Between the Poles

Canadian Underground Forum: Today is Day 1

We are starting at 10 AM EDT. You can see the program for April 29 and register here.

Today's speaker lineup

One of the early innovators in applying LiDAR to mapping underground pipelines, Joseph Hlady, President at Lux Modus in Calgary, Alberta will explain n his keynote the benefits that his technology has brought to the oil and gas pipeline industry. 

A number of jurisdictions around the world are developing digital twins at the urban, regional and even national level. In a lunch keynote Alex Shalash of UEVO will discuss creating a city subsurface infrastructure map which unifies fragmented information and produces an intelligent digital twin.

Our chief guest speaker is Jim Anspach, Chair of the ASCE 38 standards group, who will bring us up to date on two imminent ASCE standards.

Rob Martindale, Program Manager - Utilities/Railroads at the Colorado Department of Transportation, will present an overview on how a mix of legislation and regulation has enabled Colorado to revolutionize the capture and sharing of accurate underground utility location data. Page Tucker, President & CEO at ProStar which implemented the mobile and cloud solution adopted by the Colorado DoT will speak about developing a digital twin of the underground.

One of the remarkably innovative technologies applied to mapping underground infrastructure was developed by 4M-Analytics. Harel Dan, Head of GIS and Remote Sensing, and Ophir Wainer, Director of North America Business Development, will explain how 4M-Analytics uses satellite and aerial imagery to map underground infrastructure.

Government has a crucial role to play in locating and mapping underground infrastructure. Capping the first day of CUF Prashant Shukle, who was responsible for mapping and earth observation in the Canadian government for many years, will moderate a panel discussion on the role of government in underground infrastructure with panelists from the State of Colorado DoT, the U.K. Government's Geospatial Commission, Public Services and Procurement Canada, and Infrastructure Ontario.

Canadian Underground Forum begins tomorrow

You can see the program for April 29 and 30 and register here.

Speaker lineup

One of the early innovators in applying LiDAR to mapping underground pipelines, Joseph Hlady, President at Lux Modus in Calgary, Alberta will explain n his keynote the benefits that his technology has brought to the oil and gas pipeline industry. Another early innovator is Otto Ballintijn, CEO of Reduct who has developed inertial or gyro technology for mapping underground pipe networks. In his keynote he will explain the evolution of the technology including the concept, operational method, and data output of gyro mapping technology. A number of jurisdictions around the world are developing digital twins at the urban, regional and even national level. Alex Shalash of UEVO will discuss creating a city subsurface infrastructure map which unifies fragmented information and produces an intelligent digital twin. Danny Petrecca of Locusview, an early leader in capturing and managing underground data in the gas industry, will review why as-builting still remains paper-based and discuss a digital construction solution that stitches together existing technologies to create the reliable digital twin that utilities need in the age of the smart grid.

Our chief guest speaker is Jim Anspach, Chair of the ASCE 38 standards group, who will bring us up to date on the imminent 38-21 utility as-built standard. Carsten Roensdorf and Neil Brammall will introduce the Open Geospatial Consortium's work in progress, the MUDDI standard for exchanging location data about underground infrastructure. Lawrence Arcand, who has led Subsurface Utility Engineering (SUE) investigations on a national level since 2003, will provide an overview of the Canadian standard CSA S250:20 Mapping of underground utility infrastructure.

Rob Martindale, Program Manager - Utilities/Railroads at the Colorado Department of Transportation, will present an overview on how a mix of legislation and regulation has enabled Colorado to revolutionize the capture and sharing of accurate underground utility location data. Page Tucker, President & CEO at ProStar which implemented the mobile and cloud solution adopted by the Colorado DoT will speak about how the partnership between Colorado DoT and Prostar made this successful. One of the remarkable new technologies applied to mapping underground infrastructure was developed by 4M-Analytics. Harel Dan, Head of GIS and Remote Sensing, and Ophir Wainer, Director of North America Business Development, will explain how 4M-Analytics uses satellite and aerial imagery to map underground infrastructure. Leica Geosystems' IDS Georadar was one of the early innovators in ground penetrating radar. Simon Pedley, Detection Ambassador at Leica Geosystems will talk about some of the innovations in hardware and software that Leica Geosystems has developed in the last couple of years.

Government has a crucial role to play in locating and mapping underground infrastructure. Gord Reynolds and Alon Gat will discuss how Infrastructure Ontario partnered with Metrolinx and the Ministry of Transportation to establish the Utility Coordination Program (UCP), a new initiative which oversees the development of utility relocation standards and the supporting process to improve the location, treatment and relocation of utility infrastructure. Gordon McElravy, of buildingSMART Canada, will discuss buildingSMART's efforts in implementing the Municipal Infrastructure Council Program to encourage building information model (BIM) initiatives at the municipal level. Capping the first day of CUF Prashant Shukle, who was responsible for mapping and earth observation in the Canadian government for many years, will moderate a panel discussion on the role of government in underground infrastructure with panelists from the State of Colorado, the U.K. Government's Geospatial Commission, Public Services and Procurement Canada, and Infrastructure Ontario.

