home too!) was a no brainer for me. It is so easy to use and the display is obvious and clear. I've seen it in use with a PDA, but not used it myself as with a good 'book' person, it always seems pretty quick doing it that way. Agree with comment above about team of 3 tends to work best for speed of the book person focussing on the book only, as they are not having to spot good station points and mark them - we've tended to use a combination of tippex and/or nail varnish to mark survey points.

Am interested in the idea of the PDA usage though - can anyone recommend a good budget device that works well with Pockettopo and the cave environment/battery usage/etc.?

The thing about using PocketTopo and a PDA is that you then have far greater flexibility for taking splays, the result becomes more like a low-res laser scan than a conventional line survey. With a book, you really are just limited to LRUD. This is fine in uniform canyon passages, but not in most places.  One interesting factoid on this is that Andrew Atkinson's estimate of the floor area of The Frozen Deep in Reservoir based on the Distox/PDA survey was very little different to Kevin's from the laser scan. I'd like to know just how long it would have taken a conventional surveyor, or indeed a DistoX/book combo to match their results.

 

[kdxn]

A DistoX and notebook is not just limited to LRUD.
In my note taking, I write down the traverse leg distance, clino and bearing and where I would normally have put the LRUD measurements, I write "Splays", this is my note to myself to indicate what to do with all the stored DistoX2 data. All the downloaded data between the two traverse legs are splay measurements from the station that started the first traverse leg. I have got into a routine with this and have had no problems with it. Even revisiting older stations that were previously done with a plain Disto and doing Splays only from those stations with a DistoX2.

My surveying is as a two person team. 
Myself operating the DistoX2 and writing pad. Second person scouts ahead, selects survey stations and uses a laminated target card for the DistoX2.

PDA options.
A number are using Dell Axim X51V.
These are low cost and readily found on ebay etc.
You can get extended battery packs for them.
They are not cave proof and need some sort of container.
I have an Otterbox with flexible screen but these are no longer made and hard to find.
Others are using flexible waterproof pouches that allow the stylus to be used through them.
To use PocketTopo on a Dell Axim X51V, you need to install Microsoft .NET framework 2.0. This can be awkward for some but you need to find the CAB file for WM5 and ARM4i and install this on the Axim SD card and then click it, it will reboot and then you can run PocketTopo. Do not select Secure when setting up the Bluetooth connection.

There are other PDA options out there including ruggedised options but these tend to be expensive and you need to be careful that the operating system is compatible with PocketTopo.

There are other cave survey programs and developments underway including an Android program.
I suggest  PocketTopo for now as that appears to have a large user base in UK and is taught on the Digital Cave Surveying course periodically run by the Cave Surveying Group.