A 1.772Mb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE
In early September 2011, Global Infrastructure Surveys (GIS), in conjunction with Rapid Survey Solutions (RSS), used Topcon’s IP-S2 mobile mapping system to rapidly and efficiently map flood-affected areas in central Queensland for riskassessment purposes.
Much of the state of Queensland (in Australia’s north-eastern coast) was hit by devastating floods in late December and January of this year, resulting in considerable loss of life, along with damage to essential infrastructure, along with homes and buildings.
Central Highlands Regional Council (CHRC) is based around the town of Emerald, located in central Queensland’s coal-rich Bowen Basin–and one of the regions particularly badly affected by the floods. Mining in the region has still not completely recovered.
The council contracted GIS and RSS to map Emerald so it could extract floor levels for every house for future flood management measures, which involved surveying a total street length of around 450 km.
It is primarily using the data captured by the IP-S2 for risk assessment purposes, allowing it to know where existing house floor levels are for future flood management, as well as planning of new buildings and the floor levels the council would require to minimise the chances of flood damage.
Topcon’s IP-S2–which is sold and supported in Australia through Topcon’s distributor Position Partners–allows users to map, log and locate all objects along any roadway, rail reserve or construction right-of-way, with accuracies of 30-50 mm, at distances of up to 50 m–all within posted on-road speeds.
The IP-S2, which is vehicle-mounted and works off a standard 12-volt power connection, combines dual-frequency GNSS signal tracking and positioning and inertial measurement to integrate laser scanning and high-resolution digital imaging.
Using laser scanners and cameras, the data collected is integrated and timestamped, allowing accurate combination of LIDAR point cloud information and digital imaging data, to build 3D models of the areas covered.
In mapping Emerald, the IP-S2 vehicle, driven by RSS co-director Nick Nolan, was able to cover every street in the council’s prescribed area over a very short period, giving the council the ability to capture data on the floor levels of a most houses in the town.
Once the data has been completely processed and analysed, the council will know the floor level of each house within the surveyed area–for example, whether it is a "Queenslander" style house with a raised living area above the surrounding ground, or a more modern design with a concrete slab on the ground, or anything in between.
In addition, CHRC purchased a copy of Topcon’s Spatial Factory, which allows viewing, analysing, and extracting features from processed IP-S2 datasets. Shortly after the devastating floods hit Queensland, Lyle Harman, the CHRC’s recovery co-ordinator, contacted Les Whalley, managing director of GIS.
"The council was interested in obtaining the floor level of the houses in the affected areas of town primarily to allow better flood management and assessments on how future floods would impact various parts of the town," said Les.
"The council needed a rapid solution; we’d previously worked in conjunction with RSS and we knew the capabilities of the IP-S2 technology–and so we recommended this system to CHRC.
"Not only was the IP-S2 exactly what they were after, it also saved considerable time and money," he said.
RSS co-owner Brad Chambers said that CHRC saw potential in the IP-S2 captured data, not only for meeting its immediate needs in post-flood studies of floor levels, but also for the data-mining of information captured for other purposes.
"One of the big benefits that they could see out of this system over any other, was that it was able to generate photographic images as well as threedimensional survey detail and because the information captured was quite rich, they could data-mine additional information later on–and that was really the key to their deciding to go ahead with it," said Brad.
"Basically, we left Melbourne on the Friday night, drove up the centre of the country and landed there on Sunday in time to do a reconnaissance mission around the town to work out the best way to attack it.
"We had a base station set up so that we split the town into six areas, of fairly equal size and bounded by a major road, giving us some overlap with the LIDAR data.
"For each one of those areas, we had a base station and recorded all the positions of the survey marks in the area," he said.
"This involved placing numerous ground control points–something which was far more time consuming than the actual IP-S2 Survey, and which needs to be taken into account on any project requiring tight positional tolerances.
"Each one of those was recorded by GPS base and rover, then later on was imported into Spatial Factory so that we could register all that control in the IP-S2 run; that ensured that we got the accuracy that the council required for level control and position," Brad said.
For the short period of time the RSS team was in Emerald it collected imagery and LIDAR data for around 450 km of streets. The remainder of data was processed on its return to Melbourne.
According to Brad, one challenge the team faced was situations where houses were behind high fences or trees.
"The problem is that if you can’t see the house, you can’t see the floor level.
