Author Topic: How to survey 101  (Read 14091 times)

darkplaces

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How to survey 101
« on: March 29, 2007, 11:37:42 pm »
Hello,

I have an interest in surveying mines and have made a few attempts at grade 1 maybe 2 surveys. I have progressed to angles and distances and plotting them in a way to create a map that fits together. I am currently using Visio as I cant find anything that just lets me plot straight lines at a set distance and angle.

Now you know what level I am at could anyone help me with surveying, maybe I could help out to survey a cave or mine your working on, be an extra bod to hold the tape or please post any hints and tips from your vast personal experiance welcome.

Thank you

Offline Les W

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Re: How to survey 101
« Reply #1 on: March 29, 2007, 11:44:03 pm »
You can come and survey with me sometime  ;)

Somewhere in Swildons perhaps
I'm a very busy person

emgee

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Re: How to survey 101
« Reply #2 on: March 29, 2007, 11:44:43 pm »
Survex

Offline menacer

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Re: How to survey 101
« Reply #3 on: March 29, 2007, 11:44:58 pm »
Not too sure what youor after however many cavers use "survex" freely downloadable on the web complete with instructions on how to use...
If your about at the weekend I'll bring up my computer and show you to start you off.
What instruments do you use,
a popular brand is suunto, the tandem is a compass and clino in one.
Buy one from the usa 2nd hand for as little as £70 (the geographical settings are the same as uk)
Chaos, panic, and disorder - my work here is done.

Offline menacer

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Re: How to survey 101
« Reply #4 on: March 29, 2007, 11:48:56 pm »
You can come and survey with me sometime  ;)

Somewhere in Swildons perhaps

Of course some people are lucky enough to be going out to matienzo soon where there is ALWAYS surveying going on.
Forgot to mention "Tunnel" another surveying package, dont know if its readily available or not...
Chaos, panic, and disorder - my work here is done.

Offline Les W

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Re: How to survey 101
« Reply #5 on: March 29, 2007, 11:49:54 pm »

a popular brand is suunto, the tandem is a compass and clino in one.
Buy one from the usa 2nd hand for as little as £70 (the geographical settings are the same as uk)


Or as you are a Wessex member you could borrow one of the clubs survey instrument sets  :-\
I'm a very busy person

Offline Les W

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Re: How to survey 101
« Reply #6 on: March 29, 2007, 11:50:44 pm »
You can come and survey with me sometime  ;)

Somewhere in Swildons perhaps

Of course some people are lucky enough to be going out to matienzo soon where there is ALWAYS surveying going on.


You not going this Easter then Menacer  :halo:
I'm a very busy person

Offline menacer

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Re: How to survey 101
« Reply #7 on: March 29, 2007, 11:56:48 pm »
You not going this Easter then Menacer  :halo:
You Git you already know the answer to that one...
 :furious: :annoyed:
 
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darkplaces

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Re: How to survey 101
« Reply #8 on: March 30, 2007, 12:18:30 am »
oo Thanks Mr Les W yes I would like to come along and help survey.

The equipment I have used is a simple Silva compass and 100ft tape measure. The enviroments I am surveying don't need any inclination. I'll try them programs again but they all seamed to be windows 98 and way too complex for what I want. I'm off to North Wales this weekend to do some work on the Cwmorthin slate mine http://www.cwmorthin.co.uk/ otherwise yes I would like to meet up and sort out some proper survey software. Mind you Visio is producing some good results.

Offline Les W

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Re: How to survey 101
« Reply #9 on: March 30, 2007, 12:57:19 am »
Survex is the program of choice - http://survex.com/ - runs on everything!

I will be doing LOTS of surveying next week in MATIENZO using survex, then lots of drinking in Bar German and in Bar Thomas and in the "smoothie bar" and in "Arkwrights bar", oh and in Rianio Bar, etc.  :tease: :beer2: :beer2: :beer2: :beer2:

Sorry Menacer  :lol:
I'm a very busy person

Offline menacer

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Re: How to survey 101
« Reply #10 on: March 30, 2007, 01:17:30 am »
I'll try them programs again but they all seamed to be windows 98 and way too complex for what I want.

It works on xp.
It is too complex if using "notepad" is a problem.
For your data you would write...

 *begin box mines east extension

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 mines east extension

Where the 1st two numbers denote the survey legs, 225 is the compass, 0 is the clino and 3.8 is in metres.
save the notepad file as a .svx file
then right click and use survex to process the file... voila. Line survey....
Easy Peasy lemon squeezy.

give it a go



Chaos, panic, and disorder - my work here is done.

Offline Peter Burgess

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Re: How to survey 101
« Reply #11 on: March 30, 2007, 08:55:39 am »
Hello,

I have an interest in surveying mines and have made a few attempts at grade 1 maybe 2 surveys. I have progressed to angles and distances and plotting them in a way to create a map that fits together. I am currently using Visio as I cant find anything that just lets me plot straight lines at a set distance and angle.

Now you know what level I am at could anyone help me with surveying, maybe I could help out to survey a cave or mine your working on, be an extra bod to hold the tape or please post any hints and tips from your vast personal experiance welcome.

Thank you

Hi DP:

Are the mines you want to survey effectively level, or dipping no more than 10 or so degrees? In which case, try the article below for some ideas. The advice you have so far will provide you with a line survey, but the real value of a good mine survey is in the detail, which you add to the survey. The notes in the article about taking offsets, and making good sketches and notes to add details to your line survey are important.

If you are talking about steep slopes and vertical sections, then obviously the extra dimension makes a big difference to how you create your line survey, but the addition of detail is much the same procedure - offsets and good sketch notes.

