Technology for Mapping the Underground? 41
Archon-X asks: "As an avid CaveClanner, I spend my spare time sloshing around underground in drains, and have more than once considered 'mapping' the drains. How would readers approach this problem? Mobile reception and presumably GPS is non-existent, and it's pretty dark and wet down there."
Use a... (Score:1, Redundant)
Seriously though.. You track around the sewers for fun? You seriously need a new hobby.
Re:Use a... (Score:4, Funny)
Hey, don't forget your dice! Last time I let you borrowed mine, you stole my silver-speckled 20-sided die!
Re:Use a... (Score:1)
Re:Use a... (Score:2, Insightful)
Hey. Where I come people *have* the right to voice uninformed opinions such as that.
Re:Use a... (Score:1)
Re:Use a... (Score:1)
You also need a 'Clino (inclinometer (sp?)), and a compass, and a tape measure.
This has been done thousands of times, google for cave surveying, I'm sure you'll find plenty of ways to do it.
The hi-tech aproaches I've thought about all fall down on one crucial point - very little electronic gear survives caving. Hell, even caving lamps have a limit
Municipal & Private Organizations (Score:3, Informative)
For most mines and caves and such, if the company which bore the caves is still in existance, they may have maps and such for the caves and so on. If not them, then national archives. National archives or local government agencies may also have maps for the stormwater drains, as well.
Paid exploration (Score:2)
GPS can still help (Score:3, Informative)
Caving (Score:3, Interesting)
Depends what you're after. lots of string and a compass will give you distances and directions, used correctly.
to measure the size of rooms, check with architect friends about measuring all dimensions of a space manually
For crazy insane measurements of large caves, try surveyors tools.
If you're posting this on
mug
Re:Caving (Score:2)
Something tells me that being inside a big metal pipe might screw with the compass a wee bit.
Well, you did ask... (Score:1)
Re:Well, you did ask... (Score:1)
Play D&D (Score:2)
Start on the surface (Score:3, Insightful)
This should give you some points of reference that you can build the rest of your map around.
You might also want to plot those locations on a topographic map, or an arial photo, and play "connect the dots" to try to figure out a simple overview of how the drain system is layed out. Once you have the overview, you can fill in more details as you explore.
Inertial Navigation (Score:5, Informative)
There are some highly sensitive solid-state accelerometers. I believe that they are manufactured by National Semiconductor. Microsoft uses them in their handheld Sidewinder FreeStyle Pro. They look like fat silicon chips and the interfaces are digital, so they are easily connected to microcontrollers.
If you need higher precission, you could add gyroscopes. Laser gyroscopes are popular this days and their prices have come down quite a bit.
When you combine accelerometers with gyroscopes and a fairly high sampling rate, you can obtain high degrees of accuracy and precision.
If you can use waypoints, then you can calculate drift rates and improve accuracy. If you think that the GPS signal may be usable then you can use a GPS receiver as a waypoint source.
From my experience, the most common source of errors is high frequency content, specially when walking. A damper would go a long way towards improving the accuracy.
You should have no problem integrating everything into a small backpack with a laptop (if you need a UI), or a small shoe box if all you want is data logging.
Hope this helps, if you want more information such as part numbers and suppliers, I could gather some. As for designs and software,
Hector
Re:Inertial Navigation (Score:3, Informative)
Re:Inertial Navigation (Score:1)
Re:Inertial Navigation (Score:1)
Seriously, anyone who takes delicate (i.e. shock sensitive, water sensitive, dirtt sensitive) equipment underground is just asking for trouble.
compass & pedometer (Score:3, Insightful)
gps has made people very, very lazy. navigation isn't rocket science.
Re:compass & pedometer (Score:2)
you're crawling on your belly?
Re:compass & pedometer (Score:2)
large ones can be had here:
http://www.surveyorsupply.com/
coming up with complex and expensive technical solutions to trivial problems is retarded. people have been mapping & surveying for thousands of years.
Re:compass & pedometer (Score:2)
Or is it that in the sewers you can always walk another block and find a manhole?
string and a compass! (Score:1)
You could use a compass for heading, and a string for distance. I don't know how you would easily measure the length of the string though. Perhaps put it on a wheel with a counter? For straight shots, you could probably use one of those laser range finders...this would require two people, one at each end, but it might work.
