Posts: 0
Threads: 0
Joined: Dec 2007
26th April 2012, 03:51 PM
kevin wooldridge Wrote:Yep Jack is right....photograph the damn cobbles/burial mound/prehistoric mortuary enclosure...use the GPS or total station to zap in a few randomly placed targets, georeference and then digiitise the rectified photos at your leisure.....
I know the thread's moved on from the hand drawn/rectified photograph/EDM or GPS planning discussion, but I thought people might find these 3D Laser Scanned plans that I just came across to be of interest. I'd not previously seen such technology used on a commercial site - apparently relitively cheap and speedy.
As with everything using the right technique for the right situation is key, but the results look pretty impressive. It's not a technique I'm that familiar with - I'll have to go off and do a bit of background reading.
Quote:The complex nature of these industrial structures meant that recording by conventional survey and planning methods would be expensive on time and labour. The survey firm J C White was brought in to record the furnaces using laser scanning technology, a method that has only become practical for use in archaeology during the last few years. The laser scanner emits thousands of laser pulses a second and as it traverses the site, records the time taken for each pulse of the beam to be reflected off any solid surface, from which in turn, each distance can be calculated to a few millimetres? accuracy. Setting up the equipment in different locations thus allows what is termed a ?point cloud? to be constructed, a virtual 3D image of the solid artefact that can then be manipulated with computer software to form an accurate plan, sections or a 3D model. Using this technology, Areas C and D were surveyed within a day.
Preliminary data:
http://www.canterburytrust.co.uk/catpres..._AREA2.jpg
3D Oblique view of the 3D model:
http://www.canterburytrust.co.uk/catpres..._area1.jpg
Full details of the project can be seen here - http://www.canterburytrust.co.uk/news/pr...aper_mill/
Posts: 1
Threads: 0
Joined: Apr 2010
26th April 2012, 05:12 PM
P Prentice Wrote:i think jack is correct and 'constrained' means the reseach design was inadequate
Long and sometimes bitter experience with research designs in relation to sampling strategies suggests that they often (usually!) turn out to have relevence only within the confines of the original trial trench(s) upon which they're based (spot someone gradually becoming disillusioned with trial trenching as a form of evaluation on many projects)....and by the time the 'advisor' can find a free time slot you've usually had to have dug most of the site anyway. Generally manage to come up with some decent sample results anyway off my own bat, luckily, making it up as I go along, just need to know what you're doing :face-approve:
Posts: 1
Threads: 0
Joined: Jun 2005
27th April 2012, 08:52 AM
tmsarch Wrote:I know the thread's moved on from the hand drawn/rectified photograph/EDM or GPS planning discussion, but I thought people might find these 3D Laser Scanned plans that I just came across to be of interest. I'd not previously seen such technology used on a commercial site - apparently relitively cheap and speedy.
As with everything using the right technique for the right situation is key, but the results look pretty impressive. It's not a technique I'm that familiar with - I'll have to go off and do a bit of background reading.
Preliminary data:
http://www.canterburytrust.co.uk/catpres..._AREA2.jpg
3D Oblique view of the 3D model:
http://www.canterburytrust.co.uk/catpres..._area1.jpg
Full details of the project can be seen here - http://www.canterburytrust.co.uk/news/pr...aper_mill/
Very interesting. We've used this on a couple of jobs where traditional building recording wouldn't have been possible for safety reasons. One of the systems used by our sub-contractor uses a digital camera connected to the scanner. During processing, the colour information from the photographs is interpolated and used to colour the point cloud model. It's strangely effective.
D. Vader
Senior Consultant
Vader Maull & Palpatine
Archaeological Consultants
A tremor in the Force. The last time I felt it was in the presence of Tony Robinson.
Posts: 0
Threads: 0
Joined: Oct 2006
27th April 2012, 09:09 AM
(This post was last modified: 27th April 2012, 09:22 AM by Unitof1.)
http://www.canterburytrust.co.uk/catpres..._AREA2.jpg
This "image" seems to have white lines drawn in it. How did they get there and what are they supposed to represent? By what method was the site excavated?
Wall following?
Reason: your past is my past
Posts: 0
Threads: 0
Joined: Nov 2011
27th April 2012, 10:26 AM
Quote:Very interesting. We've used this on a couple of jobs where traditional building recording wouldn't have been possible for safety reasons.
And was it cheaper than the usual survey methods?
Posts: 0
Threads: 0
Joined: Feb 2011
27th April 2012, 10:32 AM
Dinosaur Wrote:Long and sometimes bitter experience with research designs in relation to sampling strategies suggests that they often (usually!) turn out to have relevence only within the confines of the original trial trench(s) upon which they're based (spot someone gradually becoming disillusioned with trial trenching as a form of evaluation on many projects)....and by the time the 'advisor' can find a free time slot you've usually had to have dug most of the site anyway. Generally manage to come up with some decent sample results anyway off my own bat, luckily, making it up as I go along, just need to know what you're doing :face-approve:
aye - learnt from experience but not from a book
If they can get you asking the wrong questions, they don't have to worry about answers
Posts: 0
Threads: 0
Joined: May 2010
27th April 2012, 11:57 AM
(This post was last modified: 27th April 2012, 12:02 PM by overseas.)
