Using LiDAR Data for Terrain Analysis: Tools and Techniques, Slides of Water and Wastewater Engineering

Download Using LiDAR Data for Terrain Analysis: Tools and Techniques and more Slides Water and Wastewater Engineering in PDF only on Docsity! Basics of Using LiDAR Data 21 3D Analyst  ESRI Extension – Additional cost  Specifically designed for elevation data  3D visualization  Creating & working with TINs  Cross-section tool ArcHydro  Free Extension for ArcGIS (Maidment)  Suite of tools for geospatial hydrology  Semi-complicated install  Terrain analysis focused on stream and watershed delineation  Tools for analyzing sinks and reconditioning DEM  AGREE Tau DEM  Free toolbox for ArcGIS 9.3 (Tarboton)  Easy install  Specialized terrain analysis tools focused on stream and watershed delineation  Tools not found in the standard ArcGIS extensions or ArcHydro  D-infinity flow direction Whitebox GAT  Free stand alone program (Lindsay)  Open source  Fairly robust suite of terrain analysis tools  Handles LAS data (LiDAR)  Many hydrologic analyses  Uses Python as native language Getting Ready for LiDAR – Hardware  Bigger is better  Workstations ○ Duo or Quad Core ○ > 3.0ghz ○ > 4Gb RAM ○ 256 RAM Display OPEN GL  High Speed disks – storage is cheap  External hard drive for backup LiDAR Representations Docsity.com Basics of Using LiDAR Data 22 LiDAR Representations Point Cloud Triangulated Irregular Network (TIN) Raster – DEM Vector – Contours Terrain Bare Earth Filtering Bare Earth vs. First Return LiDAR Representations Point Cloud Triangulated Irregular Network (TIN) Raster – DEM Vector – Contours Terrain TIN Triangles Hillshaded and Colored by Elevation Credit – Tim Loesch - MNDNR TIN – With Breakline enforcement Docsity.com Basics of Using LiDAR Data 25 MN LiDAR Data Delivery What Data Do People Use?  Primary use products ○ Raster Digital Elevation Model ○ Contours  Most consumers don’t bother with the raw LiDAR data ○ Not a lot of tools available but this list is growing ○ ArcGIS extensions are now available to read LAS format LiDAR data  Derived products from LiDAR is a growing research field MN LiDAR Data Delivery Format MN DNR FTP Site  ftp.lidar.dnr.state.mn.us File Geodatabases Data Organization  Tiling Scheme ○ County ○ Project ○ Quarter quarter quarter quad (1/16th of a quad) (Raw) Not all data types tiled the same  Size limitations Where To Get It What Data Type? What Geographic Scale? MN DNR FTP LiDAR Quick Download Guide FTP Download Site County DEM Contours Lidar.state.mn.us/ data/county Smaller DEM Contours Bare Earth Points Lidar.state.mn.us/ data/raw/county MN LiDAR Data Delivery Format File Geodatabases Data Organization  Tiling Scheme ○ County ○ Project ○ Quarter quarter quarter quad (1/16th of a quad) (Raw) Not all data types tiled the same  Size limitations Docsity.com Basics of Using LiDAR Data 26 MN LiDAR Data Delivery Format MN DNR Interactive Download and Viewer  Beta Viewer Available April 1st  Data Services Available May 11th  Mobile App Available June 1st MN LiDAR Data Delivery Format Things to know…  Use third party FTP Software - Filezilla  Know what you want before you download  Interactive web download page coming in near future  RTM – Read the Manual! ○ Several helpful Readme’s MN LiDAR Data Delivery Format - LAS Files LAS – Common LiDAR Data Exchange Format  Industry Standard ○ Easily transferred from system to system ○ Less volume and more easily transferred than ASCII  Retains flight information and instrument parameters ○ GPS, IMU, Laser Pulse Range  Current version is LAS 1.1 (5/05) ○ 1.2 has been proposed and in final review ○ 2.0 has been proposed Delivery Format - LAS LAS files  Stores a variety of point information ○ Number of returns ○ Return Number ○ Intensity ○ X,Y, Z values ○ Scan Direction ○ Classification ○ Scan Angle Rank ○ GPS Time LAZ files = Compressed LAS files Visualization Credit – Tim Loesch - MNDNR Visualization Lidar data can be visualized a number of ways  Shaded Relief images can reveal very subtle relief ○ Especially with high detail data ○ Helpful for data validation and looking for anomalies and errors in the data  3-Dimensional viewing  Cross-sections  Contour generation  Triangulated Irregular Networks (TIN) Docsity.com Basics of Using LiDAR Data 27 Shaded relief imagery 3/27/2012 MN GIS/LIS Fall Workshops Credit – Tim Loesch - MNDNR 3/27/2012 MN GIS/LIS Fall Workshops Credit – Tim Loesch - MNDNR Sinkhole 3/27/2012 MN GIS/LIS Fall Workshops 2006 color NAIP airphoto 3/27/2012 MN GIS/LIS Fall Workshops Sinkhole 3/27/2012 MN GIS/LIS Fall Workshops Sinkhole – Cross-section 3/27/2012 MN GIS/LIS Fall Workshops Docsity.com