Standards for underground location quality are rapidly evolving

In the last two years quality standards for location quality of underground infrastructure in the U.S., Canada, U.K. and Australia have been revised or augmented.  This reflects the accelerating development of new technologies and evolution of existing technologies.

For example, the release of the new ASCE Standard Guideline for Recording and Exchanging Utility Infrastructure Data (also referred to as the utility as-built standard) developed under the auspices of the American Society of Civil Engineers (ASCE’s) Construction Institute(CI) and Utility Engineering and Surveying Institute (UESI) is imminent. Its purpose is to facilitate data collection, data management, and data exchange among stakeholders. It is designed to complement the widely used ASCE 38-02 Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data.  As a reminder ASCE 38-02, published in 2002, is intended to standardize the classification of the quality of location information about existing subsurface utility networks on engineering drawings. The standard defines four quality levels based on the method used to determine the location of underground assets.

It is interesting to review global underground location quality standards and see that most of these standards have evolved in the last years which reflects the accelerating development of new technologies for detecting and locating underground infrastructure.  For example, ASCE 38-02 is not prescriptive with respect to accuracy and is generally 2D in focus.  Recent quality standards such as the soon to be released ASCE as-built standard, PAS 128, the French DICT, and Canadian CSA S-250 specify accuracy levels in 3D.

1986 – Japan, Road Administration Information Center (ROADIC)

1998 – Japan, Road Management System (ROADIS) provides de facto standard

2002 – U.S. ASCE 38-02

2006 – Malaysia Standard Guideline for Underground Utility Mapping

2011 – Canada CSA S250:11

2012 – France Presidential Decree relating to excavations near underground, overhead or underwater transmission or distribution networks

2013 – Australia AS 5488

2014 – U.K. PAS 128

2015 - Ecuador NTE INEN 2873

2017 – U.K. PAS 256

2019 – Australia Revised AS 5488.1:2019

2020 – Canada Revised CSA S250:20

2021 – U.K. Revised PAS 128

2021 – U.S. ASCE Standard Guideline for Recording and Exchanging Utility Infrastructure Data aka “Utility as-built standard”

Advances in capturing and sharing location information about underground infrastructure in Europe

I was invited to participate in a meeting of the European Underground Infrastructure Community this morning.  I heard about very important advances in capturing, capturing and sharing location information (maps) about underground infrastructure that are relevant to any jurisdiction attempting to reduce underground damage and improve construction efficiency.

France

In 2012 a presidential decree mandated that the location of underground infrastructure had to be accurate to 40 cm or better (Quality Level A) for all critical infrastructure in urban areas by 2019.  In France critical infrastructure refers to infrastructure that is dangerous for excavators.  It excludes telecom and most water distribution networks. At this point the target date has slipped a bit, but it is estimated that about 80% of the location of urban underground infrastructure is known to QL A.

It is important to note that this applies not only to new infrastructure but existing infrastructure as well.  One of the contributors to the improvement in the quality of existing infrastructure data is a shared responsibility model.  As a contractor I am expected to request information through the DICT system about the location of underground infrastructure in the areas of a proposed excavation.  If the information supplied by the network owners operating in that area is poorer than QL A, I can invoice the network operator for the work I have to do to achieve QL A.  This system motivates network owners to work toward improving the quality of their data to reduce the cost of paying invoices. Furthermore, the cost for a contractor to do this work is probably significantly higher than if the network operator undertakes the work themselves.

Netherlands and Flanders

Studies from the 1940s through today have shown that incorrect or incomplete knowledge about the location of underground utilities is the leading reason for project delay claims.  A study of ten  Pennsylvania Department of Transportation (PennDoT) projects that involved a subsurface utility engineering (SUE) survey prior to engineering design found significant business benefits with an ROI of $22.21 saved for every dollar invested in SUE. Most one call centers are designed to provide underground utility information just prior (in North America about three days in advance, in the Netherlands up to 20 days in advance) to shovels going in the ground.  What this means is that planning and engineering design are conducted blind about the location underground utilities. The result is increased risk of utility damage, unnecessary but expensive utility relocations and construction delays.  In the Netherlands the KLIC system now can respond to three types of information requests, safe digging requests (80% of all requests), emergencies (5%), and planning requests (15%).  In Flanders similarly about 16-17 % of information request to the KLIP system are study requests.  This means that areas of high risk from underground infrastructure or where areas where utilities relocates would be expensive can be avoided during the design process.  Nobody would begin engineering design for a civil engineering project without a (above-ground) survey by a registered professional land surveyor.  Having accurate, reliable information about underground utilities is just as important.  In addition to the Netherlands and Flanders other jurisdictions are recognizing this as well.  In Colorado a SUE survey prior to civil engineering work in the public right of way is now mandatory.

