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"I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail". - Abraham Maslow Drawing similarity from this well-known quote, it can be tempting to maintain your teams current survey industry knowledge whilst also remaining to use the same ‘tools’ for the job (or in this case, which surveys are used on your projects). But, if the ‘nail’ in this scenario represents your project, then surely it would wise to understand the right ‘tool’? In this example the correct survey methodology, which you and your team need for your projects? What’s more, when there are ever evolving survey techniques, surely, it’s wise to keep up to date with these new developments? That way you are able to reap the benefits of innovative survey offerings. The SUMO Group is proud to offer its industry-leading Measured Building survey knowledge. We offer this through a wide range of free technical presentations, available to both existing clients and non-clients. Our Measured Building survey presentations can cover the survey industry in general, but can also be focused on specific survey methodologies. For example, Laser scanning & Revit modelling and how these can be applied in practice. SUMO Technical Awareness Presentations give you: Better safety understanding Improved efficiency The best ways to achieve cost-savings Who would a Measured building presentation suit? We tailor our presentations to suit and be of interest to a wide range of audiences. This could include Directors and Senior Managers; Site Agents and Operatives; Health and Safety Advisers; Planners and Design Engineers; Entry level staff. When can SUMO come in? With a commitment to bettering our client’s survey knowledge, we will always aim to accommodate your preferred presentation time and date. Our presentations are designed to fit into your working day and can be easily created into a ‘Lunch & Learn’. Where are they held? Presentations can be held in your offices, on-site, or at our Head Office in Havant. What is the cost? SUMO’s technical awareness presentations are FREE to all our clients, their sub-contractors as well as non-clients.

Let’s be honest, everyone likes to make a saving on their budget. So, when you’re faced with the decision to commission your site’s utility and/or topographic survey, wouldn’t it be handy to know that there’s a hassle-free solution that comes with up to 50% off the cost? Well, SUMO has done the number crunching and presents its handy ‘one-stop-shop’ survey approach by combining its popular utility and topographic services. So, what am I getting from SUMO? It’s simple, our clients are getting a full topographic survey and full utility survey, all wrapped into one. You’ll receive a high-quality digital deliverable to industry standards. What’s more, any survey that is commissioned receives a whole host of additional benefits such as: Fast Response from 1st enquiry to quotation Rapid turnaround of final drawings Complimentary on-site survey debrief from one of our trained surveyors The opportunity to arrange a free training presentation which can enhance knowledge for future projects and counts towards your CPD requirement. What equipment is used for a utility and topographic survey? We have invested in a range of industry-leading equipment including Dual Frequency Ground Penetrating Radar (GPR) systems. This equipment can locate both small shallow anomalies and larger features at depth, without the need to use two separate GPR systems, which may double the time spent collecting the data. What's more, such systems allow our surveyors to work in real time, so the location of utilities can be marked on the ground for immediate use, as well as being recorded on your survey drawing. In addition, the system can also collect data for post-processing, allowing more complex features to be identified. Another workhorse for the surveyors is the cable and pipe locator, a technique that we call Electromagnetic Location (EML). We have worked closely with the manufacturers over the last 15 years and always strive to keep up-to-date with the latest systems. We currently use an advanced high-precision cable locator containing a unique arrangement of 5 custom-manufactured, precision-ground antennas. It allows our surveyors to choose the best method to locate specific pipes and cables. Of course, we also utilise various Robotic Total Stations for the topographic elements of the job, including high accuracy units for control and monitoring works. GPS is also used to provide positioning to the Ordnance Survey Grid and Datum at the push of a button. How does SUMO crunch the cost? SUMO’s utility surveys utilise an element of topographic work as standard, irrespective of whether you commission any topographic work. This is because we supply all our clients with a basic record of the physical features of the site area (such as Kerb lines and buildings) which can be used to reference the overlaid utility information. As the basic topographical features will already have been mapped to be able to reference the utility survey data, it is a simple case of surveying the additional features to make up the full topographic drawing. You could see it as a topographic ‘top-up’! In addition to this, SUMO has invested a lot of time cross-training our surveyors to ensure that they are multi-disciplined. Rather than having separate surveyors trained in each field, every SUMO surveyor can undertake a range of different surveys. We also have surveyors based strategically throughout the UK, meaning that we can respond quickly to urgent requests anywhere in the country. This also means that our surveyors are truly local to your site. This carefully developed flexibility allows us to undertake a combination of survey methodologies on the same site, reduce costs associated with travel and all in all, making our service even more competitive.

