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Mapping Geology for Safe Road Expansion
In 2014 Maptek surveyed a road corridor and surrounding cliffs in Oman to help safely design the roadway expansion. Mountains rising from the plains of Ras al Khaimah made it virtually impossible to reach the city of Khasab in the exclave of Oman until development of a coastal road from the United Arab Emirates opened Khasab to the world.
The highway runs alongside a sheer coastal cliff. Large overhanging rocks are susceptible to falling, particularly following rainfall. A planned upgrade prompted officials to commission a study to ensure the new design would prevent rock falls and improve road safety.
The challenging regional geology meant that mapping structures and assessing stability was crucial to gain a better understanding of the cliff faces. A MaptekTM I-SiteTM 8810 laser scanner was used for geological mapping and geotechnical data acquisition. Surveying was fast and safe, with 3 kilometres of road scanned each day despite the difficult access. The I-Site laser scanner was mounted on a crane to capture data on high faces where the offset was even tighter.
Cliff walls were up to 100 metres high. Traditionally, a team of climbers would scale them and use a handheld compass to map the rock faces. This was neither fast nor safe. Mounting the laser scanner on a vehicle allowed the survey crew to scan from a safe distance, away from large overhangs.
The original project scope required rose diagrams for each of the thousands of rock faces along the cliff to develop a regional geological report. Topographic surfaces of the road and cliff face were generated in I-Site Studio software to create a slope map for identifying steep areas. Stereonet analysis allowed for detailed geotechnical evaluation.
After data collection finished the contractor requested cross-sections of the walls and road, along with volumes of rocks at high risk of coming loose. Traditionally, this would have required time-consuming new surveys. The I-Site 8810 point cloud data was easily modelled and exported as cross-sections. This information helped determine where mesh or shotcrete would be required to stabilise surfaces.
Queens University, Dublin Laser Scan to BIM Project
Precision Surveys Limited performed the first outsourced high quality laser scan to BIM project for Queens University Campus, Belfast, Ireland on "The Peter Froggatt Building."
The survey required over 250 colored medium resolution scans using the Leica C10 and Leica P20 scanners and precise control was achieved with the use of the Leica Viva Total station.
Deadlines were extremely tight for this project, Precision Surveys had a two week window during the university break to complete the project to produced Leica trueview models for each floor in Color. They had to work closely with a contactors team as every ceiling tile had to be removed before being scanned. This was an important part of the project as the M&E were using this as a base to redesign their systems.
Precision Surveys Limited is a family run company and one of Ireland’s longest serving Survey Practices started up by Ray Buffini MD.
Precision Surveys Limited offers a comprehensive consulting service orientated towards providing land related information to both public and private sector clients throughout Ireland. For almost 40 years, the company has been successfully satisfying customer requirements in the domain of surveying, engineering and legal disputes. It has more than 8,000 surveys completed which include building surveys, reference plans, legal and topographic surveys, laser scans, pointcloud to BIM, control and engineering surveys, taking in charge, layouts, etc. Their greatly educated and experienced land surveyors provide the highest quality of expertise at the best competitive rates.
For more information, contact: PRECISION SURVEYS LTD, Unit 7, Redleaf Business Park, Turvey, Donabate, Co. Dublin., T +353 1 8406252 , info@precisionsurveys.ie, www.precisionsurveys.ie, www. scantobim.ie
LiDAR and Orthoimagery Services, Municipality of Anchorage, Alaska
Merrick & Company was awarded a contract in April 2015 to provide LiDAR and aerial orthoimagery services for the Municipality of Anchorage, Alaska. The Municipality of Anchorage, through its collaborative GIS Center of Excellence, has engaged Merrick & Company to acquire public domain LiDAR and orthoimagery covering 1,000 square miles of the Municipality. Municipal departments led by the GIS Center contributed to funding the project. The USGS awarded the Municipality a 50% matching grant as part of the national 3DEP Program in order to complete the acquisition. The Municipality’s need for the LiDAR and orthoimagery project was driven by the need for updated elevation data and imagery. Municipal applications for the new datasets include emergency operations mapping, public safety response mapping, water/sewer utility support, planning, public works, watershed management, parks and recreation, property appraisal, port management, and others.
LiDAR and aerial imagery data acquisition was carried out in May 2015 and final deliverables will be provided in November 2015. The LiDAR data was collected with a Leica ALS70-HA to support two separate LiDAR density requirements. The aerial imagery was collected with a Leica DMC II to support creation of 0.5′ 1.0′ orthoimagery.
The area of interest for both LiDAR density regions are shown in Figure 1, with the red areas representing 4 pulses per square meter (ppsm) density, and the yellow areas representing 2 ppsm density. All LiDAR data adheres to the USGS LiDAR Base Specification 1.2 for Quality Level 2 (QL2).
Services under this agreement include collecting LiDAR and digital aerial imagery in order to produce a number of products including: tiled orthoimagery at 0.5′ (6") resolution, topographic contours, digital elevation models and 2D building outlines for the urban area, and an educational workshop regarding imagery and LiDAR for Municipal staff.
All products are to be delivered in ESRI ArcGIS version 10.2 geodatabase in compliance with the latest version of SDSFIE.
In addition, Merrick is working closely with the Municipality of Anchorage Survey Department to establish a survey control network for the entire area that can be used in future acquisitions and mapping efforts. Figure 2 shows the survey control provided by the MOA.