In both Flanders and the Netherlands data is shared using an open standard harmonized data model (IMKL) that allows all data for a proposed excavation to be downloaded as a ZIP file and visualized on a single layered map using a free and open basic, commercial, and in-house developed viewers, supporting both offline and online viewing,

Germany

Red - inquiries handled conventionally. Green - inquiries handled by BIL system

In Germany there has been rapid growth in the number of request for information about the location of underground pipelines.  BIL is the Germany-wide information system for pipeline inquiries. Since February 2016 BIL has provided a cost-free digging request portal to a the national information system for pipeline inquiries. The foundation for BIL was laid in 2015 by 17 German pipeline companies from the chemical, high-pressure gas and mineral oil sectors. To date the BIL system has been able to automate 80% of these requests, with the result that  turnaround times are faster and require less staff.

It is interesting that 30.36 % of requests to the BIL system were for planning purposes (pre-construction) and the remainder for excavations.  This varies considerably for different sectors from about 20 % for civil for different sectors. While civil engineering and pipeline construction predominantly inquired about excavation, significantly more planning inquiries were made in the area of ​​energy generation and special measures (railway infrastructure, hydraulic structures, tunnels, industrial areas)

Spain

Two regions in Spain, Catalonia and Navarre, have developed non-governmental industry consortia for sharing information about the location of underground infrastructure,  These consortia are industry-supported, primarily by large utility and telecom operators such as Telefonica, ENEL, and Iberdrola.  Excavators pay a fee to retrieve this information which is provided as vector data, in AutoCAD, Microstation or shape file formats.

Thanks to Holger Kessler for the opportunity to participate.

New standard for capturing information about underground utilities exposed during construction

In Germany a new standard for documenting and exchanging information about underground infrastructure exposed during construction has been developed. Referred to as DIN SPEC 91419 it provides a standardized way to capture and share a wide range of information about the underground and has important implications for the continuous improvement in the reliability of location and other information about underground infrastructure.

Despite the documentation (records) about their networks maintained by utility and telecom network owners, what is actually underground and where it is located remains uncertain. A wide range of technical issues can only be identified after exposing underground infrastructure.  Information about the underground that is inaccurate, out of date and often missing means that engineering designs often have to be modified on site after construction has begun. This results in inconsistencies between design and what is actually built which are largely undocumented. "As-designeds" are submitted as "as-builts" and the viscous cycle continues.

Providing a mechanism for improving the quality of network documentation and records is being recognized as an essential component of a program for reducing damage to underground utilities. For example, The Colorado Department of Transportation (CDOT) has implemented a cloud and mobile system that incorporates elements of survey and GIS practice and technology. The system provides for recording and sharing the location and other information for underground utilities from SUE surveys, surveyors and other sources among CDOT, large and small construction contractors, network operators, and other stakeholders. Access to this data is provided over the web, enabling staff to access underground utility location maps on a handheld in the field at a construction site. The CDOT system includes an important capability that enables input from handhelds in the field during construction. This increases field staff engagement and enables staff to actively contribute to improving the accuracy of location and other information stored in records.

The prototype system developed for the National Underground Asset Registry pilots in the U.K. for sharing location and other information about underground assets among government roads agencies, network operators and others includes a similar field feedback mechanism.   Referred to as “observations”, comments on discrepancies between what is shown by the system and what is actually observed in the field as well as changes made during construction can be reported and are incorporated with their location in the NUAR database. I believe that the latest version of the KLIC system in the Netherlands also implements a similar capability.

The new standard for the documentation and exchange of data about underground infrastructure exposed during construction uses XML encoding.  It provides a standardized way to capture and share a wide range of information about the underground including

• Name, role and affiliation of data provider. Roles include surveyor, construction foreman, site manager, excavator, project leader, structural engineer, etc.
• Location of site where data is reported
  
• Content can include technical reports, observations, notes, photos and videos
  
• Keywords characterizing the information such as subsoil investigation, BIM model, gas pipeline, cable duct, storm sewer, sanitary sewer, etc.

Example of photo and other information about utilities exposed during excavation

An online system localexpert24 has been developed that allows sharing of information about the underground.  This system provides all stakeholders on a project access through a very simple interface to all the information about the underground that a local expert considers to be important - in essence providing a situation assessment for the underground.

To put this in a broader context procedures and technologies for raising the level of accuracy, timeliness and completeness of the location and other information about existing underground infrastructure is one of the most important measures for reducing damage to underground utilities during construction. Enabling direct input from the field, where staff can see what is actually in the ground, and sharing this information are indispensable to a program of continuing quality improvement in information about the underground.

Many thanks to Markus Becker, founder of localexpert24.de and one of the initiators and authors of the DIN SPEC 91419 standard, who brought this remarkable initiative to my attention.

Above and underground infrastructure comprise Rotterdam's open digital twin

The City of Rotterdam is developing a digital twin of the city.  3D vector and image data of the above- and underground infrastructure, zoning regulations and city by-laws, data streams from real-time sensors, applications and simulations will comprise Rotterdam's digital twin. It is envisaged that the digital twin will enable the city to assess the impact of proposed changes in bylaws and regulations by simulating them before they are implemented. Rotterdam, and in fact the whole of the Netherlands have adopted transparency and open data as a pillar of government and are basing 3D models on open national and international standards, intend for the 3D data to be open and accessible to the public, and intend to use open source software wherever possible.

Many cities have 3D models of their aboveground infrastructure; buildings, transportation networks, parks, and other infrastructure typically captured in 2D or 3D imagery from overflights or in 2D GIS maps.  Imagery is not very smart and extracting 3D vector objects such as building footprints, heights, profiles and transportation networks requires sophisticated post-processing.  Even more importantly, underground infrastructure is usually neglected, even though it is recognized that water and wastewater, energy (gas, electric power, and district heating),  and communications (fibre and copper) networks provide the life blood of the city.

Rotterdam has been developing its 3D model, which underpins the digital twin, for several years.  Currently it contains street furniture such as street lights, trees and underground parts of street furniture, a large scale basemap, a complete map of underground networks of cables and pipes, buildings, and non-physical content such as zoning regulations and  bylaws.  The 3D model is kept in sync with data repositories maintained by city departments and others.  In the future it will also include real-time data streams from a variety of sensors. 

The 3D model is open, based on open standards and many of the applications that have been developed for it are open source projects. For example, visualizations rely on Cesium, an open source initiative which has just announced support for visualizing underground utilities, mines, and geological layers. The rationale for the data being based on open standards is that an standards-based environment creates an open data commons where developers can devote their time to developing innovative applications rather than spending time converting data from one format to another.

The Dutch 3D standard is an integration of CityGML Application Domain Extension (ADE) and the existing national IMGeo standard for large-scale representations of roads, water bodies, and land use. The Dutch Kadaster, Geonovum, the Netherlands Geodetic Commission and the Dutch Ministry of Infrastructure and Environment initiated a "3D Pilot NL" to develop a national 3D standard.  Existing intnernational standards including CityGML(Open Geospatial Consortium), IFC (buildingSMART), and others were investigated. The findings of the pilot  resulted in a national 3D standard implemented as a CityGML Application Domain Extension (ADE) that integrates the latest version of the existing Dutch national standard IMGeo 2.0. 

Current applications (virtualcitySYSTEMS, ESRI, IMAGEM and Unity) use the 3D model as input for analytics and visualization. One can imagine many use cases for the data in the Rotterdam 3D model. Among these three use cases have been identified as low-hanging fruit; climate adaptation, viewsheds and energy performance of buildings. 

Much of Rotterdam is below sea level and managing rain water accumulation during heavy rainfalls is a major issue. which affects building basements, subway entrances, low-lying roads, electrical transformers, and other infrastructure.  To address this problem, the concept of "water squares" has been developed and the 3D model used to determine the optimum location for these..  Water squares are open areas where water can safely be allowed to accumulate during heavy rainfalls to avoid overstressing storm sewers. 

In another application of the 3D model data, building data can be filtered and streamed to energy performance applications that provide insights into how buildings perform.

Open standards and open data also enables the sharing of data among cities in the Netherlands.  The Dutch Kadaster has developed an open 3D map of the whole of the Netherlands, with scales ranging from 1:500 to 1:25,000 in collaboration with academic, private sector, and public sector partners.  All data in the 3D map is built on the basis of open standards.  The map was created by combining existing 2D data with the Elevation Model of the Netherlands resulting from a LiDAR survey which covers the whole of the Netherlands with a resolution of eight elevation points per square meter.

Open data and open standards also relate to a critical issue that is of growing importance. Many governments have adopted transparency and open data as a cornerstone of democratic policy.  But often digital twins for smart cities are being developed by private-sector firms or by public-private initiatives.  As William Davies points out in Nervous States, "the IT infrastructure used to build e-geovernment projects or "smart cities" comes from the commercial sector, and the companies that provide it often retain control over the data that results." 

For example, recently a joint Alphabet/Google/Sidewalk Labs and City of Toronto initiative to develop a smart city on Toronto's waterfront foundered and was cancelled.  One of the reasons, it is argued, is that a technology giant such as Google (or Facebook, Amazon, ...) is not a vendor in the traditional sense, but a "surveillance capitalist" that collects and analyzes behavioural data captured from users for its own economic imperatives.  In the context of a smart city the opportunities for data collection from citizens and from systems such as water and wastewater, transit, waste removal, traffic management, and others are immense.  If this data is appropriated and becomes proprietary, it puts a private entity in a position to supplant democratic government, which doesn't have access to this huge volume of data and the analytics which extracts information from it.  Relying on open standards and ensuring that data is open and accessible to the public are essential to avoid citizens' and municipal data becoming proprietary.  Furthermore, using open source software and, I would add, open training data for machine learning applications helps avoid the problem of the analytics also becoming proprietary.