A comprehensive utility survey carefully developed and refined over 15 years by industry leaders. The SUMO Survey is for clients who need consistent results and high levels of detection accuracy. We assessed the equipment and methodology to discuss the depth of penetration achievable… What is the SUMO Survey? With growing infrastructure, there could be hundreds of utilities lying right beneath our feet. Accidental strikes can cause project delays, incur substantial costs and create negative PR. It is important to identify and map such utilities, either at the design stage, or in advance of breaking ground. If your employees are going to break ground, you ought to have a utility survey done to protect them. This is often written into the Health and Safety Guidelines for most projects. Utilising the latest non-invasive technology, the SUMO Survey dramatically reduces the high-risks of hitting buried utilities and the associated cost of repairs. It combines 3 key survey techniques and is a highly effective utility survey. Another great feature of the SUMO Survey, is that Topographic survey techniques can integrate into the survey process. As well as the 'basic' utility mark, we can also provide you with full Topographic drawings of the data. What equipment is used and how low can SUMO go? We have invested in a range of industry-leading equipment including Single, Dual and Multi Frequency Ground Penetrating Radar systems. This means that we can locate both shallow and deep features, without the need to use separate GPR systems. This would increase the time spent collecting the data and the cost considerably. Using a 300/800 MHz antenna for example, we have the capacity to locate conventional utilities buried to a depth of 1-1.5m. If ground conditions are suitable, we can locate deeper features up to approximately 7m. Such systems also allow our surveyors to work in real time. This means that we can mark-out features as we go, and also collect radar data for post-processing, allowing for more detailed examination of more complicated sites or discrete features. Another workhorse for our surveyors is the Cable and Pipe Locator. We have worked closely with the manufacturers over the last 15 years and always strive to keep up-to-date with the latest systems. We currently use an advanced high-precision cable locator containing a unique arrangement of 5 custom-manufactured, precision-ground antennas. It allows our surveyors to choose the best method to locate specific pipes and cables. We also utilise various Robotic Total Stations. This includes high accuracy units for control and monitoring works and lesser instruments for general surveys. High accuracy GPS is also used to provide positioning (within 30mm) to the Ordnance Survey Grid and Datum at the push of a button. Is there anything that can affect the depth of penetration? There are some limitations to the individual techniques that make up the SUMO Survey. This includes: Debris and uneven ground surfaces can affect the depth of penetration of the survey equipment. In extreme cases, it can also make the survey impossible to complete. This is because the conditions don’t allow for the correct penetration or accuracy of the survey equipment. Waterlogged ground surfaces can also interfere with the depth of penetration. Ideally, ground surfaces should be dry, but this isn’t always achievable due to UK weather! Similarly, ground that contains high levels of clay can become difficult to survey as the equipment signals cannot easily penetrate this material. Completely clay ground can be near impossible to survey using GPR. It is often reliant on other survey techniques to trace underground infrastructure. SUMO clients needn’t worry though, we will always make our clients aware of potential limitations caused by the site conditions. We will always work with them to achieve the best possible survey data. Why should you use SUMO? With over 15 years’ experience, we pride our survey offering on the following: We employ many of the industry’s leading survey professionals. Each of our surveyors is trained in various survey techniques to aid flexibility and tailoring of our services. We aim to provide each client with the complete SUMO customer experience. Because of our unique size and nationwide coverage, we can tailor each project to a client’s individual needs and budget.

For many of SUMO’s clients, it is an internal requirement for most projects, that they obtain a PAS 128 compliant survey. In practice, there are many ways of achieving this, but we often hear that “PAS 128 compliancy comes at a cost”. So we got together with SUMO’s industry leading professionals to discuss PAS 128 and concluded that it’s easy to be cost-effective, if you do it smart! Keep reading to find out more… So, what is PAS 128? PAS 128:2014 is the latest specification for underground utility detection. The purpose of the PAS 128 specification is to set out the accuracy to which survey data is captured. The quality expected from the data and the confidence in the data is highlighted. Although, it is not relevant for all utility surveys, where it is appropriate to specify a PAS 128 survey. There will be benefits for the client, the practitioner and the general public. The specification covers: The project planning and scoping process. The classification system for quality levels based on the survey category type, the location accuracy, the need for post-processing and the level of supporting data. Desktop utility records search. Detection. Verification. Location. Deliverables. As a result, PAS 128 provides a strong procedure