Municipal Projects in Cambridge Using a LiDAR Dataset NEURISA Day 2012 Sturbridge, MA October 15, 2012 Jeff Amero, GIS Manager, City of Cambridge
Presentation Overview Background on the LiDAR dataset Solar Tool Project Tree Canopy Project LiDAR software demo by Jarlath
Cambridge by the Numbers 7 square miles (6.4 square miles of land) 105,162 residents (2010 Census) (16,000 persons per square mile 10 th densest city in US) 30,000 university students 13,300 parcels 18,000 buildings 13 neighborhoods Over 20,000 street and park trees
City of Cambridge GIS Department LiDAR Dataset
LiDAR Acquisition Approached by Sanborn to buy into a National Renewable Energy Laboratory (NREL) LiDAR flight in 2009 Purpose of project for Boston Redevelopment Association (BRA) renewable energy and solar project Bought into the flight which was flown in November 2009 Agreed to supply own control points to lower cost Cost to Cambridge - $5,000
LiDAR Data Set Specifications 1.0 meter average spacing Over 125 million data points Processed to classify bare earth and above ground points Vertical accuracy Within 15cm RMSE (95 th percentile) or better for bare earth Within 30cm RMSE (95 th percentile) or less for other land categories No contours or DTM breaklines created as part of project Delivered in LAS format
LEICA ALS50 Airborne GPS/IMU PDOP (<3.2) KP-index (<4) Acquisition Specifications for LiDAR Flight Altitude Repetition Rate Point Spacing 1400m 71800hz 1.0 m Sidelap 30 % Scan Full Angle (FOV) 40 degrees Missions Flown November 9 & 10 (2009) 8 8
LiDAR Evaluation Category Point Density (nominal) Criteria 1.0 points per meter² Collection Coverage 100% Horizontal Accuracy Vertical Accuracy (bare earth) LAS Classification Flight Line Calibration no gaps 1.0 meter (RMSE) 15.0 cm (RMSE) 1=Unclassified; 2=Ground; 7=Noise; 12=Overlap Artifact Removal 95% Outlier Removal 98% Vegetation Removal 97% Building Removal 99% Edgematch Smooth transition between tiles, No Gaps
. LiDAR survey covering City of Boston (& Cambridge) 1.0 meter point density Over 90 sq. mi. (48.4 sq mi Land) 15.0cm Vert. (RMSEz) 30cm (other) Control network established using NGS Points Meets FEMA guidelines for LiDAR-based DEM Ground Checkpoints 10
Project Deliverables LiDAR Data Tiles LAS Format Class 1 (unclassified) Class 2 (ground) Class 7 (noise) Class 12 (Overlap) BE (ESRI) GRID (1m) Documentation & Reporting FGDC-compliant metadata (project) LiDAR Acquisition Report All data geo-referenced to the Massachusetts Mainland State Plane Coordinate System, (NAD83 - US Foot) horizontal Datum, and (NAVD88 US foot) vertical Datum.
Cambridge Community Development Department Solar Tool Project
Solar Tool Background Collaboration between Christoph Reinhart & Alstan Jakubiec from MIT Sustainable Design Lab and City of Cambridge July 2011, first discussions Most of the work done late 2011, Web 2012 Project also presented as a paper to SimBuild in 2012 Web design and architecture by Modern Development Studio (MoDe) Eduardo Berlin For Both Photovoltaic (PV) & Solar Hot Water (SWH) installations
LiDAR in Solar Tool Elevation measurements Uniformally resampled LiDAR data over a 4 x 4 grid using ArcGIS Spatial Analyst 126,624,764 data points Took the mean of the first return data where multiple points existed Resulting neighboring points which did not vary by greater than 1 foot discarded Result = 9,403,740 points without losing much geometric resolution Created 3D model using custom scripts
Other Factors in Solar Tool 5 x 5 grid was created for each building. Building polyline used on edge of buildings for better resolution in 3D model Slope, rooftop mechanicals, & tree canopy were considerations Solar data per hour over one year included in calculations Used averages from Boston weather station data Comparision of energy consumption in model to real data from electric utility
Solar Tool Results Better data than flat roof models Precise hourly simulated irradiation data mimics actual sky radiation throughout the year 3D model more accurate than a pure DEM More accurate placement of solar panels from slope and obstruction information More accurate calculations for installation costs and comparison of energy and dollar savings Future analysis will account for 45 degree roof brackets tilting south on flat roofs
Cambridge Solar Tool Demo LIVE: http://www.cambridgema.gov/solar/ VIDEO: http://mit.edu/sustainabledesignlab/projects/cambridgesolarmap/index.html
Latest review on Fast Company Web Site 10/12/12
Cambridge Community Development Department Urban Tree Canopy Study
Urban Tree Canopy Background Collaboration between: Jarlath O Neil-Dunne of the University of Vermont Spatial Analysis Laboratory UVM Rubenstein School of the Environment and Natural Resources City of Cambridge Discussion began in Fall 2011 Bulk of work done in Spring 2012 Other studies completed by UVM Spatial Analysis Lab prior to Cambridge Goal was to apply the USDA Forest Service s tree canopy assessment protocols to the City
LiDAR in Urban Tree Canopy Study LiDAR and 2010 orthophotos GIS layers to support analysis Used Quick Terrain Modeler and ecognition Digital Elevation Model (DEM) Represents the topographic surface Digital Surface Model (DSM) Represents the true 3D surface of all features relative to sea level Normalized Digital Surface Model (NDSM) Represents the height of features relative to the ground LiDAR intensity layer Strength of signal returned to the sensor
Why Urban Tree Canopy Study?
Analysis on Tree Canopy Assessing Database Land Use Neighborhoods Address Blocks Sidewalks Street Tree Height Demographics Tree Canopy Opportunity Index
Existing TC Low High
Possible TC Low High
Tree Canopy Report Results How much tree canopy in Cambridge? 1,222 acres covered by 30% of all land in City How much more land would support tree canopy in Cambridge? Theoretically, additional 1,447 acres or 35% could be modified
- Data - Report - Presentation
Next Steps for Cambridge Set Urban Forestry Goals Pilot area to determine tree planting potential Analyze sidewalk widths for more street tree planting Work with data sets delivered by UVM for more analysis on tree planting Work with Harvard and MIT on trees Promote tree planting and care with residents and businesses Combine with Harvard study on Urban Heat Island Effect
For more information about Cambridge GIS Jeff Amero - GIS Manager City of Cambridge 617-349-6015 jamero@cambridgema.gov www.cambridgema.gov\gis