2005 Statewide Orthophotography Control

February 20, 2008Indiana GIS Conference

By Ryan C. Swingley, LS

USI ConsultantsThomas A. Mahon, PE, LS

Woolpert Inc

Project Team

• Prime Consultant - EarthData – Photo Firms

• 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’dProposed 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

• 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

• 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

• 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– 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?