for delivering quality utility surveys in the UK. There are four Survey Category Types They are referred to in the specification and each one focuses on levels of precision specified in an underground utility survey that is PAS 128 compliant. Why was PAS 128 needed? To combat the inconsistent costs and service levels prevalent across the utility survey industry. To highlight inferior data being provided by inexperienced surveyors. Inaccurate data on the existence and location of utility assets can be detrimental to a projects smooth running. A lack of reliable information during the design and construction phase can also result in expensive errors. At the same time, the safety of workers and the public can be put at risk, as well as many other needless problems. It is vital that accurate information for the location of underground utilities is available. Accurate mapping of utility networks also helps to improve asset modelling capabilities with more resolute outcomes. The benefits of PAS 128 ensure a high level of accuracy and certainty of the results for each utility detection survey. This increased accuracy and reliability of information provided to the client, then enables them to plan effectively for all utility-based activities. So, how do I keep costs low whilst obtaining sufficient survey data? The specification is actually written for practitioners to adhere to. Clients then specify the survey type and quality level they need. Your survey provider should help you to determine the most appropriate survey intensity. It all starts with understanding the hierarchical approach PAS 128 has to the production of utility surveys. There are four survey quality levels which the client can specify: A through to D. Two technical directors at the SUMO Group were appointed to the Drafting Panel and the Steering Group by ICE and BSI to assist with the writing of the original PAS 128: 2014 specification. The guiding role that SUMO played in the creation process; means that we have an in-depth understanding of how PAS 128 works. This means that SUMO can also identify the best and most economical approach to applying PAS 128 certified survey options to your site and budgetary needs. At SUMO we understand that many client’s commissioning a survey are obligated by ‘higher powers’ to specify a PAS 128 compliant survey. But, the relevance of methodologies can be easily misunderstood. We are often (mistakenly, in our opinion) asked for the highest and most costly quality level of PAS 128 survey to be completed throughout a site. It is a common misconception that by asking for the highest-level survey, you will receive the best survey. In fact, in most cases this isn't actually the best approach. Asking for the highest quality level of PAS 128 may be too intensive for your specific site area and could also needlessly raise your survey costs. The key point to recognise, is that the PAS 128 specification was written to allow for the survey area to be subdivided. This is so that various and appropriate levels of PAS 128 survey can be applied to different areas. Referencing the quality level tables above means that we can satisfy a projects needs whilst also addressing safety and financial requirements with varying quality levels and relative costs. “I need an M4P PAS 128 survey; because it’s the best” Yes, it is the most intensive PAS 128 survey option. But, it may not be the best solution for your specific site. “Tell me why” Your site is predominantly open greenfield and only partly tarmac car park. So, this may not require the intensive survey grid used in an M4P survey across the entire site. Conducting an M4P survey throughout this specific site will also take longer to survey and will cost considerably more. In this case, an M1P survey for the greenfield space and an M2P survey for the carpark may be the best solution. It will still be fully PAS 128 compliant, plus it will also be considerably cheaper than a full M4P survey! Above: Example of varying Levels of PAS 128 being applied to a site area. Notice how the most intensive PAS 128 levels have been concentrated in areas where typically lots of utilities are found; such as around the buildings. A less intensive PAS 128 quality level has been applied to the field areas. In doing this, you can still obtain sufficient survey data at a fraction of the cost. In summary… PAS 128 is setting the standards within the survey industry. Survey providers offering PAS 128 compliancy must adhere to these specifications and standards. As a consequence, you can be certain that with PAS 128 you're getting the most assured standard of survey for your money. The comparison of different supplier quotes should also be much easier. This is because all compliant quotes should be based on a comparable methodology. Having a brief understanding of PAS 128 whilst commissioning your survey will also ensure the best chance of maximising your budget. Any quality survey provider which offers PAS 128 compliancy such as SUMO, should be willing to discuss, agree and scope the survey with you. Unfortunately however, in our view, PAS 128 does not provide enough client guidance in practice, on commissioning a survey. Especially as clients have a defined role in the PAS 128 survey process. A review of the existing PAS is about to get underway (which SUMO will be involved with) and will focus on adding extra informative sections to improve guidance to clients and to achieve better clarity. In the meantime, SUMO has put together an easy to understand Client Introduction to PAS 128: 2014. This should start you off in the right direction!

