imageSBL250x163This is an important time for 3D Information Modelling. With mandatory Government initiatives such as BIM and INSPIRE moving into key stages, the opportunities for 3D modelling services have grown significantly, with Wire Frame, Surface and Terrain models increasingly used as the primary means of transferring, storing and managing asset information throughout the entire project life-cycle.

"3D modelling from LiDAR or stereo aerial photography is now much more than a way of visualising and contextualising geographic information. It has become a genuine means of data and information management - as the growth of Building Information Modelling has proven. We are working closely with a number of UAV operators to facilitate their move towards provision of 3D products and services, and expect this engagement to increase, as the understanding of the benefits of 3D modelling grows," says Ian Dee of Ian Dee Consulting (IDC).

Geoff Blissitt, Sales & Marketing Director, SBL UK suggests - “The 3D spatial modelling initiative has two primary objectives: first, to remove data silos from within disciplines and organisations; second, to unlock the full value of the project information from closed, non-transferrable file formats and protocols, and make it accessible to all relevant stakeholders at any given stage in the project.” 

Fig. 1 - 3D Digital Surface Model (DSM) for Mining Project. Input data captured by an UAV.Fig. 1 - 3D Digital Surface Model (DSM) for Mining Project. Input data captured by an UAV.


The opportunity:
Surveying companies have been quick to respond; indeed they have been champing at the bit, waiting for government directives to drive the 3D agenda forward.

In the past there has been a degree of frustration: 3D models were primarily used as visualization tools for certain designated and delimited stages in the design process, whereas geospatial data experts have known for some time that geo-referenced 3D geometry offers an alternative means of extending the use of location-based project management functions across different project disciplines, both internally and externally.

This opportunity has already been embraced across a range of surveying techniques: from aerial photography captured by fixed wing planes, helicopters or UAVs through to airborne, mobile and ground-based LiDAR and point clouds.

In varying degrees, and with varying output specifications, geospatial surveying companies are modifying their skills, hardware and processes to maximise the benefits arising from 3D attributed models. SBL delivers data processing services to clients from all of these surveying groups, so we know that this opportunity is open to everyone, providing that the input data specifications are fit for purpose. End clients include major rail and highways operators, utilities, engineering consultants, mining companies, environmental consultants, and land and property developers.

Driving forces:
Fig. 2 - 3D Wire Frame. Input data captured as point cloud.Fig. 2 - 3D Wire Frame. Input data captured as point cloud.

Building Information Modelling (BIM): 
On 31st May 2011 the UK Government published its ambitious plans to reduce both capital cost and carbon burden from the construction and operation of the built environment by 20%.

At the heart of this report was the Government’s intention to require collaborative 3D BIM (with all project and asset information, documentation and data being electronic) on its projects by 2016. The most important word here is ‘require’, as all businesses, contractors, sub-contractors and partners bidding for major UK Government Construction projects must demonstrate BIM compliance in order to be successful.

It is important to first understand that BIM is not a single product, software or process. Neither is it designed as a single function at a given stage in a project.

BIM is an over-arching term to describe the way in which technologies, processes and collaborative behaviours must interact to unlock more efficient ways of working at ALL stages of the project life-cycle, including Facilities Management following the As-Built completion.

Therefore even businesses which own but don’t build the commercial premises – such as large retail groups - should be taking an interest in the benefits of BIM.
It is also worth mentioning an assertion which is commonplace among BIM specialists: that in some ways the ‘B’ of BIM is perhaps misleading as the initiative relates to more efficient management of all infrastructure not just buildings. For instance the UK Rail and Road sectors are already heavily engaged in implementing BIM best practice.

In brief BIM has the following intended outcomes:

  • Efficient and useful sharing of data across disciplines, software and platforms. An example might be the transferral of design drawings at the architectural stage – typically in a CAD environment – to the spatial design at the engineering stage – typically in a GIS environment. In the past the file formats and software used by these disciplines has not allowed the full value of the data to be passed on.
  • The removal of data and discipline silos within organisations. This is especially true of the different needs traditionally expressed by teams working in 2D and 3D.
  • The ability to create attributed (geo)databases, whereby all the asset information is stored within a 3D wire frame and ‘hung’ on the location of the asset.
  • To To ensure that databases are live, editable and accessible to multiple parties at any given time. The databases should be a living and evolving information asset rich in detail.
  • The data structure should allow other datasets to be added and combined so as to allow bespoke queries, often spatial in nature, but always based on intelligent search functions. A GIS environment is tailor-made for this.
  • More efficient working practices, based on better and more accessible information, leading to better decision-making at all stages in the project life-cycle. This in turn will lead to more efficient project delivery and fewer disputes. It will also deliver considerable savings to the ongoing asset maintenance as data will evolve and remain relevant. 

As a leading ISO Accredited Technology company, SBL is already engaged in supplying services in support of BIM. We have a large and experienced GIS team which delivers 3D wire frames derived from LiDAR and Aerial Photography survey data. Our software division supports these efforts through the delivery of web-based GIS applications.

Fig. 3 - 3D Rail features. Input data captured as mobile LiDAR.Fig. 3 - 3D Rail features. Input data captured as mobile LiDAR.

INSPIRE Directive

The INSPIRE directive came into force on 15 May 2007 and will be implemented in various stages, with full implementation required by 2019.

The INSPIRE directive aims to create a European Union (EU) spatial data infrastructure. This will enable the sharing of environmental spatial information among public sector organisations and better facilitate public access to spatial information across Europe.

A European Spatial Data Infrastructure will assist in policy-making across boundaries. Therefore the spatial information considered under the directive is extensive and includes a wide variety of topical and technical themes.

