Developing a Method Using Field Surveying Techniques and Instruments to Create 3D Terrain Models Faheem Muhammad Office of Science, Science Undergraduate Laboratory Internship (SULI) Savannah State University SLAC National Accelerator Laboratory Menlo Park, CA August 13, 2012 Prepared in partial fulfillment of the requirements of the Office of Science, Department of Energy s Science Undergraduate Laboratory Internship under the direction of Georg Gassner & Catherine LeCocq at (SLAC) National Accelerator Laboratory. Participant: Signature Research Advisor: Signature
TABLE OF CONTENTS Abstract 1 Introduction 2 Instruments and Method 3 Results 5 Discussion and Conclusions 6 Acknowledgments 7 References 8 Figures & Graphs 9
Abstract Developing a Method Using Field Surveying Techniques and Instruments to Create 3D Terrain Model. FAHEEM MUHAMMAD (Savannah State University, SLAC National Accelerator Laboratory, Menlo Park, CA 94205). My research involves developing a method using field surveying techniques and instruments to create 3D terrain models. The instruments involved in the method includes the Zoller and Froehlich (Z&F) Imager 5006i 3D Laser Scanner, Leica GPS Real Time Kinematic System (RTK) and Cyra Targets. The software utilized is the Z&F Laser Control, LFM Modeler, LFM Server, MicroStation V8i, Matlab, Surfer, and Arc Map. The first step is learning techniques to operate the Z&F 3D Laser Scanner, Leica GPS RTK and the computer software. The second step is land scouting which involves going in the project area to select the best position for the scanner. The third step is using the Leica GPS RTK to determine the eastern, northing and height coordinate points of each selected position for the scanner and targets setup. The fourth step is to setup the Z&F 3D laser scanner and targets on the selected coordinates in order to determine the unknown position of the scanner in the project area. The fifth step is using the scanner to perform scans on the multiple selected coordinate points of the project area. In total there were fifteen scan positions needed to capture the entire project site. The sixth step is using the Z&F laser control for scan registration. Scan registration involves tying all the data from the15 scan together based the scanner location in order to create a files that allow a 3D panoramic view of your project site. The seventh step is using MicroStation, LFM Modeller & Server to model the scans in order to create the 3D model of the entire project area. Following the creation of the 3D model the eighth step is running Matlab, Surfer, and ArcMap computer software to use data analysis and numerical computation to generate contour lines to show where the land differs in elevation, which in total creates a topographical map.
Introduction The purpose of this research is to develop a method based using surveying techniques and instruments to create a 3D terrain model of small project area. If the method is successful the the same method will be applied to create a 3D Model of SLAC National Accelerator Laboratory. This research help predetermines what, where and how and structure can built in a project area. The Zoller and Froehlich (Z&F) Imager 5006i 3D Laser Scanner will be used to create 3D scans based off positions in the project area. The Leica GPS Real Time Kinematic System (RTK) uses satellite navigation to determine coordinate points for scanner and target positions. Cyra targets are used to mark predetermined coordinate points by the Leica GPS and used for scan registration. The computer software involved includes the LFM Modeller & Server software used for scan processing and the Z&F Laser Control software used for scan registration. Then ArcMap, Surfer, and Matlab are used for numerical analysis to generate contour lines and MicroStation is used for CAD object modeling. The developed research method involves first utilizing the Leica GPS to determine coordinate points for target and scanner locations in our project area. When the points are measured the 3D laser scanner and targets will be setup and scanned around the project area. When the area is completely scanned, scans are used in computer software to model, analyze, register, and process scan data in order to create a 3D topographic map of project area. The topographic map will display all the dimensions of the land and all the objects in the project area. The main purpose of this research is to create and utilize a surveying method to create a small topographic map of the project area.
Instruments & Methods This section included the instruments and the developed method used for this research. included the Zoller and Froehlich (Z&F) Imager 5006i 3D Laser Scanner, the Leica GPS Real Time Kinematic System (RTK), position targets, the Z&F Laser Control Software, the Bentley MicroStation V8i software, the LFM Modeller software, LFM Server software Matlab, Surfer and Arc Map to generate contour lines to form a 3D topographic map. The Z&F 3D laser scanner is a tool that is used in the surveying field. The Z&F uses a laser to collect data points; the laser rotates in a horizontally 360 and 310 degrees vertically at a rapid pace; The Z&F 3D Laser Scanner scans 1,016,727 Pixel/Second, collects 800 million points per scan, reaches up to 79 meters in distance and completes a scan in the matter of minutes. The Z&F 3D laser scanner is the prime instrument choice, because it performs high resolution scans in 3 dimensions at a fast rate. This scanner will allow maximal coverage of a larger area in a short amount of time. [Fig1] In order for the scanner and scanning process to work properly, 6 unknowns need to be solved for. The 6 unknowns are determined by location and the orientation of the scanner. We measure three points in the area for one scan; two for the targets and one for the scanner, to solve for the 3 unknowns locations of the scanner. The Z&F scanner is set up over a point using a tripod and then leveled to the eastern, northern, and heights to determine the orientation of the scanner. The Z&F scanner is positioned to collect data points for maximum possible area. The scanner is position this way in order to limit and reduce the number of scans one can use to complete a project area. The LEICA SR530 Geodetic RTK Receiver is a land surveying instrument that determines the eastern, northern, and height coordinates in meters for the scanner positions. A
point is determine by measuring the time it takes the satellites signals to reach the GPS receiver on earth (1). Real Time Kinematic (RTK) is satellite navigation technique used in a land survey based on the use of the LEICA SR530 Geodetic RTK Receiver measurements of the GPS signals where a single reference station provides the real-time corrections, providing up to centimeter-level accuracy(2). Parker Krylon nails or PK nails are thick nails with indentation in the middle of its head that are driven into the asphalt. The PK nails serve as a place marker for the Leica GPS RTK to set into when it s time to determine the easting, northing, and height coordinate of a point. For object modeling, image processing, scan registration, and data analysis computer software such as Z&F Laser Control, LFM Modeller, LFM Server, MicroStation V8i, Matlab, Surfer, and ArcMap are used. The LFM Modeller & Server software used for scan processing, Z&F Laser Control software used for scan registration, and we use Matlab, Surfer, and ArcMap use for data analysis, image processing, test and measurements, and numerical computation to generate contour lines for 3D Topographical Map. The complete method involves using the Leica GPS RTK to determine eastern, northern and height coordinate points for scanner and target locations. Second we perform scans using the Z&F Imager 3D laser scanner at selected regions in the project area in order to reduce the number of scans used for a project are but maximize the amount of data. Third scanner data is process, registered, and model by LFM Modeller, LFM Server, Z&F Laser Control Software, MicroStation V8i software to create a 3D terrain model. Fourth generate contour lines using ArcMap, Matlab, and Surfer to apply to 3D terrain model which will form a 3D topographical map of the area.
