Tim Loesch Minnesota Department of Natural Resources

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1 Tim Loesch Minnesota Department of Natural Resources

2 Agenda Status of State Project Where to get data What types of data are available How to download and retrieve information What to do after you download the data Examples of LiDAR Use

3 Remote sensing technology similar to radar, but uses laser light instead of radio waves Combined with GPS information a point cloud, a collection of X,Y,Z points (millions per square mile!) Precision and number of points depends on collect specifications Scanners can be ground-based, airborne, or spaceborne

4 LiDAR Data in Minnesota Available for large areas 52,000 square miles in the Public Domain High quality High degree of consistency

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6 Acquisition Initiatives Red River Valley International Water Institute Minnesota High Resolution Elevation Mapping Project Several County Collects Blue Earth, Chisago, Crow Wing, McLeod, Pine, Rice, Stearns, Wright Carver, Dakota, Goodhue, Ramsey, Scott Older data, proprietary Re-acquired as part of MN HREM

7 DESIGNING A RING DIKE LiDAR was used in the Wild Rice Watershed (Red River Valley) to accurately locate, size and align the structure, to estimate ring dike material quantities and total costs, and to meet permitting/mitigation requirements.

8 DESIGNING A RING DIKE The result during the 2009 spring floods

9 Minnesota Elevation Mapping Project Started with the USGS LiDAR Base Specifications V13 Draft Published February 22, 2010 Specifies minimum specifications for Federal and Federally funded LiDAR projects Collection Data Processing and Handling Hydro-Flattening Requirements Deliverables 2/21/2012

10 Data Deliverables All data are delivered in tiles based on 1/16 th of a USGS 1:24,000 scale quadrangle Roughly 3.25 square miles DNR_QQQ_ID Tile name field A good balance between file size and area Average LAS file size = 291 mb Average GDB file size = 5.6 mb 2/21/2012

11 Tile scheme 16 tiles per 24K quadrangle Data must fill tile no partials 2/21/2012

12 File Geodatabase Contents Contour_Data Feature Dataset Contours 2 contours (3D Polylines) Terrain_Data Feature Dataset Bare_Earth_Points bare earth points from LAS files (3D Multipoint) Hydro_Breaklines Edge of water breaklines (3d Polygons) DEM01 one meter DEM Buildings Building outlines generated from LAS

13 Products from the state collects include: LAS (Open standard format), classified Bare Earth points Rough building footprints Hydro Breaklines 1-meter DEM 2 contours 3-meter DEM hillshades

14 Hydro Breaklines

15 Building footprints Not required by state collect contract to be perfect Gives relative proximity and quantity Sometimes tall vegetation in flat areas is erroneously depicted as building

16 In ArcCatalog

17 LAS Files One per tile Full Point Cloud All returns all points Classifications 1 - Processed but unclassified 2 - Bare earth ground 4 Vegetation 6 - Buildings 7 - Noise (low or high) 8 Mass Points 9 - Water 10 Breakline Proximity 14 Bridge Decks All Points Bare Earth Ground Vegetation Buildings Mass Points Water 2/21/2012

18 What about existing data? Projected to UTM Zone 15 Vertical Units converted to meters Re-Tiled to 1/16 tile Reproject 3d shapefiles Scale 3D shapefile from feet to meters Recreate DEMs, Contours Published on ftp site

19 County Data Bundles Data have been assembled into county based bundles Mosaic all tiles that touch county Ease of use for county and other staff Assists with QA/QC Additional derived products ArcGIS 9.3 File Geodatabases

20 County Bundle File Geodatabase Contents ELEVATION_DATA.GDB Buildings Building polygons Contours Two foot contours DEM01 One meter DEM Mosaic DEM01HS Hillshade of DEM01 DEM03 Three meter DEM (rescaled DEM01) DEM03HS Hillshade of DEM03 DEM03Slope_degree Slope of DEM03 in degrees DEM03Slope_percent Slope of DEM03 in percent Hydro_Breaklines Edge of water breaklines qaqc table of tiles and statistics for data Tile_index index of tiles for county Validation_points survey shots used for QA/QC

21 In ArcCatalog

22 Data dissemination is a challenge Data volume is high 26,000 square miles = 1 tb of data Variety of data representations Contours, DEMs, LAS, etc Plethora of software formats CAD, GIS, Graphics Projections.? Lots of questions

23 County Area (sq miles) Mosaic LAS Geodatabase Total Douglas gb 56gb 21.5gb Faribault gb 76.5gb 16.5gb Jackson gb 75.8gb 18.2gb LeSueur gb 55.6gb 10gb Martin gb 91.5gb 17.3gb Nobles gb 71.3gb 20gb Pope gb 70gb Rock gb 51.5gb 12.5gb Waseca gb 41.5gb 7.91gb 52.68

24 LiDAR allowed staff to quickly assess the entire project area and select preliminary sites. On-site surveying determined which sites were optimum. Once selected, staff compared cut-andfill estimates using the computer model and on-site surveying (the figures were remarkably similar, within 3-7 percent).