July 8, 2019 The SUMO Group has 139 years of combined survey experience, consistently aiming to reach the highest level of survey quality and customer expectations. But, in our experience, many clients are wasting their time and money through their choice of survey provider. They often return to SUMO to help resolve subsequent survey issues. To avoid this problem, we’ve put together this Ultimate Guide to Choosing Your Survey Provider, to equip you with the best knowledge when approaching a potential surveyor. Any survey provider worth their salt will have the following attributes: Full professional and commercial licenses to carry out survey work within the UK. The Survey Association (TSA) membership Accreditations including CHAS and Constructionline. Surveyors will hold CSCS cards Up-to-date DBS checks to work on certain projects such as schools or care homes. Appropriate insurances for commercial purposes, with suitable levels of cover. As well as professional indemnity insurance If you have any reservations about any of the above, then ask your survey provider to see documented proof of these attributes. Any quality survey practice will be more than happy to reassure you with documented evidence. SUMO has seen it all… By employing a diverse range of talent (in our opinion, some of the best in the industry) over our many years of commercial experience, we have seen our fair share of clients returning to SUMO after experiencing ‘survey disasters’ elsewhere. Whether the client was misinformed about the company they used, or the surveyor simply couldn’t work to the high standards that expected. Here are some of the problems/typical quotes that SUMO hears of when clients return to us: “The water and gas pipes weren’t detected”. In practice, it is actually very difficult to trace water and gas pipes. Especially with the popularity of plastic piping increasing. This is because Electromagnetic Location (EML), which is typically used to trace pipes and cables are rendered ineffective when attempting to identify plastic water and gas pipes. To overcome this problem, SUMO uses Ground Penetrating Radar (GPR). Many competitors don’t use it. “Invert levels were not detailed”. This is the measurement to the bottom of the out-flowing pipe within a manhole, which SUMO always measures when a manhole is inspected. “Low-quality drawings”. SUMO prides itself on producing the highest quality, multi-layered drawings, for ease of client understanding. “Utility survey techniques were used in isolation with unclear results”. SUMO understands the limitations of individual methodologies and has developed the SUMO survey with multi-disciplined survey techniques. This equals a comprehensive utility survey service, which provides greater clarity. "I paid more than the price I was quoted”. It is our experience that clients are often hit with unexpected additional costs. SUMO has worked hard with its in-house contracts team to ensure that the price quoted, is the price that you pay. “Lack of experience”. Of course, this is something that can only be gained over time. SUMO has the advantage of 139 years combined survey experience. SUMO employs some of the industry’s leading talent, each with many years of respective survey experience. “I don’t think the completed survey is PAS 128 complaint, despite requesting for PAS 128”. SUMO helped to co-author the PAS 128 specification and therefore is extremely knowledgeable about the specification and how to adjust the various levels of PAS 128 to suit client’s projects and needs. Often clients return to SUMO asking for the PAS 128 compliancy that they thought they would originally obtain. Alternative survey providers can simply lack the expert knowledge needed to deliver PAS 128 compliance. “The survey didn’t meet my expectations”. It is our experience that many clients are promised ‘all bells and whistles’ when this may not be achievable on a site. At SUMO, we aim to be honest with our clients about the limitations of the survey techniques that can be used. Over the years, we have learnt that managing client expectations is the key to happy customers. This means everyone’s expectations are carefully met. What should you do if you are not happy with the survey provided to you by your current supplier? Always contact your survey provider if you are unhappy with, or unsure about any elements of your survey deliverable. Any professional surveyor will be able to explain their survey deliverable to you in a manner that avoids confusion. They can also deal with any issues that have arisen. If this cannot be resolved, then it may be time to look elsewhere… Why should you consider working with SUMO? We are committed to maintaining the highest possible standards in all aspects of surveying. We pride ourselves on providing a survey solution that is individually tailored to your needs. We use our extensive experience to support you throughout the entire life-cycle of a project, from concept, planning, design, construction to completion.

In the UK, badgers are a protected species under the Protection of Badgers Act 1992. This act makes it illegal to take, injure, kill or or be cruel to badgers. It also prohibits human interference with badger setts. This can present a big issue to clients who are hoping to dig for archaeology or have plans to develop an area of land. It is important to consider the potential impact on badgers before any work is undertaken on a site. Especially if the site is greenfield, where it is likely that badger setts will be present. Above: Entrance to a badger sett discovered by SUMO Geophysics. Where to start… If the presence of badgers on your site is unknown, then your first point of contact is likely to be an ecological adviser. They can establish whether there are visible ‘clues’ consistent with badger activity. If there is a presence of badgers on your site, then further investigation may be advisable. If the habitation of badgers is already established, then it may be unnecessary to consult an ecological adviser. Instead, you may wish to investigate further to gauge the extent of the sett and its location. Getting your badger sett survey… Mapping the entrances of the badger sett can give you a basic understanding of the area taken. But, to further understand the badger sett you will need a geophysical survey. This will give you information about the central nest, tunnel layout and the depth of the tunnels. Above: This image shows the large size that badgers may dig their tunnels to. To put this photo in perspective, a small child could stand straight in these tunnels! The tunnels are often large, so they show similar characteristics to voids. This means that the same equipment used for the location of voids can be adapted for badger sett surveys. Ground Penetrating Radar (GPR) is ideal for mapping the location and extent of setts. Above left: Example time-slice detail of the site showing the tunnel layout of the sett. There are three entrances located on the right-hand side of this image. Above right: Example interpretation showing the extent of badger sett a badger sett on site. Why should you contact SUMO? SUMO Geophysics has over 40 years of experience at the forefront of archaeology. Our geophysics team provides a comprehensive customer experience from start to finish. Working to tight schedules and deadlines, SUMO Geophysics prides itself on being the largest provider of professional geophysics in the UK with Nationwide coverage.