A shallow dip angle will not have an appreciable affect on the accuracy of a plan survey if you assume it to be level, unless you want to really super accurate.

http://www.wcms.org.uk/pages/u2nl1983_1.shtml#surveying_chaldon_spring1983

Offline Peter Burgess

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Re: How to survey 101
« Reply #12 on: March 30, 2007, 08:58:14 am »
I should add that it is important to make the notes and offsets at the time you do each leg of the line survey, and not at a later date! Don't be tempted to rush ahead with just the line work without details, as in the long term it will take longer if you want a good detailed result.


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Re: How to survey 101
« Reply #13 on: March 30, 2007, 09:09:14 am »
When surveying, even in mines, please please please take inclination data as well as length and direction (and the passage detail Peter talks about). You may not think it adds much to the accuracy of your plan, but those using your data set in years to come, geologists for example, will be extremely grateful for teh small extra effort taken.
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Offline Peter Burgess

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Re: How to survey 101
« Reply #14 on: March 30, 2007, 09:26:57 am »
In an evenly-dipping bed of stone, the angle of dangle need only be measured later at key points in the workings, to add the required geological value. In folded and distorted beds, assuming the mine is following a particular bed, Graham's comment is a good one. The Surrey mines are by and large in gently folded strata and the plan survey, which was undertaken primarily for archaeological reasons, is perfectly adequate.

Offline Cap'n Chris

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Re: How to survey 101
« Reply #15 on: March 30, 2007, 09:31:51 am »
Surveying's fun and exciting.  :thumbsup:

Offline graham

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Re: How to survey 101
« Reply #16 on: March 30, 2007, 09:34:26 am »
Caving is for Life not just for Christmas

Walrus

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Re: How to survey 101
« Reply #17 on: March 30, 2007, 09:34:54 am »
I'll try them programs again but they all seamed to be windows 98 and way too complex for what I want.

It works on xp.
It is too complex if using "notepad" is a problem.
For your data you would write...

 *begin box mines east extension

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 mines east extension

Where the 1st two numbers denote the survey legs, 225 is the compass, 0 is the clino and 3.8 is in metres.
save the notepad file as a .svx file
then right click and use survex to process the file... voila. Line survey....
Easy Peasy lemon squeezy.

give it a go





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!

Offline Peter Burgess

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Re: How to survey 101
« Reply #18 on: March 30, 2007, 09:37:50 am »
Another thing to think about is magnetic variation. You should take this into account, of course, when you are plotting your results, but there is one other factor which many don't bother with. That is temporary magnetic variation anomalies, caused by things like solar storms.

Every survey session, you should do a check bearing between two known points. This should be consistently the same every time, apart from the normal drift of magnetic north over the years, which won't be an issue if your survey only takes a few weeks. However, if you get a temporary anomaly in mag north, the check bearing you take will pick it up. In all the years of surveying in Surrey, we only noticed this once, but had we not allowed for it in the plotting, we would have had some errors, and poor loop misclosures.

For our check bearing, we used a sturdy (non-steel) gate-post, and sighted onto a clearly visible mast a few kilometres away, with a bright red light on top. Useful, for late night surveying! Only problems were on foggy nights, but I can't recall this being a problem very often.

Offline Peter Burgess

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Re: How to survey 101
« Reply #19 on: March 30, 2007, 09:38:53 am »
Surveying's fun and exciting.  :thumbsup:

 :-\

Each to his own, Graham. I understand you and Chris enjoy the fun of replacing bolts.

darkplaces

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Re: How to survey 101
« Reply #20 on: March 30, 2007, 10:22:22 am »
Surveying's fun and exciting.  :thumbsup:
It is when you found something new(ish)  ;D or want a survey you can publish without copyright issues. I like filling in the details like '5th Sep 1896' written on the wall.

ooPS I had forgotten things like MAG to GRID getrid and GRID to MAG add. Everything is MAG so trying to overlay it would be all a skew by 6deg.
The check angle is a good point as I would hate to be using a bad compass and not know it.

Walrus's experience of the survey software mirrors mine.

Cheers for the info so far, glad I asked now.

Dep

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Re: How to survey 101
« Reply #21 on: March 30, 2007, 10:28:13 am »
...
ooPS I had forgotten things like MAG to GRID getrid and GRID to MAG add. Everything is MAG so trying to overlay it would be all a skew by 6deg.
...

Be careful, the error is much less than that and hanging noticeably over time.
It was about 6deg when I first learnt about this as a teenager,nowadays it is closer to two deg IIRC.

OS 1:50K will give angle, date and expected change over time.

At some point in the next few decades the error will reduce to zero before starting to increase again.


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.

A great piece of software - very impressed.



Dep

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Re: How to survey 101
« Reply #22 on: March 30, 2007, 10:29:30 am »
Modify has gone AWOL....
Quote
Be careful, the error is much less than that and hanging noticeably over time.

I meant to write...
Quote
Be careful, the error is much less than that and changing noticeably over time.

Offline Peter Burgess

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Re: How to survey 101
« Reply #23 on: March 30, 2007, 10:38:44 am »
DP's point about using a check bearing to check your compass against a map is good. Forgot to mention it earlier. Also useful if you use a different compass - check them against each other.

Offline graham

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Re: How to survey 101
« Reply #24 on: March 30, 2007, 10:54:51 am »
DP's point about using a check bearing to check your compass against a map is good. Forgot to mention it earlier. Also useful if you use a different compass - check them against each other.


It's not good, Peter, in any survey with pretrensions to accuracy, it is essential. Every compass will have a built-in error of a couple of degrees and magnetic variation will account for a fair few degrees more (or less if the errors cancel out slightly.

What is more is that magnetic variation can vary on a daily basis so, for surveying purposes, every compass needs to be calibrated against a known bearing every time it is used.
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