Based on a Webinar by Christian Veldhuis, Advisor City of Rotterdam, Rick Klooster, CCO, FUTURE INSIGHT and Antje Kunze, Director Sales & Marketing, virtualcitySYSTEMS.

Survey delineates subsurface utility engineering (SUE) adoption in Canada

The Centre for Advancement of Trenchless Technologies(CATT) has just released the report of a survey designed to better understand the current state of subsurface utility engineering (SUE) practices, barriers, and acceptance across Canada.  The most important conclusion of the survey is that most organizations rely on as-built records (which are frequently inaccurate) and surface site inspections (which can only infer the location of most underground utilities) for underground utility location information.  Furthermore, this information is used primarily during the construction phase of a project, not during planning and design, when accurate underground utility information has its greatest value. It was found that many organizations still do not update or request reliable as-builts during construction projects. The survey found that for most organizations SUE is conducted on a project-by-project basis, instead of being a standard process as part of construction projects. 

The target audience for the survey included infrastructure owners, consultants, contractors and technology providers – the main stakeholders in the SUE industry.  84 % of respondents were from Ontario with the remainder from other provinces.  46 % of respondents were infrastructure owners, and 43% engineering consultants.  70% of the infrastructure owner respondents represents large municipalities. More than half of the respondents had five or more years of experience with SUE on construction projects.  The remainder reported one year or less of experience with SUE.

Analysis

The survey revealed that Quality Level D (as-builts and other records) and Quality Level C (surface site inspections) comprise the most frequently used information about the location of underground utilities.  Only 15 % of respondents regularly used more reliable Quality Level B (remote detection) data during the planning phase of construction projects and less than a third used remote sensed data during the design phase.  For those using remote sensing technologies, 79% reported using electromagnetic methods, 16 % ground penetrating radar, and 15 % magnetic methods.

Two thirds of infrastructure owner respondents reported that their organization requires combining as-builts into their records or GIS system and about the same proportion reported updating their records database during construction.  But 59% said that they do not periodically review, verify and update utility records.  Very few of these, only 4%, said they are planning to implement a SUE program.

Almost all of the respondents (87%) were aware of SUE and many (70 %) had some SUE experience.  59% of the respondents were aware that SUE reports and drawings need to be stamped by a professional engineer (P.Eng.) or Professional Geoscientist ( P.Geo.).

Respondents were asked about their familiarity with standards relating to underground utility information including CSA S250 Mapping of Underground Utility Infrastructure, TAC Guidelines for the Coordination of Utility Relocations, ASCE 38-02 Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data, CSA Z247-15 Damage Prevention, or ISO 15489-1:2001 Information and documentation — Records management.  Less than half of survey respondents reported awareness of some of these standards.  The best known standards were CSA S250, ASCE 38-02 and TAC Guidelines.  Very few respondents were aware of ISO 15489-1:2001.

Australian water utility provides open access to water and wastewater network location data

Open data has become a goal for many governments, but is relatively rare among utility and telecom network operators and owners.  In Australia several water and wastewater network operators have made the location of their underground networks open and publicly available.  I had a chance to chat with Charles Moscato, Spatial Information Officer at Yarra Valley Water (YVW) about  their implementation of an open data portal which allows planners, designers, contractors and others to access and download raw geospatial data showing the location of YVW's underground facilities.

Background

Open data has been gathering momentum among governments.  An important impetus was the United States Federal Government where data has been in the public domain since 1909. The principle of free and open access to government geospatial data has been adopted by many governments including US Federal, Canada, Japan, South Africa, Brazil, California state and counties, and by municipal governments.  In 2013 G8 leaders (Canada, France, Germany, Italy, Japan, Russia, United Kingdom, United States, and the European Union) signed a charter on open data.  The Ordnance Survey in the UK began releasing some of its data with open licensing as part of its OpenData initiative in 2010, but it wasn't until 2018 that the OS Mastermap was made openly available for the public and businesses to use.There is even an open data site showing underground natural gas flow and gathering lines in Colorado.

But being able to access prepared maps and other derived material is just a first step, governments need to provide access to raw geospatial data in commonly used Web-friendly formats. In the U.S. Data.gov was launched in late 2009.  In 2013, President Obama issued an Executive Order making open and machine readable the new default for federal government information in the United States.  At the municipal level North Shore City, NZ and Vancouver, Canada have been in the forefront of municipal open data.  By 2008 North Shore City had made its water, waste water and storm water network infrastructure publicly available on the web.  Vancouver's open data portal was initiated in September 2009.

A major motivation for open data has been government transparency.  But there is also evidence that open geospatial data contributes to the economy.  In 2008  Australia and later New Zealand commissioned studies of the contribution of spatial data to the national economy that have concluded that with appropriate government policies (such as open geospatial data) the contribution to the GDP, estimated to be on the order of 1%, could be doubled.

Open access to utility network location data

In Australia 12 local governments and water utilities have made the location of their water network open to the public.  The City of Gold Coast was the first in 2014. 