Geological and buried manmade features or objects can cause local variations in the earth’s magnetic field, which can be measured with a magnetometer. Accordingly, a detailed magnetic survey can be used to effectively define areas of past human activity and it is a quick, cost effective technique. As such, it has become the industry standard for archaeological surveys. However to obtain successful results from your archaeological (magnetometer) survey, several factors must first be taken into consideration. The most important is the nature of the ground conditions, especially when there are crops growing on the fields. We have therefore set out below, a list of the perfect conditions for geophysics to help you get the most out of your archaeological survey. In an ideal world, all survey sites would have the following ground conditions: - 1. Short pasture, or early season crops 2. ‘Stubble’ - short crops after the harvest 3. Lightly ploughed fields Lightly ploughed fields which have been prepared for crops can be easily surveyed. But, if the plough is deep or the field contains clay soils, then it can become tricky or even impossible to survey. So, what ground conditions are unsuitable for archaeological surveys? Factors affecting the magnetic survey may include soil type, local geology, previous human activity, disturbance from modern services etc. The physical state of the ground itself can also significantly affect the result of the survey, especially rough or uneven surfaces. SUMO understands that the ‘perfect’ survey conditions will rarely be achievable due to the nature of individual sites, but we have listed examples of unsuitable ground conditions for archaeological surveys below: 1. Old potatoes fields/ Oilseed rape fields 2. Overgrown sites 3. Potato fields 4. Untidy, dumped material Are there other factors which affect the carrying out of magnetometer surveys? Livestock - for safety purposes, livestock should be removed from survey areas. Agricultural work i.e. certain crop sprays can make fields unsafe for personnel to survey. Above: Magnetic survey equipment which can either be towed by a quad bike (where conditions allow) enabling large amounts of data to be collected quickly, or man powered, which is somewhat slower!  Smaller two sensor arrays which can be carried by an individual are also used in less open sites. SUMO will always discuss the survey area with its clients to understand its current use and to tailor its approach wherever possible. Most archaeological surveys are carried out using magnetometry but Ground Penetrating Radar (GPR) is being employed more often. While the same ground conditions apply for GPR as they do for magnetic survey, there are a couple of other issues which need to be considered. Clay or clayey soils can severely restrict the use of GPR in that the energy waves cannot penetrate through dense soil structure. A high water-table will also limit the depth of penetration. Above: Ground Penetrating Radar (GPR) equipment. Seasonal factors can also affect geophysics surveys both positively and negatively… The spring months: Early spring is an ideal time for a survey, when the weather is improving and the land is drier, but before the crops have grown significantly. New crops can be delicate and severely impacted by either cart systems or trampling under foot which can result in the landowner being unwilling to authorise a survey until the crop has matured or even been harvested. The summer months: Tall crops can interfere with magnetometer sensors. This can make it impossible for the operator to walk safely. Maize fields are the worst! This is because despite the harvest, the remaining stalks can be extremely brittle. This causes problems for the surveyors walking the site. It is impossible to collect underground GPR mapping data in potato fields. Other root crops are less of a concern unless the ground is heavily rutted. The summer is also an ideal time for aerial surveys, when archaeological features can often be seen as a result of the differing moisture contents between archaeological remains and the surrounding land. The autumn months: Immediately after harvest is a perfect time for a survey, when the land is dry and the weather is good. Why should you use SUMO? With over 40 years’ experience at the forefront of geophysics, we pride our survey offering on the following: We employ many of the industry’s leading survey professionals. All our surveyors are multi-skilled to aid flexibility and tailoring of our services. Our unique size and nationwide coverage allows us to tailor our service to a client’s individual needs and budget. So, beat the rush, get your order in early and don’t let your competitors get that all important survey slot!

