Work is indeed being undertaken on this very issue. A system was demonstrated at CAA UK last year in southampton by Geoff Avern which accounted well for lense distortion in vertical site photographs using a simple approximation. This allowed the production of photo-mosaics of entire sites relatively quickly with good results. The hardware used was a little cumbersome as i recall...
As for replacing hand-drawn plans, this is a complex issue: The process of drawing is an interpretive process and the record made is different from a photograph. As such, these are two different types of record available to the archaeologist which can be used to record and convey different information. I have been working on a project which also looked at methods of handheld recording, but the preferred approach to recording involved digital drawing using CAD/GIS on-site rather than photography. This retains the idea of creating an interpretative record of the archaeology inherent in drawing rather than making an 'objective' record using a camera which can then be subsequently interpreted.
From a GIS point of view, relying on a series of vertical photos of a site as the primary plan record is problematic. Firstly, there is no way of attaching attribute data to spatial features requiring some level of digitisation of the features if this is to be achieved. Secondly, digitising features from the vertical photographs will introduce error into the data due to the lense distortion of the camera and potentially the method of georeferencing. Thirdly, any form of rubbersheeting or polynomial transformation applied to the images during georeferencing will affect their suitability for deriving measurements from.
>>> John Wood <[log in to unmask]> 06/01/2004 11:12:04 >>>
I have been interested in this topic for a number of years though know not
of any references for the subject.
I would expect however that soem form of computer manipulation would be
needed to counter lense distortion which has long been a problem with such
----- Original Message -----
From: "Paul Barford" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, January 06, 2004 5:44 AM
Subject: Vertical digital photographic recording
> Apologies for cross posting
> Is anyone on this list working on the use of on-site vertical digital
> photography coupled with graphics programs in on-site computers to create
> excavation documentation and in particular to replace hand-drawn layer and
> feature plans? Are there any published accounts of these recording systems
> and their efficiency and reliability ? What about drawbacks?
> I would be grateful for any information.
> Paul Barford
This e-mail is intended solely for the above-mentioned recipient
and it may contain confidential or privileged information. If you
have received it in error, please notify us immediately and delete
the e-mail. You must not copy, distribute, disclose or take any
action in reliance on it.
Telephone 020 7973 3000
Facsimile 020 7973 3001