Yarra Valley Water serves over 30% of Victoria's population with water and wastewater services including 764,000 residential and 57,000 business customers. Historically the groups who needed access to the location information about Yarra Valley Water's underground network were (1) planners, surveyors, designers and other utilities who needed to plan around, build near or to connect to water and wastewater assets and (2) excavators and construction contractors who needed to avoid damaging underground utilities during excavation.

The process used by Yarra Valley Water to extract and provide this data was arduous, time consuming and slow.  20-30 request were processed per week requiring one full time person.  The turnaround time was typically about 10 days.

Business case for open data

In addition to a broad initiative at all levels of government to improve government transparency by making government data open, specific business benefits were identified.  The first objective was to make the process of providing accurate location and other data to designers and contractors more efficient freeing up one FTE for more valuable tasks.  Secondly automating the process would improve internal workflows for capturing, updating and publishing data.  Thirdly, replacing slow paper-based processes for data visualization in the field.  Another benefit, whose importance for improving data quality cannot be overestimated, is the ability for users of the data to report discrepancies. Another benefit is the avoidance of potential litigation when data was found to be incorrect.  From a business risk perspective an on-line system simply made access more efficient to data that was already publicly available via the Dial-before-you-dig (DBYD) service.

Data quality

In the mid 80’s to early 90’s the location of underground water and wastewater assets was digitized from paper drawings at various scales.  In Metropolitan Melbourne wastewater assets at 1 : 500 and water at 1 : 1000. In rural Melbourne both wastewater and water were captured at 1:25,000.  Attribute information was manually keyed in which was an error prone process.  The challenge was to find a way to convey to users the reliability of the data.

In 2018 Yarra Valley Water implemented the Australian quality standard AS 5488 - 2013 which provides users with a measure of the quality of location data enabling them to assess risk.  The AS 5488 quality levels are quite different from the U.S. ASCE 38-02 quality standard and the U.K. PAS 128 standard. The AS 5488 -2013 Quality Levels specify an absolute or relative accuracy.

1. Absolute subsurface feature location ±50 mm horizontally and vertically

2. Relative subsurface feature location ±300 mm horizontally and ±500 mm vertically

3. Relative spatial interpretation of position ±300 mm horizontally with indicative depths

4. Unverified and approximate position, roughly ±1 to 10 metres horizontally

About 75 % of Yarra Valley Water asset data was assessed a “D” Data Quality Level, this is either older data (2000s and earlier) or data with no association to a field survey.  After the 2000s the quality of asset location data is assessed at Quality Level C.  Typically this involves a site inspection to determine the location of visible above ground features and inferring the location of connecting pipes.

Open online access to network location information

In 2016 Yarra Valley Water decided to implement an on-line web application that contains up-to-date locations of current and proposed sewer, water and non-drinking water infrastructure in one easy-to-use map.  The site is updated daily with the latest available information and is open to all Australians.  The site was inexpensive to implement because the technology to do this has been around for a long time and was already used internally within Yarra Valley Water. The site provides a web map allowing users to browse the data.  Implementing this site freed up one FTE that had been dedicated to responding to requests for information.

But the most important feature is that once a user finds an area of interest, they can download raw geospatial vector data using the Open Geospatial Consortium (OGC) Web Feature Service (WFS) standard.  This capability allows users to extract data when they need it, whether for planning, design or construction. This capability has appealed to designers, in particular, because it allows them to integrate the data into their CAD or BIM design tool. The significant benefits that result from knowing the location of underground utilities prior to design are well known.

Currently field staff and customers can report errors, but this process is currently arduous and the capability is used infrequently.  There is an initiative underway to replace this with a very simple way to report data errors such as incorrect location, wrong material, or inaccurate pipe diameter.  In the future it may be possible for vetted customers to make corrections to the data directly.

This is an example of the direct business benefits of open data for network operators and to the wider construction community.  It illustrates that implementing an open web portal is inexpensive and can have immediate tangible business benefits.  But perhaps more importantly it provides significant benefits for a number of use cases including utility damage during construction, emergency response, and an essential part of smart cities.

Initiative to develop open standards for AEC and geospatial interoperability

The effects of population growth, urbanization and climate change are motivating us to contemplate serious changes in how we build and maintain buildings and infrastructure. This change will require new tools. There are important industry drivers that suggest that AEC (architecture, engineering and construction) and geospatial interoperability is one of them. A specific challenge currently facing the AEC and geospatial industries is integrating building information models (BIM) and geospatial infrastructure models for full life-cycle project workflows. Autodesk and ESRI have announced a partnership to further the integration of AEC and geospatial models and data which is already showing tangible results, but in a proprietary environment. A recent paper by the Integrated Digital Built Environment (IDBE) joint working group working group, a collaborative effort by buildingSMART International (bSI) and the Open Geospatial Consortium (OGC) to further open standards for AEC/geospatial interoperability, has identified the conceptual and other incompatibilities between the geospatial and AEC modeling of built infrastructure and suggested a way forward toward addressing incompatibilities.