This article looks at the depth be low the ground surface that archaeological features can be detected using magnetometry and ground penetrating radar (GPR). Above: This image shows cart-based magnetometry equipment used for archaeological surveys. The vertical ‘poles’ are sensors which detect small variations in magnetism. What equipment is used? Magnetometer… The main workhorse of geophysical surveys is the magnetometer. These can be cart-based (pictured above) which are tracked by GPS or handheld (pictured below) in which the surveyors walk at a constant pace within GPS established survey grids. The sensors are very sensitive – a pit may produce a magnetic anomaly as small as 1-2 units compared to the earth’s magnetism of 48,000 units. Thus, archaeological features which have stronger magnetic content can be detected to greater depths. For example, pottery kilns can result in magnetic fields measuring a few 100 units in strength and along with tile and brick kilns can be detected at greater depths. Ferrous objects have the strongest magnetic fields because of their metallic contents. So, a buried oil drum or UXO (with a large ferrous component) can be detected at depths of say 1m to 2m. An old Ford Cortina car may even be detected beneath 5m to 10m... although why you would bury one at these depths would be questionable! Magnetometry can, however, be useful to detect crashed aeroplanes. It should be noted that it is difficult to gauge the actual depth of a feature based on a magnetic survey alone; in order to get the best estimate of depth, GPR can be employed to investigate a magnetic anomaly, as shown in the example below. Above left: This image shows a strong magnetic anomaly (in red). Above middle: Next, the same magnetometry data are presented as an XY trace (showing the full strength of the response). The red line shows the location of the radar transect depicted to the right. Above right: This image shows a radar transect – a vertical slice through the ground giving an indication of depth. Above left: The excavation of the feature and a camera being inserted through a small hole which opened at the surface. Above right: This photograph shows the detected feature as an intact medieval tile kiln. The floor is at a depth of some 2m below the ground. Ground Penetrating Radar (GPR)… The second workhorse of geophysical surveys is Ground Penetrating Radar (GPR) equipment. Again, this equipment can be either pushed across the site or towed using vehicles. Above: GPR equipment being towed and being manually pushed. GPR works by pulsing electromagnetic waves into the ground. It identifies the depth and density of buried objects by measuring the strength and time delay of returning signals. With various applications to be used, including greenfield and brownfield sites, there are no real 'hard and fast rules'. The choice of the best equipment is determined by the surveyor, dependant upon what the client hopes to find, as well as the size of the survey area. Typically, SUMO uses High-Density Ground Penetrating Radar equipment to collect as much detail as possible. This is used on sites such as Scheduled Monuments and research projects. When looking for very shallow features (such as rebar) or very deep features (such as Victorian drainage pipes) we use a single channel GPR system with an appropriate antenna. Mid-range features would see us use a High Density or Dual Frequency antenna. We research as much as we can about the site, its history and what we are looking for to aid with this decision. Above: This is an example of 3D data collected by Ground Penetrating Radar (GPR) equipment. It was an ideal technique for this site in which the aim was to trace the outline of a Roman Villa.

It is a well recognised fact that trenching can be both an expensive and a ‘hit-and-miss’ method to assess the potential archaeology on a site. We therefore asked SUMO's resident geophysical survey expert Dr John Gater, how clients can save their time and money using geophysical surveys? So, tell us how geophysical surveys can work in conjunction with trenching? Normally, geophysical surveys are part of a staged approach to assess both the extent and nature of any archaeological remains on a site. This would usually be before development. The survey work is often carried out alongside (or after) a Desk-Based Assessment (DBA). This looks at existing site records, old photographs, museum archives, past excavations and fieldwalking exercises. The DBA and the geophysics surveys can then provide an assessment of the potential archaeology present, before test trenching. Trenching is an expensive exercise. Especially if carried out 'blind' and digging sample trenches over a site without first referencing known features or geophysical anomalies, is arguably, an inefficient way for clients to proceed. If archaeology is then found in the random test trenches, it is often necessary to investigate further, incurring yet more costs. At SUMO, we believe that it is far quicker and cost-effective to complete the geophysical survey work before test trenching commences. SUMO target anomalies identified using the geophysics data, thereby focusing the test trenching. With this approach, a 2% sample may be sufficient, opposed to the more normal 5% sample of trenching, thereby saving significant costs. The images below are an example of excavation based on geophysical survey data: Mosaic – resistance survey showing a Roman villa. The red circle shows the area where the trial trench was located. The villa has two wings - in the top right of the data image the rooms and corridors are visible and the indications are that the floors are simply beaten earth between stone / flint walls. By contrast, the wing on the left of the plot shows ‘solid’ floors – and these proved to be intact mosaics, albeit damaged by recent ploughing. Kiln – the magnetic data plot shows a small Romano-British settlement, comprising individual land parcels (for workshops, houses and shops) separated by tracks and roadways. The stronger magnetic anomalies (‘blobs’) indicate large rubbish tips, quarry pits and small industrial features. A classic ‘kiln-like’ anomaly was selected for excavation as it was hoped any associated pottery would provide a date for the settlement; it was exciting to see a small intact kiln structure surviving below the turf. Can you explain how geophysics can save clients both time and money? Most of the time, clients can save time and money by trenching a smaller targeted % sample. Occasionally, archaeological units argue that when topsoil is stripped (as part of the development work), any archaeology found can be dealt with at that