2005 Statewide
Orthophotography Control
February 20, 2008
Indiana GIS Conference
By
Ryan C. Swingley, LS
USI Consultants
Thomas A. Mahon, PE, LS
Woolpert Inc
Project Team
• Prime Consultant - EarthData
– Photo Firms
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Earth Data
Woolpert
Horizons
Northwest Geomatics
– Survey Firms
• Woolpert
• USI Consultants
• Accu-Air
Project Overview
• Imagery intended to assist agencies at all
levels of government
• To be used to assist with homeland security,
economic development, tax assessment,
highway planning, environmental
monitoring, and crime statistics, to name a
few more
• Seven aircraft to collect 50,000 images over
two months flying seven days per week
• State funded 12” pixel imagery
• Counties could “buy-up” to 6” imagery
Project Overview
• Flying Started February 18, 2005
• Flying Initially Ended April 15, 2005
(two weeks ahead of schedule)
• Initial Re-flights Ended May 28, 2005
• Ground Control Started 03/24/05
• Ground Control Ended 05/02/05
• Final Ground Control Coordinates
delivered 05/31/05 (one week early)
Project Overview Cont’d
Proposed Blocks
Technology
• Leica ADS40 made project
possible because
– It can be flown higher
– It can be flown faster
– It requires less ground control
(IMU)
– It uses multiple sensors allowing
data capture in a single pass
– It is all digital
Impact of Schedule
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Original contract expected 12/31/04
Contract delayed approx. 2 mos.
Delay reduced planning time
Waiting for targets would have
delayed flights
• Schedule could not slip
• Targets were out, photo ID was in
• What is meant by Photo ID?
Normal Photo Control
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Flight plan
Target locations
Tolerances
Place targets and control
Leave targets in place until film
QC’ed
• Pick up targets
• Or use photo ID
Normal Photo Control
Statewide Photo Control
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Flight plan – Provided by ED
Tolerances – Provided by ED
No targets, “photo ID”
6” Pixel control may move up to
500’ from intended location
• 12” pixel control may move up to
2,000’ from intended location
Proposed Control
Performance Specifications
• Horizontal and Vertical
Requirements for Control
– Photo-identifiable points must be
clearly visible from the air
– Points must have sufficient
definition
– Examples
• Right-angle intersections of sidewalks
• Intersections of b-ball court stripes
• Corners of stop-bars and chevrons
Performance Specs Cont’d
• 6” Pixel Photo-ID Points
– Horizontal Accuracy: 0.5’
– Vertical Accuracy: 0.15’
– Maximum Shift: 500’
• 12” Pixel Photo-ID Points
– Horizontal Accuracy: 1.0’
– Vertical Accuracy: 0.3’
– Maximum Shift: 2,000’
Observation Criteria
• Two baselines per point
• Minimum observation time is equal
to distance to second furthest base
station, measured in km, plus five,
expressed in minutes (i.e., 25 km to
second furthest base station requires
minimum of 30 minute observation
time) when a minimum of six
satellites are available (PDOP < 4.0)
Field Procedures
• Field Equipment
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Trimble 4000
Trimble 5700
Trimble 5800
All L1 / L2 Receivers
Field Procedures
• Navigation
– Recreational GPS hand held
– DeLorme Street Atlas
Field Procedures
• Communications and Planning
– Morning and Evening Discussions
– ID and Control Assignments by the
Field Manager
– Cell phone through out the day
Field Procedures
• Field Notes
Field Procedures
• Field Notes
Field Procedures
• GPS Data, Photos and
Transcribed Field Notes were
downloaded and post to FTP site
nightly
Challenging Targets
• Target #125 on Ky Side of Evansville
Challenging Targets
• Drift Wood Target #125
Challenging Targets
• Target 101 Near Confluence of the
Wabash and Ohio
Challenging Targets
• Target 101 Near Confluence of the
Wabash and Ohio
Good Targets
• Stop Bars
Good Targets
• Edges of Concrete
Good Targets
• Good Considering the Area
Good Targets
• Sometimes we got lucky
Withstanding the Scrutiny of
QC
• All GPS Network Adjustments
were within tolerance
• All AT Solutions were good
• Blind QC Points were good
• Rensselaer checks good
Final Control Deliverable
• UTM Zone 16/NAD83(97) in
meters &
• State Plane Coordinates, east or
west zone, US Survey Feet
• 11th Hour Switch to NAD83(86)
• NAD83(97) to NAD83(86) shift:
– N = 4”, E = 9”, Hz = 10”
• NAVD88 to NGVD shift:  4.7”
Final Control Deliverables
Horror Stories
• Huntingburg Airport and
airborne support
– The only Trimble 4000 SSE that
logged data at 0.2 Hz
– Flying in Kosciusko County,
Controlling in Dubois County
• Ryan’s first day
Success Stories
• IUCO
• IndySV
• Google Earth
Success Stories
• Google Earth
2005 Ortho Control
• Questions?
• Comments?