The use of a laser rangefinder attached to a pocket PC to capture and analyze 3D digital geologic data in the field– a case study – Preston Railroad Cut, Texas Mohammed Alfarhan firstname.lastname@example.org Carlos Aiken email@example.com Xueming Xu firstname.lastname@example.org John Thurmond Objectives • Initial proof of concept of digital mapping. – Integration of GPS, lasers and portable computers. – Integration of laser gun data and fast scanner data • Digital terrain by GPS and lasers. • Real time strike and dip determination. • Initial test of oblique photography. Study Area Location Preston Canyon Preston Canyon, Austin Chalk, Plano Laser Mapping System Laser gun using Laser gun Laser gun memory cards attached to attached to laptop pocket pc Laser rangefinder Encoder Portable computer Customization of ArcPad • The Geological Survey of Canada was a pioneer in developing data logging geology with their GanField program using ArcPad installed in pocket pc with an interface to capture the data using GPS • In cooperation with the GSC we are modifying that software using ArcPad 7 attached to a laser rangefinder to capture the data in real time digitally and display it in the field such as used in UTD’s Cybermap. Comparison between Laser Mapping System Laser gun using memory Laser gun using laptop Laser gun using pocket pc card (ArcPad & Terrasync 1. Need holder to help 1. Can’t display the data carrying the laptop 1. Light and easy to carry captured. 2. Can display the data 2. Can display 2D data 2. Need post process the captured captured in the field data. 3. Can shoot continuous 3. Can shoot single shot 3. Can shoot single or (only laser atlanta or only continuous (only laser MDL) and single shot 4. Can save the data as atlanta or MDL) 4. Save the data as GIS GIS format format or text format 5. Can’t process the data no need for post in the field. processing 5. Can display the data as 2D or 3D in the field. 6. Can process the data and drape digital photographs on the 3D model in the field New generation of laptop $1700.00 - $1900.00 specifications 1GHz Transmeta Crusoe 30GB hard drive (shock-mounted) 512MB DDR RAM Dimensions: 4.9" x 3.4" x 0.9" Weight: 14 ounces 800 x 480 W-VGA 5" transflective display (indoor/outdoor readable) 3D accelerated graphics with 8MB of video RAM QWERTY thumb keyboard with mouse buttons and TrackStik 802.11b wireless Bluetooth wireless Example OCP, Sony CyberMapping Design Flowchart Laser rangefinder Encoder Portable computer Main Window Interface of CyberMapping Software 3D perspective view using CyberMapping 3D perspective view using ArcScene Map view of the mapping of layer and faults Continuously shooting Topcon total station North side of cut, vertical section mapped by GPS controlled Topcon reflectorless laser mapping. LPM and Riegl Z360 Scanner Riegl Z360 LPM Point cloud taken by fast scanner Triangulated Mesh Surface cleaning (in Polyworks) • In draping photo the single most time consuming part of entire process (90% of time). – Filling the holes (because of scan shadow) – Correct triangles Digital photographs draped on triangulated mesh Failed attempt to drape oblique photo onto terrain by rubbersheeting with ESRI software Orthophoto draped onto terrain The integration between laser gun data capture and fast scanner photorealistic 3D model The integration between laser gun data capture and fast scanner photorealistic 3D model The integration between laser gun data capture and fast scanner photorealistic 3D model The integration between the data taken by laser gun and draped orthoquad Converting the points to lines and surfaces Converting the points to lines and surfaces Converting the points to lines and surfaces Converting the points to lines and surfaces 3D Digitization of zoom of mesh model texture mapped with photography Digitized layer Surface fit to digitized interface to define 3D feature Digitizing the features using open scene graph Conclusion The integration between laser gun and fast scanner is very useful. ArcPad has limited features and the new generation of the handheld laptop and CyberMapping and ArcGIS installed in it will replace the pocket pc and ArcPad. Customization is the key to make capturing the data easier and faster. Douglas Walker in University of Kansas was pioneer in customizing ArcView and ArcGIS software. In the future work we will cooperate with Walker in UK to build an extension that will allow ArcGIS capture the data using a laser gun and add more customization to ArcGIS.