time. But, this approach means that if a ‘major’ archaeological discovery emerges at this late stage, then extra resources will have to deal with that archaeology. This would cost yet more time and money. If a geophysics survey is carried out in advance of the site work, then the extent and nature of the potential archaeology can be understood. Contingencies can be put in place to maintain efficiency and avoid unnecessary additional costs. For example, potential archaeology identified by the geophysics survey can be dealt with in advance of any site work by selected excavation or by redesigning the site plans, so that core areas of archaeology can be left undisturbed and preserved. The fact that geophysical surveys are much cheaper than excavation, means that they can save developers large sums of money ahead of site works. How has geophysics advanced to allow for time and cost savings? In the past, geophysical surveys used sample areas only. But as technology advanced, it became the norm for complete site surveys to be undertaken. Looking to the future, we may see surveys return to a more selective sample of areas. This could be with further evaluation of key areas of interest being undertaken with a second geophysical technique to further identify any potential archaeology. For example, a Ground Penetrating Radar (GPR) survey could follow the completion of a magnetic survey. The magnetometry data can define key interest areas such as building outlines, following which the GPR could be used to provide detailed plans and depth information about buried structures. See example below: Above: Example of magnetometry data. This survey technique was used to locate areas of interest at Brancaster Roman Fort. Above: Example of Ground Penetrating Radar (GPR) data collected across Brancaster Roman Fort. The areas which were surveyed using GPR were informed by the magnetic survey data (pictured above). Above: This image shows the GPR data from Brancaster Roman Fort overlaid onto the magnetometry data. The correlation between the selected GPR survey area and the larger magnetic survey data can be clearly seen here. So remember, if you are planning to develop a greenfield site and want to avoid unnecessary trenching work, with potential site delays and increased costs associated with areas of potential archaeology, then contact us today to discuss your survey requirements further:

At SUMO we are lucky enough to have staff with an eclectic taste in television! Whilst watching a box set of Criminal Minds from 2006, one of our Directors was surprised to see the forensic team using Ground Penetrating Radar (GPR) equipment to locate human remains under a garden gazebo. With an extremely clear (and somewhat fanciful) data image, it got us thinking about the rise of GPR in clandestine investigations... Above: The above ‘data image’ was apparently collected by Ground Penetrating Radar (GPR) on the hit TV show Criminal Minds. Similarly, several years ago, another SUMO Director was watching CSI New York and spotted the exact same GPR equipment that SUMO regularly used for commercial survey work. Above left: The circled equipment is the GSSI SIR 3000 with a 400 MHz antenna. SUMO used to use this equipment daily but has since updated its equipment with dual and multi frequency GPR systems. Above right: SUMO’s GSSI Sir 3000 on a commercial site. During the CSI New York episode, not only did the GPR equipment ‘beep’ upon locating the body, but it also detected all the bones within the skeleton and identified that the victim was covering their face to defend themselves. Thus, the CSI team concluded that the victim had been murdered! Above: The image above shows the data collected in an episode of CSI New York. Whilst the equipment used was ‘state of the art’ at the time, the data in the programme was so detailed (it even showed individual bones, which sadly isn’t the reality! No wonder it took so long to find Richard III’s remains in the car park in Leicester…. we were obviously using the wrong equipment and should have borrowed Hollywood’s! The reality As exciting, glamorous and easy as Hollywood makes the survey process look, the reality is very different. When using GPR to locate buried bodies, surveyors look for a subtle change in the data compared to the surroundings. Often, buried remains present similar characteristics to air voids. If remains have been buried in a coffin or submerged in concrete, they can be more easily identified. This is because bodies which lay in concrete and within coffins appears as a ‘blob’ in the data (see image below). Above: The image shows a GPR Radargram ‘time-slice’. This is a vertical cross-section of data showing various coffin burials. We’ve discussed remains that are in a 'flat' position… but what happens if remains are crouched, upright or have been placed in a hole which has been backfilled with the same material? Often, clandestine burials are in a hole which has been quickly dug and backfilled with the same material (e.g. soils). This means it can be extremely difficult to identify ‘graves’ from the surrounding material. GPR does have its use in criminal investigations. Both the MET Police and the Home Offices use sophisticated GPR systems to locate clandestine remains. But in most cases, GPR is often used in conjunction with cadaver dogs, criminal intelligence, historic mapping and criminal profiling. Furthermore, SUMO also has previous involvement in several forensic investigations. Most notably, as a part of the search for ‘The Disappeared’ alongside the Independent Commission for the Location of Victim Remains (ICLVR) in Ireland. Fact versus Fiction As entertaining as crime investigation programmes are, they do little for the Surveyor industry. In fact, they can mislead people into thinking that GPR is an ‘X-ray’ machine, with the result. This means that clients may be disappointed by the actual results versus what they have seen on television. At SUMO it is our aim to consistently deliver the highest quality of data. It is important to manage our client’s expectations by explaining the limitations of individual survey techniques. As well as this, we will ensure the best approach for their specific project and what outcome they can expect.. We also work with our clients to gain as much site information as possible. This helps us to deploy the best equipment for the job and to make informed interpretations of the data. Want to know more about our survey techniques and their applications? Why not ask us in for a FREE, no-obligation technical presentation? You’ll get an honest insight into the world of surveying and we might even throw in a few Hollywood examples for fun!