Results The goal of my research is to develop a method that uses the Z&F 3D laser scanner, the Leica GPS RTK, position targets, and Bentley MicroStation V8i, LFM Modeller, Z&F Laser Control software, Surfer, ArcMap, and Matlab software to generate contour lines to create a small three dimensional topographic map of a selected region of land. [See Fig 2].The method was successful, but the end result was not a three dimensional topographic map. Instead the end result is a scan overview of the selected land region. A scan overview is the collection of 15 scans locations and coordinates which were renamed to FM001, FM002, FM003, FM006, FM007, FM008, FM016, FM022, FM023, FM028, FM029, FM031, FM036, FM038, and FM043 to organize the data. The registered scans are tied together as one which shows 3D data points collected by the 3D laser scanner in a low resolution pixilated scan photo. [See Fig 3] During the scan registration, we tried to register all 15 scans at once using the laser control software, but the software had a glitch which causes the program to crash. So we had to register the scans one by one in order to complete the registration process. After the registration process was complete, a 3D model of the project area was displayed, that showed all 15 scan positions. [See Table 1] The scan overview allows me to see the entire area in a three dimensional aerial view. In Figure 3 shows the exact location of the scanner positions, the area scanned, the roads, the buildings, the trees, and the dimensions of the land. In the scan overview, we notice two important blind areas, where the scanner could not collect good data points due to bad positioning of the scanner which resulted in a blind spot. The second blind spot is a portion of the back right hill that has fewer data points because the setup of scanner was position at a bad
angle. However, the scan overview did display data points of equal elevation in the parking lot and on hills where contour lines could be created. In order to create the contour lines for the scans, the buildings needed to be remove from the scan so that the contour lines won t be generated on the buildings, but only on the grass and asphalt to show all the different elevations of the land the project area. [See Fig 3.] Discussion & Conclusion My initial research project was to create a method using the Zoller and Froehlich (Z&F) Imager 5006i 3D Laser Scanner, the Leica GPS Real Time Kinematic System (RTK), position targets, the Z&F Laser Control software, the Bentley MicroStation V8i software, LFM Modeller software, LFM Server software, Matlab, Surfer and ArcMap to generate contour lines to form a 3D topographic map of a selected land region. The end result of my research is a three dimensional scan overview that shows the exact location of the scanner positions, the area scanned, the roads, the buildings, the trees, and the dimensions of the land area in a detailed low resolution pixilated scan photo. The scan overview also displays data points of the selected land region that can be used to create contour lines which can be formed into a three dimensional topographic map. We were not able to process where contours lines because of time. For future research this method of surveying could be used to create a 3D topographic which is useful to engineers, because it provides full detail layout of a land region in three dimensions, which highlights the different elevations of a land region. The map can be determine how, where and what can build in the land.
Acknowledgements I would like to thank the Department of Energy for providing the Summer Undergraduate Laboratory Internship (SULI). I would also like to that the SLAC National Accelerator Laboratory for being the host laboratory for the research I conducted. I would also like to thank my mentors Georg Gassner and Catherine LeCocq for providing interesting research and for selecting me to work with the Alignment Engineering Team at SLAC. I would also like to thank Michael Gaydosh and Hans Imfield for teaching me how to use the instruments.
Reference Page (1)(1999). GPS Basics, Introduction to GPS (Global Positioning Systems) Version 1.0. Switzerland: Leica. (2)WIKIPEDiA. (2012, August 16). Retrieved August 16, 2012, from WIKIPEDiA: http://en.wikipedia.org/wiki/real_time_kinematic
Scan Position Easting Northing Height FM001 1849269.791 603198.861 96.073 FM002 1849285.545 603225.272 94.605 FM003 1849317.016 603233.820 92.118 Table 1 Represents XYZ Location Coordinates Points of Scanner Locations in Project Area FM006 1849305.073 603157.148 91.178 FM007 1849281.757 603166.417 91.428 FM008 1849263.003 603171.066 93.663 FM016 1849316.425 603215.154 91.072 FM022 1849337.668 603202.184 90.959 FM023 1849340.903 603170.952 91.196 FM028 1849289.436 603184.925 91.185 FM029 1849299.348 603203.361 91.088 FM031 1849242.952 603198.955 95.368 FM036 1849260.098 603118.534 95.084 FM038 1849319.960 603129.437 95.302 FM043 1849344.309 603155.945 95.184 Figure 1 Represents Scanner & Target Locations In Project Area
Figure 2 Represents 3D Scan Overview of All Registered Scans Of Project Area