Lidar and Sound Modelling

Improving Existing Propagation Models

Simulation of sound propagation is key for today’s urbanised society, in which sound is omnipresent and often negatively affects people’s lives. Existing methods of sound-propagation modelling fail to capture the complexity of terrain. Airborne Lidar in conjunction with aerial photos is able to fill this gap. The authors propose a programme of research to find out how high-resolution terrain data might improve the efficiency of sound models. Sound propagation is affected by obstructing objects such as buildings and trees, and influenced by the relative location of sound source and receiver, type of intermediate ground and meteorological conditions. Computation of sound... (read more)

2007-08-11 12:00:00

Automated Modelling of Tunnels

From Point Clouds to Cross-sectional Dimensions

Tunnels must be regularly monitored to meet safety requirements and to prevent excessive deformation or displacement. Tunnels are currently monitored by measuring a few benchmarks using total stations or other surveying instruments. These techniques are effective and precise, but also slow and expensive. In the case of rail tunnels, for example, the regular train schedule is disrupted whenever land surveyors have to operate inside the tunnel. This article presents a novel automated method for the geometric modelling of tunnels from mobile Lidar point clouds with sub-millimetre precision. The models can be employed for maintenance, project management and enhancement of future... (read more)

2017-08-17 10:06:13

Modelling the Erechteion

Extracting Information from Very Large Datasets

Modern terrestrial laser scanners (TLS) generate between 10 and 50 million 3D coordinates per minute: about 500Mbytes of data. Together with high-resolution images for texturing purposes, this is enough information to choke high-end PCs running commercial software. The National Research Council in Canada has developed a framework for extracting information from very large TLS and imagery datasets, an evolution demonstrated in the Erechtheion project. This monument has been modelled in 3D to a spatial resolution of 2mm. The fully textured 3D model containing 348 million polygons can be interactively visualised and analysed in real time. Creation of an accurate... (read more)

2009-12-04 11:26:58

Watershed Modelling in Kentucky

The recently completed Kentucky Watershed Modeling Information Portal (KWMIP), funded through a 750,000USD Co-operative Agreement with the US Environmental Protection Agency (EPA), is an innovative, standards-based data provisioning portal for watershed modellers in the Commonwealth of Kentucky, USA. The portal is integrated with the Kentucky Division of Geographic Information (DGI) web mapping services - KYGeonet (http://kygeonet.ky.gov), KYRaster and KYVector, served over state government LAN, and the US Geological Survey (USGS) StreamStats (http://streamstats.usgs.gov/html/idaho.html). It uses data from the Kentucky Climate Data Generator portals and the EPA’s Environmental Information Exchange Network (EIEN) and STORET (STOrage and RETrieval) repository for water-quality, biological and... (read more)

2006-11-20 12:00:00

Propagation Modelling Accuracy

Mentum and Intermap Technologies, USA, have entered into a collaboration for the delivery of a new generation of height-attributed land-use geodata that addresses the propagation modelling needs of the wireless industry. The telecom-grade product, Cityscapes HD, offers an unmatched level of X, Y and Z accuracy at a price point that enables network operators to manage the large geographical areas required by today's wireless networks. Cityscapes HD is offered at a native resolution of 15m and is available immediately in the USA, Western Europe and parts of Asia. Cityscapes HD accurately includes the height of vegetation and man-made structures... (read more)

2011-12-13 09:51:25

Long Live Modelling!

An Assessment of the LADM from the Cadastre 2014 Perspective

The Land Administration Domain Model (LADM) makes a significant contribution to understanding the importance of data modelling in the domain of land, land administration and land management. The ‘Cadastre 2014’ vision of the International Federation of Surveyors (FIG) stated back in 1998: “Cadastral mapping will be dead! Long live modelling!”. While one might think that this message was clear enough, few professional colleagues took it seriously. The editorial team of the LADM were the first to undertake action to get to the bottom of this important issue. Now that the LADM has become an official ISO standard, that statement is... (read more)

2013-07-09 04:47:47

GIS for Hydrological Modelling

Gagetown Hydrologic Model

Estimating rainfall discharge is difficult in large catchment areas with varying topography. This leads to widespread inadequacy in culvert design, with resultant damage to these and other drainage infrastructure during storms, when water runoff is high. The authors developed three ArcGIS-based hydrological models which accurately estimate rainfall discharge for storms that occur anywhere between once every two weeks up to once a century, enabling improvements in culvert infrastructure design. The test results prove the potential for GIS to aid in the creation of highly accurate hydrological models. Although there have been hydrological models in existence for decades, we designed our... (read more)

2011-06-28 04:05:50

Reality Modelling Goes Mainstream

At Bentley System’s annual conference for infrastructure thought leaders, CEO Greg Bentley presented a keynote speech. He stated that since Bentley Systems’ acquisition and assimilation of ContextCapture software in 2015, the proliferation of reality modelling across users’ projects – and across Bentley’s software portfolio – guarantees that it will become a mainstream contributor to infrastructure project delivery and asset performance. Reality modelling describes the potentially continuous capture of infrastructure assets’ as-operated conditions for processing into engineering-ready reality meshes, and their 'enlivening' for immersive interaction. To date, reality modeling has processed digital photos acquired from ground-level and/or aerial photography, and in particular from... (read more)

2016-11-02 10:16:39

Infrastructure Modelling Software

Autodesk's new Infrastructure Modelling software products facilitates users in utilities, telecommunications organisations and government agencies improve the design and management of their infrastructure. Autodesk's portfolio of products - including AutoCAD Map 3D 2010, AutoCAD Raster Design 2010, Autodesk MapGuide Enterprise 2010, and Autodesk Topobase 2010 - provide users with a solution for designing, visualising, simulating and analysing infrastructure assets and development plans. In a recent live webcast, Jay Bhatt, Autodesk senior vice president for AEC Solutions, addressed technology's critical role in the design and management of infrastructure. Autodesk Infrastructure Modelling technologies facilitates aggregating multiple sources of data from... (read more)

2009-03-09 03:34:00

REDD Deforestation Modelling Video

Clark Labs of Clark University has added a new video to the video series on its website. This latest video, entitled REDD Deforestation Modelling with Land Change Modeller in IDRISI, introduces the new REDD modelling feature tool included in the latest release of IDRISI, the Selva Edition. This video demonstrates how to model baseline land cover change and to predict future scenarios, as well as how these scenarios will impact projected GHG emissions through the implementation of a REDD project. A REDD project proposal, or the Project Design Document submitted to the Verified Carbon Standard (VCS) Organization, requires maps and... (read more)

2012-03-05 10:31:13