CIR Imagery: Issues and Applications

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CIR Imagery Issues and Applications
March 1-2, 2007 North Carolina GIS Conference
Presented by Jim Cannistra, CP, Sanborn
jcannistra_at_sanborn.com [phone]
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Topics

• Color Infrared Imagery Overview
• Impacts of Digital Camera
• Technical Issues
• Production Methods
• Timing (leaf on or leaf off)
• Color Balancing
• File formats
• Applications
• North Carolina Projects

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Color Infrared

• Captured with Film or Digital Cameras
• Also known as false color
• CIR film initially developed in 1960s
• Camouflage detection
• CIR additionally captures NIR wavelengths of
  electromagnetic spectrum
• 0.4 - .7 visible
• 0.7 1.0 NIR
• Longer wavelengths
• Thermal IR used for heat detection
• BW IR used for coastal studies

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Color Infrared Programs

• Historically CIR film used for environmental
  studies
• Often non-photogrammetric
• Some State / Federal CIR Programs
• New Jersey and Delaware
• NAIP (Tennessee and South Carolina)
• USGS (North Carolina)
• Satellite Imagery
• - Multispectral

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Digital Cameras

• Large Format Sensors
• Leica Geosystems ADS40
• ZI/Imaging DMC
• Vexcel UltraCAM
• Beginning to be used extensively for Statewide
  and NAIP programs
• Used for an increasing number of local government
  projects

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Benefits of Digital Camera

• More Information Multi-Spectral
• Data acquisition expanded
• Imagery review
• Superior Image Quality
• Noise artifacts
• Shadow detail
• Greater Redundancy of Imagery
• More Information 12 bit
• Potential cost / schedule

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Orthophoto Production Process

• Data acquisition
• Processing of imagery
• Multispectral file
• Color CIR bands
• DTM Collection
• Seamline generation
• Orthorectification
• Color balancing
• Multispectral
• Color band CIR band
• QC Image fixes

Decisions about CIR products should be made up
front to minimize duplication of production
processes
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Deliverable Formats

• Separate set of Imagery
• Duplicate set of images
• 4 band file
• JPEG 2000
• Each file 25 larger
• Overall data storage is less

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Color Balancing

• Color balancing
• Yes / No
• Color balancing may degrade spectral information
  that can be obtained
• Depending of processing CIR color balancing done
  separate from RGB color balancing

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Leaf On versus Leaf Off

• Leaf on
• Summer photography
• NAIP program
• Vegetation Analysis
• Leaf off
• Fall / Spring
• Typically done for base mapping
• Support compilation (DTM/Plan features)
• Wetlands mapping
• Impervious surface apps

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Morris County, NJ0.5 resolution analog camera
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Pueblo, Colorado 1 resolutionDigital Camera
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Pueblo, Colorado 1 resolution
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New Hanover County, NC0.5 resolution digital
camera
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Horry County, SC0.5 digital camera
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Cincinnati CAGIS0.5 resolution digital
camera
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Suriname, South America
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CIR Imagery - Applications

• Traditionally most useful for natural resource
  apps
• NIR wavelengths reflected most by health
  vegetation
• Different types of vegetation reflect different
  amounts of NIR imagery
• Allows vegetation differentiation
• Impervious Surface
• Water and asphalt absorb almost all IR light
• Most features appear on imagery as black or grey

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ApplicationsWhat Projects can CIR Imagery
Support Miles B. DavisGIS Coordinator NC
State Farm Service Agency

• Impervious surface analysis
• Vegetative vigor
• Utility Easement encroachment from vegetation
• Water purity (particulate density)
• Cell tower line of site visualization
• Wetlands delineation / restoration planning
• Airport end of runway/glidepath line of sight
• Invasive weed monitoring
• Urban tree canopy inventory

• Forest inventory
• Submerged aquatic vegetation inventory
• Potential wildfire risk area assessment
• Landcover identification and analysis
• Habitat analysis
• Green-space analysis and planning
• Land/Water separation
• Change detection / habitat loss over time
• Soil moisture location

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Impervious mapping

• Impervious mapping can be used for
• Measurement of development
• Estimation of stormwater runoff potential
• Modeling of stormwater
• Assessment of stormwater use fees
• Watershed health assessment
• Assessment of human impact on local environment
• Features
• Quick
• Repeatable
• Measures all areas within project
• Produces coverage that can be summarized by land
  parcels
• Accuracies 90 95

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Automated Impervious for the City of Ann Arbor
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Water Quality / Sedimentation
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Casper Mountain Example

• Multispectral imagery
• 1 ft resolution
• 4 bands
• Blue
• Green
• Red
• Near Infrared
• 12 bits (1 - 4048)
• LiDAR
• 1.4 m post spacing
• First return
• Last return

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Species Identification
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Mapping Approach

• Labeling editing tool for manual interpretation
• Field visits and local expert knowledge was
  needed to get map to desired accuracy

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Counting trees

• Sanborn conducted a study to determine the
  utility of segmentation to discriminate
  individual citrus trees to determine where trees
  were missing

Individual tree segmentation (Blue polygons)
Image filtered to reduce heterogeneity in
individual trees
1-meter image
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Fuels Mapping

• For regional assessments, fuels are typically
  mapped at 30m resolution using Landsat imagery
• For community assessments, fuels can be mapped at
  5m or less
• Advanced image classification techniques are used
  in combination with field surveys to develop a
  fuel model classification scheme
• Supports the 13 FBPS fuel models, or the newly
  developed Scott/Burgen 40 fuel models

CIR Imagery
Surface Fuels
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Cost Factors

• Processing of Imagery
• Increased file handling
• Effects compilation
• Effects orthorectification
• Color Balancing
• Some orthorectication tools require separate
  process
• Additional Deliverables
• Added Value

10-20 K per County 10 cost impact
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CIR Projects in North Carolina

• DOQQs
• 1998/1990
• Sanborn
• Camp Lejeune MCB
• Cherry Point MCB
• US Fish and Wildlife
• Dare Hyde County
• New Hanover County
• Out Lying Landing Field (OLF) Washington Co

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Questions Discussion

• Summary
• CIR Supports many applications
• Consider for any digital camera project
• Leaf on versus leaf off dependent on applications
• Decide up front