INSPIRE is based on a number of common principles:

  • Data should be collected only once and kept where it can be maintained most effectively.
  • It should be possible to combine seamless spatial information from different sources across Europe and share it with many users and applications.
  • It should be possible for information collected at one level/scale to be shared with all levels/scales; detailed for thorough investigations, general for strategic purposes.

Geographic information needed for good governance at all levels should be readily and transparently available.

Easy to find what geographic information is available, how it can be used to meet a particular need, and under which conditions it can be acquired and used.

INSPIRE is based on the infrastructures for spatial information established and operated by the 28 Member States of the European Union. The Directive addresses 34 spatial data themes needed for environmental applications, with key components specified through technical implementing rules.

Delivering the opportunity

Light detection and ranging (LiDAR):
LiDAR is a cost effective method for obtaining feature rich and highly accurate building and terrain information. LiDAR's vegetation penetration properties allow precise measurement of topography, vegetation height and cover, as well as complex canopy attributes.

Also, LiDAR images are faster to process and easier to model into a range of thematic 3D maps. One can, for example, use LiDAR data to calculate the height of every tree, power line, or building in a thematic map.

Features can be segregated into classification types and then combined to form a complete 3D model based on a number of differentiated layers of data. The 3D geometry can then be attributed with information about the feature, for example its size, location and composition.

Fig. 4 - Example of an attribute table.Fig. 4 - Example of an attribute table.

LiDAR data processing and modelling services are used for a range of applications:

  • 3D Surface Models and Wire Frames
  • Attributed data models for BIM
  • 2D Cross Sections and Sc0 tunnel clearance files for integration into 3D models environment.
  • Vegetation classification models and tree mapping
  • 3D City and street models
  • Hydrographical models
  • 3D Building models
  • Utilities and power line models
  • Digital Terrain Models (DTM), Digital Surface Models (DSM), Contour and Slope models
  • Flood plain models with 3D break lines.

 

Method

  • Detection and removal of noise and outlaying points
  • Generation of intensity images
  • Terrain extraction, bare earth modelling, and data filtering
  • Street 3D view extraction from mobile LiDAR clouds
  • Advanced detection and extraction of buildings and features
  • Generation of elevation profiles: Wire Frames, DSM, DTM, TIN, contour, or slope models

Fig. 5 - Data LayersFig. 5 - Data Layers


Aerial and Satellite Imagery
Two key processes underpin 3D model creation from imagery: Photogrammetry and Remote Sensing. Photogrammetry techniques are used to extract accurate information and measurements of physical objects from photographs and then incorporate these objects in maps, drawings, or 3D models. Pre- and post-processing Photogrammetry is an essential requirement if the photographs are to provide useful and feature rich geodatabase information. 

Remote Sensing is used for feature classification, image correction, image enhancement, image processing, and change detection services. The aerial photographs are interrogated and converted into GIS vector layers which can be attributed and converted to 3D Wire Frame models.

Image6 650Fig. 6 - 2D Cross Sections integrated into 3D Surface Model.

 

Method

  • Aerial Triangulation
  • Orthorectification
  • Planimetric / Feature extraction
  • DEM / DTM Creation
  • 3D Conversion and Attribution

UAVs
In mission critical areas like surveillance, mapping and 3D modelling, UAV platforms are nowadays a valuable source of data.

The cost effectiveness and ease of operation of UAV platforms make it a low-cost alternative to classical manned aerial photogrammetry.
When it comes to small areas and extremely precise 3D dataset and low budget, UAV survey capture is the technology to rely on.

This is a very cost effective solution for small area mining, environmental, and agriculture. Acquiring very high resolution data in centimetre levels is a specialty of this technology.

Very high accuracy terrain models, ortho photos, thematic models and image draped 3D models area possible through UAV images by using suitable software platforms.

Fig. 7 - Digital Surface Model. Input Aerial Photography ImageryFig. 7 - Digital Surface Model. Input Aerial Photography Imagery. The typical domains where UAVs and photogrammetrically derived 3D data or its derivate products are useful include:

  • Forestry and agriculture: Stakeholders can take reliable decisions to save money and time (e.g. precision farming), get quick and accurate damage assessment or identify potential problems in the field. Assessments of wood lands/parcels, fires surveillance, species identification and volume calculation can also be accurately performed.
  • Archaeology and cultural heritage: 3D documentation and mapping of cultural and archaeological sites and structures are easily achieved with a low-altitude image-based survey.
  • Environmental surveying: Quick and cheap regular flights allow land and water monitoring at multiple time periods. Post-disaster response and mapping, excavation volume computation and natural resources documentations are also feasible.
  • Traffic monitoring: surveillance, travel time estimation, trajectories, lane occupancies, accident reconstruction and incidence response are the most required information.
  • 3D reconstruction: UAVs are a valuable source of image data for general 3D reconstruction purposes of man-made structures.

----------------------------------------------------------------------------------

For more information:

SBL Geospatial Services 

Author Vivek. K.S is Senior Manager (Production) | Geomatics at SBL Vivek is a geospatial professional with more than twelve years experience in GIS, Remote Sensing and Photogrammetry. Over the years he has gained experience in project management through various roles as Team leader and Project Manager in different organizations. He has been managing Photogrammetry, UAV and Remote Sensing domains at SBL for the past five and a half years. In this time he has proven to be an outstanding strategic leader, handling flagship projects with simultaneous management of multiple projects, utilizing ISO and Six Sigma standards. SBL were one of the first companies in India to take up and adopt the skills required for the opportunities presented by LiDAR and UAV technologies. Vivek is a skilful communicator, competent in forging partnerships with internal and external client teams.