I highly doubt the ultrasonic range
MicroGPS? (Score:3, Interesting)
Hmm, I guess re-inventing GPS technology would be very expensive. Never mind!
careful (Score:2)
A maze of twisty passages, all alike... (Score:5, Funny)
What you'll need: Pen and paper, and lots of objects (at least one for every room).
What to do: Drop an object in the first room, which we'll call room #1. Make a note of what object you dropped in room #1 (let's say it's a sword). Put a '1' on the paper, with eight lines coming out at the compass points. Pick one at random (let's say north) and go that way.
You'll be in another room, which we'll call room 2. Drop another object (say, a bell), and make a note. Put a '2' on the paper, with eight lines coming out at the compass points. Finally, put a little '2' next to the line from room 1 you used to get here (in this case, north). You now know that going north from room 1 leads to room 2. Pick another direction (say, north again), and continue.
If you end up in a room without an object, it's a new room, and you repeat the instructions above. If it's a room containing an object you dropped, then you just need to make a note on the appropriate line from the old room. Pretty soon, you'll have the whole maze mapped.
Unless the thief comes by and picks up some of your objects. That'll mess you up. I recommend killing him first.
Mapping sewers. (Score:5, Informative)
1.A compass works well in older systems composed of brick or clay tiles. Concrete pipe and box culverts often have enough iron in them to really mess up your compass.
2.Most cities have "Atlas sheets" available for all city utilities. Water, storm, and sanitary are often listed on the same sheet. You can usually find these at the municipal utility complex - for free. Just tell the clerk at the counter you are doing a topographic survey for new development, and need to show such on your plot.
3.I have used a cordless drill, concrete bit, and concrete screws to set points in the ceiling of pipes, at angle points. Use string and a protractor to measure angles. The screw also provides a nice hook to pull tape distances with. There is no way I'm taking a 20 grand total station into the sewer!
4.Put the tip and straw from a can of WD-40 on a can of funky coloured spray paint. Use the straw to spray out of the manhole lid. This can help you tie your underground survey in with aboveground locations.
5.Always be thinking like water. Water flows downhill. (duh) You aren't going to find that 10 foot dia. pipe very far from the local river or stream, or whatever your natural drain is. Take a johnboat or raft or such on a slow paddle down the riverbanks, looking for the big outlet pipes, and start your adventure there.
6.Methane or carbon dioxide poisoning is NOT a major risk in STORM sewers. Watch it in older systems, though. Many of the older ones are combined - still. If there is organic debris on the floor of the pipes you are exploring, that is also a cause for alarm about gas. Clean bottom storm pipes are almost always safe.
Those who said they have used GPS anywhere underground, near a lid or not, are full of it.
Who wants to carry a 4' level in the drains? What will you do with it? If you want to measure slope - get a combo compass/inclinometer or fancy yourself one out of the protractor you are using to measure bends.
Only one way to map a storm system - old school two man. Measure the angle and chain the distance!
Re:Mapping sewers. (Score:1)
But they are called storm pipes for a reason -- Always check the weather forecast before exploring. And even if you are covertly exploring, make sure someone knows where you are and your timetable. (Obvious perhaps, but safety first!)
Do it like a real caver (Score:4, Informative)
Survex (Score:2, Informative)
Re:Survex (Score:1)
"Clit" - convert literature
Re:Survex (Score:1)
For info, from the site owner:
"my slashdotting is up to 21 hits now. at peak I was received 2 hits per minute. it's a tribute to linux that the server stayed up"
;-)
We already have one? (Score:2)
I have a solution (Score:2)
In short, what I would propose is a pair of optical/LIDAR mapping units, with a tripod or other stable mount. One would also be equipped with a GPS for initialization. The way they would work is:
Set up the GPS-equipped unit outside the entrance to the underground system. Allow it to acquire a GPS fix to reference the entire system to the real world
Re:I have a solution (Score:2)
Has anyone done anything like this? I'd think that it would be an obvious application. (Now that I've thought of it. :^) Perhaps the "bots shooting each other" was too neat an idea?
Mapping Caves (Score:1)