These datasets address important management issues because the Municipality of Anchorage is the largest city (300,000 population) in the state of Alaska, rapidly growing, and is in need of updated and accurate geospatial data to support many uses. Merrick & Company is providing the following services:
Color digital aerial imagery acquisitio
0.5′ Color digital orthoimagery
LiDAR acquisition
USGS DEM
LAS files tiled to MOA guidelines
Two-foot (2′) contours
GPS ground control & HICS features
SDSFIE
ArcGIS geodatabase
2D building outlines
An Imagery and LiDAR Workshop
Merrick & Company is a multi-disciplinary mapping, surveying, engineering, and architecture firm headquartered in Greenwood Village, CO. The company is celebrating its 60th anniversary this year. Please visit our website: to learn more about what we do. www.merrick.com/
DroneMetrex First UAV Designed Specifically for Photogrammetric Mapping
DroneMetrex is an Australian company specializing in high accurate photogrammetric mapping using TopoDrones. The TopoDrones are unmanned aerial vehicles (UAVs) specifically designed and built by DroneMetrex as a powerful photogrammetric mapping tool to collect regular, repetitive, rapid and accurate geospatial data for a wide range of industries including, but not limited to, civil engineering, roads and railroads, mining industry, agriculture, forestry, waste management and recycling, environmental applications.
DroneMetrex has proved to be the only UAV company to develop from the start the true drone mapping system based on photogrammetric principles and only then adapted it to an airframe. The TopoDrone-100 addresses all known systematic and random geometric errors (tip, tilt, yaw, forward and lateral motion, blur) from the start and eliminates them right at the point of capturing the data.
The TopoDrone photogrammetric mapping systems capture and process aerial data with unsurpassed mapping accuracy: 10mm horizontal and better than 25mm in height.
The TopoDrones are the only mapping UAVs in the world to feature simultaneously:
1. Unique Dynamic-stabilised Active Mount to ensure near-nadir position of each and every photo with no "crab" (yaw);
2. Calibrated full-format camera with focal leaf shutter and Zeiss lens;
3. PPK Direct Georeferencing Solution– mapping with no ground control;
4. Extended spectrum mapping–using the same camera and changing three separate filters the following types of imagery can be captured:
a. Natural colour;
b. NIR imagery;
c. Bathymetric–mapping under water;
Projects
Agriculture
In April 2015, for the first time in the UAV’s mapping history, DroneMetrex captured unsurpassed quality NIR data with the TopoDrone-100. From the one flight sortie vegetation analysis mapping was performed as well as accurate 3D contours/DTM mapping. The pixel resolution, data geometry and radiometric quality were unparalleled. DroneMetrex offered its Extended Spectrum Mapping (ESM) camera modification as an option with the TopoDrone-100. After ESM modification, the camera was supplied with 3 external screw-on lens filters. Using simultaneously the NIR filter and also high accuracy L1/L2/L5/GLONASS/COMPASS(BeiDou-2) PPK Direct Georeferencing Solution the TopoDrone-100 captured 3-band imagery, with the near infra-red band recording unparalleled radiometric quality and chlorophyll discrimination.
Civil Engineering
In August 2014, in South Korea, DroneMetrex demonstrated the Direct Georeferencing System and performed mapping of the golf course with no ground control. Accuracies were independently checked and verified: 4cm accuracy from the 4cm GSD imagery. At the end of the flight sortie, the TopoDrone-100 had to land on dirt during light rain. However, this provided no difficulties because the camera was protected by the TopoDrone’s unique protective door system.
Railroads and roads
Earlier DroneMetrex has performed a railway project in Australia. The TopoDrone-100 mapped 0,5 km on each of the four sides of the approach to the crossing intersection of the railway and the bitumen road with the unsurpassed accuracy: 2,5cm GSD aerial imagery with 25mm absolute accuracy in height. The project was aimed at creating 3D "real world" for obscurity analysis when approaching an intersection from a train driver’s perspective, and from a vehicle driver’s perspective. Secondly, high accurate mapping was performed for future civil works involving repair as well as upgrading of the existing railway.
For more information, contact: DroneMetrex, 9A Crittenden Rd., Findon, SA 5023 Australia Tel: +61 (0)8 8243 1280 | Fax: +61 (0)8 8243 128 | E-mail: info@dronemetrex.com www.dronemetrex.com
Sanborn Aerial LiDAR Point Cloud for Nationals Park and the Pentagon
Sanborn performed aerial data acquisition services for the District of Columbia Office of the Chief Technology Officer (OCTO) in 2015. Our partner on the project was A. Morton Thomas & Associates, a Washington, D.C.-based engineering firm.
The project goal was to produce LiDAR, high-resolution (4 band) orthos, and high-resolution oblique imagery for the Washington, D.C. metro area. The restrictive nature of flight planning over the nation’s capital presented a unique challenge for the project, and Sanborn successfully completed on-time data acquisition for the project by deploying all three required sensors in one integrated flight.
Final acquisition included USGS QL-1-compliant LiDAR data (actual nominal point density collected was 40-80 points per square meter), aerial imagery for high-resolution 4-band orthos (2.7-inch resolution), and imagery for high-resolution oblique products (4-inch resolution). The samples included show LiDAR point cloud data for Nationals Park and The Pentagon.
For more information contact: Jason Caldwell, Vice President of Business Development and Sales, The Sanborn Map Company, Inc., 1935 Jamboree Drive, Suite #100, Colorado Springs, Colorado, Toll Free: 1-877-368-9702, jcaldwell@sanborn.com, www.sanborn.com, Twitter: @SanbornMap, Facebook: www.facebook.com/SanbornMapCompany
A 5.589Mb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE