How can we improve the Geophysics recording in OASIS?

The OASIS form started collecting extra information about Geophysical surveys in 2004 when The Royal Commission for Ancient and Historical Monuments in Scotland (now Historic Environment Scotland, HES) funded the creation of an extra part of the OASIS form.

How is the data collected now?

When a user selects Geophysical survey under project type they then see

Geophysical Survey of Proposed Solar Park, Collacott Farm, Fremington, North Devon (OASIS ID: archaeop1-197543)
Geophysical Survey of Proposed Solar Park, Collacott Farm, Fremington, North Devon (OASIS ID: archaeop1-197543)

an extra section to complete. These completed survey details are then passed on to relevant national body (HES or Historic England), HERs, other data consumers and entered into the Geophysical Survey Database (GSDB) so it can be seen publicly. If a report is added to the OASIS record then this is also linked to the record in the GSDB. The metadata entered in the OASIS form for a geophysical survey is sufficiently detailed to accompany a digital archive that is submitted and allows the data to be reused.

So the survey details are added once to the OASIS form and used in multiple places. This ‘COPE’ Capture Once Publish Everywhere is the driving aim of OASIS.

Attached (Geophysics_fields) is a list of the fields currently collected by OASIS and the accompanying pick lists that are available for some of the fields. People are able to enter other terms as well as those in the lists and this has created some problems on the transfer of data to the Geophysical survey database.

How can you help?

And here we get to the point of this blog… we are in the final phase of consulting interested parties and would like to hear what documentation and metadata you think is necessary to make geophysical data more useful and reusable.

The information collected by the form was originally defined by HES, through consultation with the geophysics community, with additional contributions by Wessex Archaeology for marine remote sensing techniques and most recently via GeoSIG and those working within the profession, and is closely related to the ADS’ Guides to Good Practice. However it has sometimes been criticised as too complicated. As digital archivists and other information technologists will confirm there is often a level of disagreement between archivists and data creators on the amount of metadata needed to describe an archive/project. It is a slight aside but this video illustrates this rather well.

Alternatively, are the fields collected correct and the issue more to do with whether the person completing the OASIS form is not the same person as did the survey and so does not have access to the required information?

Please have a look at this document (Geophysics_fields) listing the fields and pick lists currently used in the Geophysics section of OASIS and let us know any changes you think need to be made.

Solid and Drift Geology

At the moment this is collected using drop down lists and relies on the person filling in the form to know the geology. We propose that this would be assigned automatically using the project location to bring the correct geology from the 1:625, 000 Solid and Drift Geology maps of the United Kingdom by Web Mapping Service (WMS).

Another question concerns Survey Extents

The grid reference provided through OASIS locates the position of your survey grid(s), but hinders successful relocation of your survey subsequently.  The position and extent of the survey grid is a fundamental part of the recording process and this digital data is taken forward through to completion of the project report.  In Scotland we are interested in uploading these spatial footprints to help develop a spatial index for a range of remote sensing techniques.

Current recording practice © Crown copyright and database right 2016 Ordnance Survey
Current recording practice
© Crown copyright and database right 2016 Ordnance Survey

 

 

 

Proposed recording © Crown copyright and database right 2016 Ordnance Survey
Proposed recording
© Crown copyright and database right 2016 Ordnance Survey

So please leave us any comments on these issues in the section below, this is your chance to influence the development of the new OASIS form.

 

10 thoughts on “How can we improve the Geophysics recording in OASIS?

  1. Dear Jo
    Magnetometry is the most used technique, probably 97% by area. You can find out as you are able to query the metadata, I and others who submit it aren’t allowed to ( unless I have missed something).
    It’s results are almost entirely geology dependent. Gault clay and some red sandstones produce duff results. This can be used by the unscrupulous to argue that there is nothing there of interest.
    It would be good of we could all select the surveys on the basis of geology.
    The geology map only has even drift deposits if they are over a metre or so deep. They miss the loess/brickearth/supranatural so a means of allowing additional input from the excavators would be useful.
    I tried to find a survey in Drayton parish today. It gave me all the work in all the Draytons as I couldn’t additionally select by County.
    Also the picture which accompanied the blog was by ArchaeoPhysica. I gather that they have gone into administration and their directors now trade as Tigergeo. ArchaeoPhysica in their blurb say they do many hectares of survey, but how many are on the ADS? That’s the nature of the problem.

    1. Given that most of our work is confidential, and remains so, it is hardly surprising that many of our (1000’s) hectares of survey are not on the ADS. We do however use OASIS for some projects so its not as if all the work remains hidden forever.
      What exactly then is the problem that you refer to?

  2. Suggesting one particular geology or other is ‘duff’ with regard to magnetometry is simplistic. There are many other factors to consider, the ‘hang-up’ over geology is outdated as attested by the many thousands of hectares of survey carried out across the country. Magnetic contrast exists within the soil and of course this relates to the parent geology but there are a range of factors to consider. Hydrology, organic composition, land use, contaminants and the nature and type of archaeological deposits present to name a few. So one has a range of considerations each one of which may be the dominant factor in predicting the outcome of a survey. After carrying out some 2000 separate surveys across most geologies in the UK, with the exception of some sandy heathlands experience has demonstrated the presence of magnetic contrast relating to ‘cut’ features within all of them. Subsequent intrusive works proves their archaeological potential or not and how representative the results of the survey may be – sometimes just one faint mark is all that is needed to locate the presence of an important site.

    Gault clay can produce excellent results

    1. Very true. It is not universally possible to link a particular geological unit with the magnetic properties of the surface soils. A case in point are the sandstones across central England where magnetic contrast varies even where the bedrock unit is the same. Superficial deposits, hydrology and land use are all major factors as all influence the soil chemistry.

  3. The majority of survey work is not carried out on a fixed grid. For mag, GPR and res a significant amount of survey is now carried out with GNSS systems and is effectively randomised data. For a number of UK companies all mag work has been randomised for quite a few years, so data is tagged with ETRS89 or similar positional data from the GNSS and this has to be converted to derive OS coordinates which have a much lower level of accuracy, and with most archaeological units then uploading mapped anomalies back to a GNSS to target features then there is a conversion back to ETRS89! This does not seem efficient. Is the proposed new grid system referencing the corners of a block of grids or is it allowing input of a dxf/dwg/shp file showing a polygon of the survey area?

    Badvoc

  4. ADS Guide to Good Practice is outdated and was written without consultation with commercial ops. It was written for universities doing research and is not a good document on which to base OASIS. All current guidelines are too out of date. The whole debacle with data archiving is a case in point of ADS not bothering to ask or listen to commercial ops. How is this being done? You mention Wessex and GeoSIG, I thought the latter was defunct. There should be proper consultation with all commercial operators.

    B

    1. Who has mentioned Wessex and GeoSIG? I’m not seeing messages with these in in the thread that is publically visible. Thanks

  5. Badvoc – It’s completely untrue to say that the guide was written without consultation with commercial units. Prior to the publication of the revised Geophysics guide, ADS ran a workshop (9th Nov. 2010) in order to gain feedback on the contents of the new guide. Over twenty invitations were sent out to a range of interested parties (including commercial units and GeoSIG) with the aim of engaging and incorporating feedback into the new guide.

    Additionally, a (apparently not defunct) CIfA GeoSIG/ADS workshop has recently taken place (27th Nov 2015) in order to gain input from the community and inform ADS archiving policy and procedure. In both cases, the contribution of comments, etc. has not been limited to ‘attendance on the day’.

    While I’ll admit that elements of the Guides inevitably become outdated – and geophysics is an area that seems to develop quickly – it is not through ADS “bothering to ask or listen to commercial ops.”

  6. Hi Kieron

    Do you have a list of those specialist geophysical companies who attended in 2010 and why only 20 invites were sent? Have you asked whether GeoSIG actually requested comment from its membership in 2010? Many people heard nothing of this and yet again in the last couple of years we’ve had really badly thought out archiving requirements foisted onto the sector because nobody in ADS thought about asking the commercial geophysical operators about the size of sites or the amount of data collected. The approach has been ‘it’s fine just milk the developer for the resources’. Not acceptable.

  7. Thanks for all the comments so far, but I think some of them have gone rather off topic – the questions being asked here are whether the fields collected by the OASIS form are collecting the correct data to be passed on to HERs and national bodies interested in what archaeological events have occurred in the UK.

    If you would like to discuss how geophysics is archived with the ADS it would be best to contact our Collections Development Manager Louisa Matthews at louisa.matthews@york.ac.uk.

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