25 Where to get Data DNR ftp access Server name - lidar.dnr.state.mn.us Pros Data is available Data is highly structured and consistent Can download vast quantities of data Cons Not entirely intuitive Must use ftp Client Must learn storage structures Not entirely fast

26 FTP Site contents \data all LiDAR related data found here \documentation documentation and instructions for site navigation \examples small lidar example datasets \tools tools for using LiDAR and Elevation data \training training materials \readme_first.rtf site documentation in text format \watchme_first.swf site documentation in video format

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28 Mosaiced Data Packets are found at: \data\county\<county_name> Elevation_data.gdb Tiled Data Packets are found at: \data\raw\<county_name> Geodatabase Folder LAZ Folder

29 Accessing LAS Data LAS files are stored as compressed LAZ files LAS -> LAZ Lossless Compression averages 90% This is a BIG deal Uses LASTOOLS LASZIP.EXE Command Line tool Compression and Uncompression

30 LASTOOLS An easy to use, lightweight and efficient set of tools for processing LiDAR data in LAS format Not a free set of tools but some parts ARE free License information can be found at: d/license.txt LASZIP compression software IS Free as is LAS2LAS

31 Scenario YOU are a technician who has to obtain LAS data for a Project Project is in LeSueur County at the intersection of State Highways 99 and 112 Convert data to ASCII X,Y,Z format for input into CAD How do I get there?

32 Using an FTP Client 1) Log into lidar.dnr.state.mn.us 1) Anonymous username and password 2) Change folders to: 1) \data\raw\county\leseuer 3) Download and View TILE_INDEX_MAP.PDF 4) Identify Tiles to Download 5) Change folders to 1) \data\raw\county\leseuer\laz 2) Find and download tiles of interest 3) Unzip to LAS Format

33 Need Tile

34 Download LAZ via FTP

35 Unzip using LASZIP tool

36 LASTOOL Capabilities LAS2TXT to convert LAS files to X,Y,Z ASCII format LAS2LAS to re-project data Clip Data to circles, squares and rectangles Filter data based on Classifications Class 2 (bare earth) is often too much information Class 8 (Mass Point) is a subset of Class 2 Can find tips for LASTOOLS at: \tools\lastools\las_file_processing_using LASTOOLS.pdf

37 Export to CAD as ASCII x,y,z file

38 Other CAD Options AutoCAD Civil3D can now read LAS files Classes 2, 8 make up bare earth Some users prefer to use Raster data to build surfaces Don t use Contours!

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40 Geodatabases if you are working with ArcGIS Once you ve found the Tiles you need Download from the county GEODATABASE folder gdb Ready to use in ArcGIS

41 If you want County Mosaic Data Go to the county folder of interest \data\county\lesueur Download entire folder ELEVATION_DATA.GDB Validation Report Ready to use in ArcGIS

42 Future Plans Simplify downloads using browser based front Provide options for: Project data Output formats (CAD, GIS) Output representations (contours, TIN, DEM, Points) Subset data (clipping and filtering) Expect availability in 2012 More Web Services Check out:

43 Future Plans Web and Smartphone LiDAR Viewer DEM, Contours, Terrain, Slope, Air Photos, Base maps User Defined Profile and Point Elevations PDF output

44 A great example. International Water Institute LiDAR Portal Pros Visual access via browser Intuitive interface that is easy to use Select and download Six representations instructions for downloading

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46 Training Opportunities Conservation Applications of LiDAR University of MN, DNR, BWSR Funded by LCCMR Nominal fee <$40 Six Class Series Basics of Using LiDAR Data Terrain Analysis Hydrologic Applications Engineering Applications Forestry and Ecological Applications Wetland Mapping

47 Training Opportunities Or search on Conservation Applications of LiDAR Locations Winona March 27, 28, 29 East Grand Forks April 10, 11, 12, 13 Morris July 25, 26; August 8 Cloquet April 26, 27 Minneapolis, May 15 More sessions are being planned

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