Gone are the ‘old’ days where surveyors precariously balanced on surrounding items such as furniture to measure over the top of wardrobes, or put themselves at risk to measure awkward features at the top of buildings. The beauty of modern survey techniques such as laser scanning, is that if a surveyor can see it, then they can measure it using precise survey technology… Above: Gone are the ‘old’ days where surveyors precariously balanced on surrounding items such as furniture in order to capture measurements. Laser scanning allows us to manage workloads at the press of a button. Survey technology has advanced so much that we can press start and within 2 minutes, the equipment has measured 11 million points (which is probably 10,999,980 more than we need!) and the surveyor hasn’t moved a thing. Above: FARO Focus Laser Scanner working on a site. Laser scanning easily measures areas that are visable. But what about survey areas that a surveyor can’t ‘see’ such as rooftops and hard to reach spaces? The most common areas of laser scan data loss or ‘blackspots’, includes roof and ceiling areas, as well as other hard to reach areas. How to tackle blackspots in roof data: If there is no access onto the roof (e.g. it isn’t a flat roof) SUMO will use an extending pole. This allows us to survey up to 10.5 meters above the ground. Using the extending pole, we can suspend the laser scanning equipment above the roof areas and scan them from above, whilst maintaining accuracy. Alternatively, dependent upon site location, SUMO could consider using a drone and photogrammetry to fill in the missing data. Scanning Ceiling voids: For the most accurate representation of ceiling voids the answer is, of course, to take the suspended ceiling down for inspection and surveying. But, there are other options available to clients who don’t wish to go down this route. Using Hand Held Laser Scanning equipment to scan above the suspended ceilings can be a much faster and cheaper method of surveying ceiling voids. The limitation of this technique however is that the tolerance of the data is lowered. But in most cases, the Hand-Held scanning data is adequate for the purpose. If you need extremely detailed scans of the ceiling voids, then the traditional laser scanning and dismantling of the suspended ceiling would be the favourable option. Above: Hand-held laser scanning equipment being used to survey ceiling voids within an office space. Whatever your requirements, Laser Scanning has a wide range of applications to suit many survey areas. With the time and budget benefits, don’t waste yours! Contact SUMO today to discuss your requirements.

With the introduction of laser scanners to the mainstream survey industry, do we still need to follow the same old survey principles of working from the whole to the part? Laser scanners now enable us to scan anywhere at any time, with the ability to piece the data back together using advanced registration software. The jigsaw below represents the data collected from a site. Each jigsaw piece represents one scan. Each ‘piece’ may have been surveyed in a chronological order or they may even have been on different dates at different times of the day. In fact, adjoining pieces may even have been surveyed on different dates, due for example to access issues. All we need in each of the scans is an overlap in the ‘pieces’ of scan data and the registration software will be able to combine them to form the full ‘image’. The more hard-standing features there are within the survey area, the better the registration will be. Once the registration software has pieced together the data, we then have the complete image as shown above. This simple jigsaw example shows the flexibility that we have when using laser scanning. Back to the question, do we need to follow the same survey principles of working from the whole to the part? The answer is yes, of course, we need to keep the same survey principals! But with the knowledge that if we cannot survey areas A to F in chronological order and must instead survey them in a random order, there is, in fact, a solution by using laser scanning! Benefits: Having this large amount of flexibility when laser scanning, allows SUMO to scan larger buildings. This includes office blocks, hospitals and schools without losing precious time. For example when waiting for access to restricted areas of buildings, can incur higher costs for the client. Another benefit of laser scanning is that there is far less equipment needed on site. For example, if there are tight corridors or stairwells on site, we don’t need to have our ‘artificial geometry’ all over the site for people to kick or trip over. We also do not need to pick them up and move them from point to point, as the only item we need is the laser scanner and its tripod-mount. At the same time, because of using less equipment, we can have a much lower carbon footprint. We can travel light, by public transport or on foot, making laser scanning a win for the client and the environment!