"However, we were recording images every 3 metres, which was a lot more than we normally would and that gave us the chance to see up driveways and down in between houses.
"So, if we can actually see the house and the scanners can get some points on the building, we can then interpolate off the points and off the images as to where the floor level would be," he said.
Once the data had been captured and processed, the council used Topcon’s Spatial Factory to analyse it.
By going through each image and clicking on the floor, its survey team can create points for CHRC’s GIS system.
"Each point has an X, Y, Z position, which effectively gives the council an address for each of those houses; then, once it is in the GIS, it can run a report function on any of the attributes collected," said Brad.
"That has allowed the council to take the data that we and RSS supplied to them and then process and analyse everything themselves without us having to extract it for them."
According to Les, the capabilities of the IP-S2 allowed the council to capture far more data, at a far lower cost, than it had originally planned.
"Initially for this project, the council wanted to just map flood-affected areas, but due to the cost-effectiveness of the IP-S2 and its speed of operation, the council was able to map the entire town, capturing data for a wide range of purposes that it can use for many years to come," he said.
Photos and screen captures courtesy of Rapid Survey Solutions. Aerial photo by Daryl Wright.
Further information Global Infrastructure Surveys: ph (07) 5520 3304 email enquiries@globalsurveys.com.au.
Further information Topcon IP-S2: Position Partners, ph 1300 TOPCON (1300 867 266), email info@positionpartners.com.au.
Mark Cherrington has been writing about the construction, mining and survey industries for more than 30 years. He was editor and later publisher of Australia’s The Earthmover & Civil Contractor magazine for nearly 20 years, and for the past decade has been providing writing, marketing and other services across a range of related industries through Spitfire Communications Pty Ltd.
Sidebar:
Mobile Mapping And Natural Disasters
By Richard Rybka, RLA Topcon Positioning Systems
Natural disasters–earthquakes, tsunamis, floods, tornados, hurricanes– have become a recurring topic in the global news of 2011. Not only has the world seen an increased frequency of these events over a compressed period of time, but also experienced record breaking intensities.
Vehicle-mounted mobile mapping systems are poised to make great improvements in preparing for and responding to natural disasters. These advanced systems can quickly gather essential information from the safety of a vehicle, far surpassing conventional data collection methods in efficiency and comprehensiveness.
Pre-event baseline mapping of developed areas is invaluable information for post-disaster comparisons and validating insurance claims. Take the City of Galveston, Texas as an example. This outlying island sustained a direct hit by Hurricane Ike in September of 2008. Several days advance notice of the storm were available based on course predictions by the NOAA’s National Hurricane Center.
Driving the 370 miles of Galveston’s roads with a mobile mapping system like Topcon’s IP-S2 would only take 14.8 hours at an average speed of 25 miles per hour. The results–360 images and 3D colorized LiDAR point clouds–could be used as a near-realtime visualization tool to plan emergency response as well as document pre-event conditions. A detailed application study of how mobile mapping can be used for Disaster Response Planning can be found at: http://www.topconpositioning.com/sites/default/files/files/DisasterResponsePlanning.pdf
Post-event periods present additional opportunities for the application of mobile mapping. Aerial LiDAR and imagery are now widely used to get a bird’s eye overview of stricken areas. However the information obtained by these technologies lacks the street level detail needed for comprehensive assessments.
The objective of post-disaster mapping is to assess the extent and nature of damage as quickly as possible. Roads are likely to be impassible, blocked by debris or flooded. A compact mobile mapping system like the IP-S2 can be mounted to an ATV, enabling access to areas that cannot be reached with a car or truck. To view an example of the maneuverability that an ATV-mounted mobile mapping offers, take a look at this YouTube video: http://www.youtube.com/watch?v=lWgHLiahoCA&feature=related
During reconstruction, mobile mapping systems can be deployed on a periodic basis to record and document progress of clean up and restoration operations. Depending on the location and accessibility, they can also be used to map debris stockpiles for volume calculations.
The story of Global Infrastructure Surveys/Rapid Surver Solutions’ project for Central Highlands Regional Council (CHRC) in the state of Queensland, Australia–which faced devastating floods and a cyclone (hurricane) earlier this year, gives us a glimpse of how mobile mapping is emerging as an important tool for disaster planning and response.
A 1.772Mb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE