Washtenaw County 2008 LiDAR Project Overview Nate Arnold, GIS Developer Washtenaw County Support Services

What is LiDAR Light Detection and Ranging (LiDAR) is a remote sensing system used to collect high-resolution elevation data. A LiDAR sensor is mounted on-board an aircraft. During the flight, the LiDAR sensor pulses a narrow, high frequency laser beam toward the earth. The LiDAR sensor records the time difference between the emission of a laser beam and the return of the reflected laser signal to the aircraft. The data is provided as a set of elevation points, an intensity image and an image classified into land cover categories

Washtenaw County Project Collect LiDAR data Fall Sq Mile County plus ½ mile buffer around all sides 1 meter point spacing / 30 % side lap Classified by land cover type (building, vegetation, bare earth, water, etc.) Create 2’ Contours Hydro enforced Create Building Footprints Buildings 10’x 10’ or greater Attributed with building height

Project Partners The 2008 LiDAR collection is a cooperative project between the: US Geological Survey (USGS) National Resource Conservation Services (NRCS) Wayne County Monroe County City of Ann Arbor Washtenaw County

Applications of LiDAR Data Flood inundation studies Disaster recovery analysis Line of sight analysis Vegetation studies (street tree mapping, agricultural land studies, etc.) Drainage and runoff analysis Floodplain delineation Change detection for assessment purposes Transportation analysis Improved orthophoto accuracy (LiDAR surface used in photo correction) Some examples of these applications are outlined below:

The Raw LiDAR Data will be classified by land use category to provide a clear picture of the County’s Urban, Suburban, and Rural landscape. Blue = Buildings Green = Vegetation Red = Bare Earth White = Impervious Surface

Flood Inundation Studies With LiDAR elevation data, EMD personnel can study the effects of heavy rainfall by calculating “what if” scenarios. In this example, the analyst looked at what would happen to Ohio Stadium if the Olentangy river rose 10 feet.

Data can be examined as a cross section for runoff calculations and flood recovery analysis

First responders can utilize the LiDAR information to visualize the effects of flood events on emergency response and evacuation routes

In addition, emergency personnel can visualize water depth across the affected area.

LiDAR data can also be used to model the effect of dam or levee breaks.

Using LiDAR data and building footprints, EMD staff in Volusia County, Florida were able to examine the effect of a tornado strike and calculate the amount of debris removal needed. Event Recovery

Tornado Path Path digitized from post-event aerial imagery

Pre-Event LiDAR data

Post-Event analysis

Tornado path extrapolated on LiDAR base data Volume of debris calculated from LiDAR data analysis was used to estimate remedial costs (trucks, equipment, etc.)

Users can create 3 dimensional fly-throughs to better visualize project sites for a variety of applications 3-D Visualization

Detailed building extrusions can be created to show building facets and enhance analysis and visualization 3-D Visualization

Line of Sight Analysis Viewshed from ground levelViewshed from elevated level - Event Planning- Civic Planning - Tactical Operations- Security Cameras

Line of Sight Analysis in Cleveland, Ohio Area visible from Key Bank Building in Cleveland (Blue)

Area visible from cheap seats at Brown Stadium (Yellow)

Area visible from Brown Stadium and Key Bank (Pink)

Washtenaw County Examples 800 MHz tower locations Determine highest elevation on given site parcel Determine necessary height to overcome obstacles and select sites based on line of sight Outdoor warning sirens Incorporate viewshed analysis Possible to create “sound contours” to model dB at given location ALOHA/CAMEO Contaminant vapors may follow topography Plume models may be combined with LiDAR-generated surface

Project Budget Product Amount BudgetedActualVariance Lidar Project$250,000$500,000*($250,000) *1m Raw LiDAR Data, Bldg footprints, and 2’ contours Total Variance($250,000) Project Partners: Savings From Regional Effort $ 14,500 City of Ann Arbor Contribution $ 30,000 Variance w/Partners($205,500)

Project Area LiDAR collection will include the entirety of Washtenaw, Wayne and Monroe Counties Monroe County: $100,000 (funded through UASI) Wayne County: $50,870 Washtenaw County: $145,500* 3 meter data will be public domain and available through the USGS. 1 meter data will be owned by the individual counties. Each participating county will have access to the data for the entire project area. * Cost for LiDAR collection only. Cost for building footprints and contours are included in the overall project budget outline below.

Project Timeline September - October 2008 – Funding agreement signed with USGS and project partners November 2008 – Data collection begins January 2009 – 1/3 of project cost due March 2009 –Delivery of Raw LiDAR data to project partners, 1/3 of project cost due June 2009 – Contour and Building Footprint delivery to partners, Remaining 1/3 of project costs due

Questions Contact: Nate Arnold, GIS Developer Washtenaw County Support Services