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Supporting an Accessible Geodetic Control Network for California
Presented by:The California GIS Council's Geodetic Control Work Group
(CGWG)
A Growing Concern for the Geospatial, Land Surveying and Mapping Communities
Presentation Topics
1) Introduction of the GCWG.
2) Importance of a common reference frame.
3) Why GIS data needs Geodetic Control.
4) Geodetic control resources in California.
5) What's Next?
Geodetic Control Work GroupFormation History and
Information
The California GIS Council authorized formation of the Geodetic Control Work Group in November 2009. The work group was assembled in March 2010 & chaired by Marti Ikehara, retired NGS Advisor to California. A charter and work plan were approved by the CA GIS Council in April, 2011. Bi-monthly or Monthly teleconferences and meetings. Outreach subcommittee to give presentations. The CA GCWG operates independently of other groups.
CA Geodetic Control Work Group
GCWC – who are we?Chartered by CA GIS Council in April, 2011
GCWG Sub-committees oStrategic Plan SubgroupoData Standards SubgroupoOutreach / Communication Plan
Current Chair, Scott Martin – Caltrans
John Canas - CSRC Landon Blake – O’Dell Engineering, Inc.
Tom Dougherty - S.C.V.W.D Justin Height - Penfield & Smith, ACEC, CA
Ryan Hunsicker – Sn.Bdo.Cnty, CLSA
Bruce Joffe - GIS Consultants
Ric Moore – BPELSG Neil King – PhotoScience, Inc. ACEC-CA
Mark Turner- Caltrans Michael McGee - McGee Surveying, CLSA
Kristin N. Hart - Padre Associates, Inc.
Reg Parks - Santa Rosa Junior College, PVTS
GCWG Milestones for Success
Charter documents (√), Strategic Plan, Work Plan (√), approved by CA GIS Council.
Outreach Plan to elicit feedback
Geodetic control data sources & standards for metadata.
Recommendations for standards, stewardship, and funding for geodetic theme and infrastructure.
Strategic Plan and Business Plan for adoption by the CGC.
Policy and technical statements for utilization and alignment of the GC theme by other GIS themes.
Presentation Topics
1) Introduction of the GCWG.
2) Importance of a common reference frame.
3) Why GIS data needs Geodetic Control.
4) Geodetic control resources in California.
5) What's Next?
(Reprioritized to #1 in 2014 FGDC SDI
7 Federal GIS Framework Layers
Governmental Boundaries
Hydrography
Geodetic Control
Transportation
Cadastral
Elevation
Ortho Imagery
GIS Stacks Map LayersNumerous GIS layers are employed in:
• land development• construction• asset mgmt.,• land analyses• map display• etc.
They are updated frequently.
By whom and on what coordinate system?
Map Layer Alignment – How to….Is that
1928845.23, 6354191.85?
Where’s the pinche control
layer?
No, wait, that’s
1928835.23, 6354192.85
How Do We Align Layers of a Data Sandwich?(or – Is Your Control Wimpy?)
w/ the Geospatial Toothpick Equivalent!Geospatial Data Referenced to Geodetic Control
Objective: Make Everything Line Up
Geodetic Control is (or should be) the foundation for all geospatial products
Without Geodetic Control as a basemap layer, GIS themes may not ALIGN well
Sour
ce: Z
uric
h-A
mer
ican
Ins
uran
ce G
roup
Uniform Layer Registrationvia a Common, Coordinate-Based Control Network
Layer Hydrography
MapUse
Surface water features suchas lakes, ponds, streams, etc.
DataSource
Layer Cadastral
MapUse
Define structure of thesubdivision and ownership ofland
DataSourceLayer Elevation
MapUse
Provides 3rd dimensionalinformation to GIS data
DataSource Layer Ortho Imagery
MapUse
Map Background
DataSource
Layer Governmental Units
MapUse
Governmental Boundaries,zones, districts, etc.
DataSource
Layer Geodetic Control
MapUse
Provides a common referencefor all geospatial data
DataSourceLayer Transportation
MapUse
Model the location,connection, andcharacteristics of roads
DataSource
x1a,y1a,z1a
x2a,y2a,z2a
x3a,y3a,z3a
x1b,y1b,z1b
x2b,y2b,z2b
x3b,y3b,z3b
Every layer is expressed in the same coordinate system as the CONTROL LAYER.
