Municipal Projects in Cambridge Using a LiDAR Dataset NEURISA Day 2012

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 – 10th 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 (95th percentile) or better for bare
earth
Within 30cm RMSE (95th 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
1400m
71800hz
Point Spacing
1.0 m
Sidelap
30 %
Scan Full Angle (FOV)
Missions Flown
40 degrees
November 9 & 10 (2009)
8
8
LiDAR Evaluation
Category
Criteria
Point Density (nominal)
1.0 points per meter²
Collection Coverage
100%
Flight Line Calibration – no gaps
Horizontal Accuracy
1.0 meter (RMSE)
Vertical Accuracy (bare earth)
15.0 cm (RMSE)
LAS Classification
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
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Lo
w
Existing TC
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ig
Lo
w
Possible TC
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
[email protected]
www.cambridgema.gov\GIS