Clashing tectonic plates

The BIM+geospatial problem is the latest symptom of a broader problem. I began working in the utility and telecom sector in 1993, specifically in developing software for records management (called network documentation outside of North America), and at that time the magnitude of the AEC+geospatial cultural mismatch problem was just beginning to be appreciated by utilities and telecoms. The Between The Poles blog is nearly 15 years old and one of the persistent themes from the very beginning in 2006 was the challenge of integrating CAD and GIS data in a common workflow (some examples; 2006, 2007, 2008 ). In utilities and telecoms planners tend to use GIS tools, engineers and designers CAD tools, construction folks in the field paper CAD drawings, and asset managers GIS integrated with their FM tools. Fashioning AEC and geospatial data into an efficient data flow from planning through design and construction to operations and maintenance continues to be a challenge.

There are parallels between what happened in the 1990s in unsuccessfully addressing CAD+GIS interoperability and the current challenge of BIM+geospatial interoperability. But there are also important differences which provide grounds for optimism that the availability of open standards for both BIM and geospatial, a vibrant open source geospatial community, and a new willingness on the part of major software players in the BIM and geospatial industries will make it possible to successfully address the latest interoperability challenge facing the AEC (architecture, engineering and construction) and geospatial industries.

Building information modeling (BIM) has been applied to design-build construction projects for many years. A growing number of countries are mandating BIM for public projects. While the UK government has said that "...we know that the largest prize for BIM lies in the operational stages of the project life-cycle", until recently there has not been hard data to support this conjecture. Similarly there has been only anecdotal support for an integrated BIM and geospatial approach for design, build, operate and maintain projects. Now we are beginning to see data from real world projects that offer evidence for the benefits of an integrated BIM+geospatial full lifecycle approach for construction projects.

Research in the Netherlands at the Delft University of Technology delved into interoperable digital building and infrastructure model standards developed to serve the AEC (architecture, engineering and construction) and geospatial sectors. Specifically, the research was focused on translating the geometry and topology of 3D digital BIM models represented in buildingSMART's Industry Foundation Classes (IFC) standard into 3D forms compatible with the Open Geospatial Consortium's CityGML standard. The researchers found is that there is more than one way to transform a BIM model to CityGML. While it was possible to transform most BIM models, it is not possible to convert all BIM models to CityGML.  The findings of this research has reemphasized the challenge of integrating AEC and geospatial data, the first major industrial symptom of which appeared over 25 years ago in the form of 2D integration of CAD and GIS.

Comparison of IFC, CityGML, and LandInfra

The IDBE working group is a joint collaboration between buildingSMART and the OGC.  Among the first products of IDBE is a paper Built environment data standards and their integration: an analysis of IFC, CityGML and LandInfra that described the incompatibilities and similarities among three open standards used in the AEC and geospatial worlds.

The three standards are IFC (Industry Foundation Classes), developed by bSI, is used predominantly for exchange of rich, fine-scale building and infrastructure data in the AEC industry, CityGML, an OGC standard, for capturing large scale urban data including buildings and transportation infrastructure originally for simulations, and LandInfra, jointly developed by bSI and OGC, for modelling land and civil engineering infrastructure facilities and designed as a successor to LandXML.

An important difference among the standards is how real-world objects are conceptualized.  IFC represents a building as an aggregation of building elements such as walls, doors, and windows, CityGML represents internal building volumes as rooms, and LandInfra represents buildings as features of a facility with only an outer shape and footprint.

Another important difference is coordinate systems. IFC uses a rectilinear coordinate system to represent structures in engineering precision over relatively small, flat surfaces.  CityGML and LandInfra model structures that need to take into account the Earth's curvature and therefore use an appropriate geographic projection system.

The standards use different geometric representations of objects.  CAD and BIM design tools use splines, nurbs, spirals and many other parametrized forms.  Geospatial applications generally use points and multi-point lines and polygons.

Topological relationships are also handled differently. In CityGML, topologies such as containment or spatial adjacency are represented implicitly in the boundaries between different geometric objects.  IFC defines objects and their geometries and separately and explicitly identifies topological relationships between them.

Level of Detail and Level of Development (LOD) are handled differently.  CityGML uses LOD to progressively define more detailed representations of a structure. For example, for a house; LOD 0 is a building footprint; LOD1, a 3D volume; LOD 2 includes a 3D roof geometry, LOD 3, windows and doors, and LOD 4 detailed structures and furniture. Levels of Development in BIM refer to levels of progress through a construction project and does not correspond to LODs in CityGML. There is no concept of LOD in LandInfra.

Conclusion

The consequence of these differences among the standards is that software interoperability and data integration are difficult.  Three approaches to resolving this interoperability challenge have been proposed.

• Schema mapping: This approach attempts to map each object in one standard to be mapped onto its nearest match in another standard.  The TU Delft research described earlier investigated this approach and concluded that unambiguous mappings between CityGM and IFC was not possible in all cases.
  