Sam
e D
atu
m &
Co
ord
inat
e S
yste
m
Common Reference FrameImplications are clear
(Its about data and data availability)
Importance of a common reference frame. Surveys – CCS, PRC (Horiz. & Vert.), FEMA &
Elevations Civil Engineering Residential, Municipal, Statewide Construction, Transportation, Hydrography, Hydrology Public Safety First responders, Fire and Rescue, Seismic Early
Warning GIS Projects -- multiple source layer control Future / Science FACTion / 3D / 4D aerial guidance, vehicle guidance, augmented reality
Presentation Topics
1) Introduction of the GCWG.
2) Importance of a common reference frame.
3) Why GIS data needs Geodetic Control.
4) Geodetic control resources in California.
5) What's Next?
GIS Data IntegrationFactious scenario
State mandated County GIS data submission
Parcel Data maintained by County Surveyor
All Counties use the same coordinate system
GIS Data IntegrationFactious scenario
County “A”
GIS Data IntegrationFactious scenario
County “B”
GIS Data IntegrationFactious scenario
County “C”
GIS Data IntegrationFactious scenario
County “D”
GIS Data IntegrationFactious scenario
County “A”
GIS Data IntegrationFactious scenario
County “A”
County “B”
GIS Data IntegrationFactious scenario
County “A”
County “B”
County “C”
GIS Data IntegrationFactious scenario
County “A”
County “B”
County “C”
County “D”
GIS Data IntegrationGoogle’s Solution
Presentation Topics
1) Introduction of the GCWG.
2) Importance of a common reference frame.
3) Why GIS data needs Geodetic Control.
4) Geodetic control resources in California.
5) What's Next?
Geodetic ControlCalifornia Spatial Reference Network
(CSRN)
Passive Monuments: Monuments set in the ground that
require periodic re-observation to determine accurate relative position.
Position only valid at the time of survey.
Active Monuments (CGPS) CGPS station collects data 24 hours a
day and its relative position is continually monitored.
Positions that have become degraded due to earthquakes, subsidence and crustal motion can be updated.
Presentation Topics
1) Introduction of the GCWG.
2) Importance of a common reference frame.
3) Why GIS data needs Geodetic Control.
4) Geodetic control resources in California.
5) What's Next?
Summary of Situation Modern societies need GIS/geospatial data to analyze and
manage a wide variety of resources. Geospatial data comes from different sources, but should
have one thing in common: the frame of reference. Frame of reference must be defined by an accessible and
maintained geodetic control network. Passive networks have limited value: difficult access,
expensive to maintain, vulnerable to movement. Active networks (CGPS) are the future, and are the only
viable and meaningful basis for geodetic infrastructure in California.
California’s active geodetic network is in danger because funding sources are uncertain lack of understanding of importance no definitively appointed permanent steward (i.e.
agency or organization with reliable annual funding)
Role of GCWG GCWG appointed by California GIS Council to
study and advise on geodetic control data standards and infrastructure.
Assessment of situation warrants immediate action: outreach and information gathering.
We will recommend solutions per our charter…...as soon as we figure out what to recommend.
Meanwhile, we need your help with ideas and spreading the word.
Ideas and Possible Solutions Education/Information Presentations, articles, and letters Educate surveyors & GISP’s on importance of geodetic control Be visible and accessible at survey/GIS conferences &
meetings Talk and exchange ideas – someone may already know Research what other states have done – don’t reinvent wheelLegislation All official California GIS data to be tied to the geodetic control Create new agency? Fund existing agency? Advocacy Form technical and financial partnerships/consortiums Seek funding sources Lobbying and promoting
Supporting an Accessible Geodetic Control Network for California
Presented by:
The California GIS Council's Geodetic Control Work Group
(CGWG)Contact:
A Growing Concern for the Geospatial, Land Surveying and Mapping Communities
Thank you for your attention,
participation and feedback!
Ryan Hunsicker Scott Martin