Hi
Sorry, I know you've moved far away from planning issues, but I have to come back really strongly and support Chiz's comments on the problem of de-skilling through over-reliance on technology. Its not just that people lose the quality manual skills, it also contributes to the alienation process that turns individuals from highly motivated "archaeologists" to disillusioned "diggers". Disconnection from the process is...from my observation and personal experience... one of the most damaging aspects of modern archaeology : watching colleagues..highly intelligent and well-educated..gradually atrophying towards brain-death because they can't "tune in" to the potential interest of what they are doing is something I have seen over and over in twenty-five years on site.The more hands-on skills that are in your own hands, the more opportunity you have to "tune-in".
And, with one major exception, I have yet to see technology really gaining time and quality over hand-drawing, scanning and illustrator digitizing : rather, I have seen a lot of time lost - undoubtedly due to poor process rather than an innate flaw, but it keeps happening. Management also tend to under-budget the real post-ex costs of digitising fom rectified photography, behaving as if the "technology" has already solved the problem - as if by magic - on site.
The major exception is professional rectified photography for mosaics - and they still have to be re-digitized in post-ex, but maybe the programmes for conversion exist : we had n't budgetted for it, so I didnt ask. In addition, the skilled professionals who undertook this reckoned they could record the whole site (walls and all) in 3D in about 5 days (7000m2 of buildings). In spite of my above comments, I might be interested to see that done... on the other hand the drawing would then only be a "picture", not an interpreted representation : I suspect the overall quality of site recording and understanding would go down. However, I would still be interested to see the results of recording this way, my above comments on possession of process notwithstanding.
Finally...if you know you will hand-plan, and the team are good at it, overall it can work out faster than laying-out and post-ex rectifying photographs : the post-ex work can after all be done by anyone who can use illustrator rather than having to wait for the skilled surveyor/illustrator using a more complex and slower process.
I have nt seen/used the joys of pen-map et al, but apart from the above exception, I still find hand-drawings (to be inserted into an EDM or GPS general plan obviously) the best and most efficient way to obtain detailed representation of many, many walls (if they still have to be stone-to stone drawings). (I would acquiese to RP for the cobbled surface probably). And, for the reasons stated above, I would much rather work with a team still capable of doing this, than one that has delegated their once-cherised skills to machines - I believe they will better archaeologists doing better archaeology. Its not just nostalgia.
There is a lot more to said on this subject, but I wont...here and now.
Posts: 1
Threads: 0
Joined: Jan 2009
27th April 2012, 12:12 PM
Dinosaur Wrote:Long and sometimes bitter experience with research designs in relation to sampling strategies suggests that they often (usually!) turn out to have relevence only within the confines of the original trial trench(s) upon which they're based (spot someone gradually becoming disillusioned with trial trenching as a form of evaluation on many projects)....and by the time the 'advisor' can find a free time slot you've usually had to have dug most of the site anyway. Generally manage to come up with some decent sample results anyway off my own bat, luckily, making it up as I go along, just need to know what you're doing :face-approve:
Yep, flexibility is always very important as things on site have a habit of turning into something other than the preliminary works said it was. I've seen concentrations of pits full of nearly unique bronze age pal-env evidence turn up in areas of 'no or little archaeology'; iron age/ Roman period settlement associated pits turn into a landscape of neolithic to bronze age activity etc etc.
The key is keep the soil until you know whats going on..............once its on a spoil heap the evidence is contaminated and destroyed. You can always chuck the sample if it turns out to be useless.
Sample every feature, try and keep sample sizes the same and equally spread over areas of intense (for distribution-based stuff later), try and take an equal number of samples from different phases of activity (if you can) for chronological changes in activity..................but also important is to review your samples and chuck away stuff thats no use before you spend loads sending it off to an office/ specialist for floatation.
Don't get me started on rubbish and inappropriate use of geophysics, fieldwalking, DBA and trial trenching to 'define to limit of the archaeology' before the topsoil is stripped and how much get missed in areas released to construction as a result.  !
Posts: 1
Threads: 0
Joined: Jan 2009
27th April 2012, 12:21 PM
overseas Wrote:Hi
...............<snip>
And, with one major exception, I have yet to see technology really gaining time and quality over hand-drawing, scanning and illustrator digitizing : rather, I have seen a lot of time lost - undoubtedly due to poor process rather than an innate flaw, but it keeps happening. Management also tend to under-budget the real post-ex costs of digitising fom rectified photography, behaving as if the "technology" has already solved the problem - as if by magic - on site.
....................<snip>
Although I agree completely with your sentiments.......but
In surveying say a half-collapsed Bastle surrounded by enclosures and ridge and furrow rectified photography of wall elevations, scatters of stone rubble etc. digitising, and plotting of enclosures and R+F from aerial photography was a million times faster than doing it by hand! Although this does depend on the speed/skill and dedication of those doing the digitising.
Upland survey is also lots faster using aerial photography (I'm talking about google earth) as an aid to site identification/location and in defining the extent of areas of remains. Again a million times faster and often more accurate than plodding over the moor in the rain alone.
Though neither replace entirely the need for skilled eyes (and feet) on the site.
Posts: 1
Threads: 0
Joined: Apr 2010
27th April 2012, 12:44 PM
overseas Wrote:I would acquiese to RP for the cobbled surface probably
Why? At the end of the day someone's going to have to draw round all the rocks, why not do it on site where you can actually see what's going on? A good draughtsman (I assume there are some still kicking about) is always going to do a far better and more 'interpretive' drawing using the 'live' subject?
|