• Federation: Another approach is to support multiple schemas in one representation.  For example, a Revit BIM model can be displayed in a geospatial environment.This limits the generality of some operations such as spatial search, spatial analytics, and CAD and BIM operations.
  
• Link referencing: A third approach is a linked federation using embedding links in the primary model to components from instances of secondary schemas. The feasibility of such an approach was confirmed in OGC Testbed 4 (2007), in which web services were used for 'merging' CAD, GIS and BIM data.

Next steps

The IDBE has made several recommendations for moving forward to resolve the latest AEC/geospatial interoperability challenge in an open, standards-based way.

• Identify and prioritize uses cases.
• Compile a shared vocabulary and a shared resource for identifying synonyms across different domains.  An example of the latter is the CB-NL developed in the Netherland for mapping synonyms across the construction life-cycle.
• Develop a best practice document for coordinate systems for 3D georeferencing.
• Devise a system of common unique identifiers (Oids) for real-world, physical objects that remain
  constant and unique.
• Collaborative approach for harmonizing conceptual models.
  

I would add that owners of buildings and infrastructure, recognizing that an important benefit of open interoperability standards is increased competition among software vendors, should consider ways that open standards are incorporated into their procurement requirements.  Government procurement was a major driver that motivated virtually all BIM tool vendors to incorporate IFC support into their products.

Revision to PAS 128 standard for locating underground utilities available for public comment

A revision to the PAS 128 2014 standard for locating underground utilities is available for public comment through March 16.

PAS 128 defines a hierarchy of detection methods for detecting underground utilities in terms and the maximum quality levels that can be achieved using each detection method. In a PAS 128 survey, at a minimum two techniques (EML and GPR) are deployed. In addition to EML and GPR, other detection methods may be applied to the survey area. PAS 128 sets out the accuracy to which the data are captured, the quality expected of these data and a means by which to assess and indicate the confidence that can be placed in the data.  To improve accuracy and how data are exchanged and integrated, PAS 128 encourages capturing the absolute geospatial location of utilities georeferenced to 3D using a national coordinate grid system and datum such as the Ordnance Survey’s National Grid (OSGB36) and Ordnance Datum Newlyn (ODN) coordinates and the Irish Grid (IG) as used by Ordnance Survey Northern Ireland.

The quality level is a classification applied to each segment of utility surveyed based on survey method (D,C,B or A), location accuracy achieved (A, B1, B2, B3), and whether post-processing was performed (e.g. B2P).

A number of issues identified in the 2014 version of the standard are now being addressed in a revision. An academic study from the University of Birmingham investigated the effectiveness of the British PAS128 2014 standard for underground utilities. Test pits revealed that achieving a high vertical accuracy with remote detection techniques was problematic.  Furthermore, it was found that while using multiple technologies for detecting underground infrastructure significantly increased the confidence in the detected location of underground utilities it did not increase the accuracy. Other issues that have been identified and taken into account in the latest revision include; the current standard is addressed to practitioners but neglects owners/clients; the current standard assumed a 2D world, 3D and BIM need to be taken into account; whether to include post-processing of GPR scans needs to be revisited; and finally there were inconsistencies between PAS256 and PAS128.

As a reminder PAS 128 Bx quality levels were defined as

Quality level	Location accuracy Horizontal	Location accuracy Vertical	Comments
B4	Undefined	Undefined	Undetected
B3	+/- 500mm	Not determined	One geophysical technique
B2	+/- 250mm	+/- 40% of detected depth	One geophysical technique
B1	+/- 150mm	+/- 15% of detected depth	Two geophysical techniques

 

In revised standard quality levels D, C, and A do not differ materially from the 2014 version, but now all Bx levels require the application of at least two detection techniques.

 

Survey type	Quality level	Location accuracy Horizontal	Location accuracy Vertical	Comments
Desktop utility records search	D	Undefined	Undefined	As recorded in as-built record
Site reconnaissance	C	Undefined	Undefined	A segment of utility whose location is demonstrated by visual reference to street furniture, topographical features or evidence of previous street works
Detection	B4	Undefined	Undefined	a segment of a utility is shown as either a QL-D or QL-C on as-builts but was not detected using either GPR or EML
Detection	B3	± 500mm	Undefined	utility is only detected horizontally with one technique
Detection	B2	± 250mm	± 40% of detected depth	one or both techniques (EML and GPR) have detected the utility but  in different locations within the tolerance stated, or the utility was detected with just EML
Detection	B1	± 150mm	± 15% of detected depth	the utility has been detected using both GPR and EML in different locations within the tolerance stated.
Verification	A	±50 mm	±25 mm	Horizontal and vertical location of the top and/or bottom of the utility.

 

The 2014 version included guidelines targeted on the locate practitioner on how to use the standard.  In the revised version there are now Annexes B and C aimed specifically at the client/owner explaining how they should use this document.

By the way the new ASCE Standard Guideline for Recording and Exchanging Utility Infrastructure Data (also referred to as the utility as-built standard) will be available for public comment shortly.