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Southern Piedmont and Mountains Orthoimagery 2015
The Southern Piedmont and Mountains Orthoimagery 2015 Project, funded by the
NC 911 Board, has concluded.
The NC Center for Geographic Information and Analysis (CGIA) managed the project as part of a
four-year update cycle for the 2010 statewide orthoimagery. The Southern Piedmont and Mountains
Orthoimagery was Phase 4 of 4 that delivered to 30 Primary Public Safety Answering Points (PSAPs)
and county GIS contacts for 24 counties in January 2016
(Cycle 2 Summary Map).
Phase 1 (25 counties on the coast) was delivered in February 2013. Phase 2 (25 counties in the eastern piedmont)
was delivered in January 2014. Phase 3 (26 counties in the northern piedmont and mountains) was delivered in January 2015. The project
team included the NC Department of Transportation Photogrammetry Unit, the Land Records Management Program
in the Office of the Secretary of State and the NC Geodetic Survey in the NC Department of Public Safety.
Technical advisors included the Working Group for Orthophotography Planning. Private contractors for imagery
acquisition in 2015 were Sanborn Map Company, Atlas Geographic Data, Surdex Corporation, Spatial Data Consultants,
and Quantum Spatial (Project Summary Map).
Similar to the Statewide 2010 Orthoimagery
Project, Phase 1,
Phase 2, and
CGIA delivered true color orthoimagery, 6-inch ground resolution, in uncompressed and compressed formats.
The emphasis was to produce high resolution imagery to support 911 communications and base mapping in local
governments. The imagery is available online through the NC
OneMap Geospatial Portal, through image services and downloadable data, the same as for the statewide
2010, 2012, 2013, and 2014 imagery.
CGIA entered into contracts with photogrammetry service providers in December 2014 and flights were completed for
imagery acquisition on April 11, 2015 ahead of leaf-on conditions in the mountains.
The Project Summary Map displays the final acquisition dates for each of the over 100,000 exposures collected throughout the project
area. Through the spring and summer, raw imagery was post-processed by Aerial Triangulation (AT) Blocks. Contractors delivered
four stages of compliance reporting and approval, including Imagery Acquisition reports, Exploitation Image Post Processing,
Airborne GNSS-IMU Post Processing and AT.
Project Quality Review
A significant portion of this project is the visual quality review phase that begins in August. The 911 Board required
early review by end-users prior to delivery. To accomplish this, the project team developed an Internet imagery viewer
called VOICE (Virtual Online Inspection, Checking & Editing), much like the NC OneMap Data Explorer, to
enable users to identify quality issues and submit comments. VOICE has been utilized for all phases of the project
and has proven to be a very efficient means for multiple end-users to evaluate their county concurrently.
In July of 2015, the project team conducted two web-based training sessions on the use of the VOICE imagery review tool,
including a live demonstration of tools available in VOICE, a walk-through of the QC workflow, and a discussion of
expectations, guidelines, and requirements for review. Recordings of the web-based training sessions have been made
available online for those who were unable to attend.
The training has been divided into five parts:
Detailed End-User HELP
as well as
End-User QC HELP
(specific examples of the types of QC reporting issues) can be found through the online system.
The QC delivery schedule was defined by the release of four counties per week.
The schedule spanned over four months from August through December. The project team evaluated issues reported
through VOICE and submitted problem images to the acquisition vendors for resolution. Through November, all issues
were resolved and VOICE was refreshed in mid-December to represent final delivery.
At final delivery, the Project Team provided a report that summarizes all VOICE documented issues. This documentation
can also be found interactively through the Project Summary Map.
All of the CALLS, or issues submitted to contractors for resolution, can be found through discovery by clicking
on red outlines of locations that display thumbnails of how the imagery looked prior to having the issues resolved.
This can be compared with the final imagery in the base layer on this map to allow the user to visualize
how the quality of imagery improved through the review process.
In addition, the project team managed a process for horizontal quality control that checked the precise
positional accuracy of the imagery for base mapping purposes. The process compared surveyed points on the
ground to the same points visible in the imagery and computed statistics to evaluate the precision of the
imagery. This assured that distances were accurately represented in the imagery.
In late December, the project entered into the distribution phase where CGIA worked with 911 PSAP contacts to establish
regional distribution meeting locations at five locations in the southern piedmont and mountains project area.
The presentation from these meetings can be found here. The regional distribution meeting locations were held in:
- Asheville - January 19, 2016
- Buncombe County Emergency Communications, Haywood County 911, Henderson County Sheriff Communications, Transylvania County 911 Center
- Franklin - January 20, 2016
- Cherokee County, Clay County Dispatch, Eastern Band of Cherokee Indians, Graham County 911, Jackson County Emergency Management,
Macon County Communications, Swain County 911
- Shelby - January 21, 2016
- Cleveland County 911, Kings Mountain Communications, Gaston County 911 Communications, Lincoln County Communications Center, Mount Holly Police Department,
Polk County Communications, Rutherford County Communications, Shelby Police Communcations
- Carthage - January 27, 2016
- Montgomery County 911 Communications, Moore County Emergency Services, Richmond County Emergency Center, Scotland County Emergency Communications
- Concord - January 28, 2016
- Anson County Emergency Communications, Cabarrus County Sheriff Communications, Charlotte-Mecklenburg Police Communications,
Cornelius-Huntersville Police Communications, Pineville Police Department, Stanly County 911, Union County Communications/E911
At the delivery meetings, each Primary PSAP was provided a hard drive that included uncompressed imagery tiles in TIFF file format,
as well as 20:1 compressed MrSID tiles that cover the entire primary county and extend to a minimum of seven miles outside the county boundary.
Along with these tiled products, a single-file 50:1 compressed MrSID mosaic file was delivered that also extends to a minimum of seven miles
outside the county boundary. In addition, each delivery included the single-file MrSID mosaic file for each adjacent neighbouring county
to provide a complete regional coverage.
Following delivery, the project entered into a 60-Day period where the end-user evaluates the imagery deliverable to insure customer
satisfaction, confirm completeness, validate data integrity, and to improve the process for the project and subsequent phases.
The 60-Day period ended April 4th and no issues were reported.
NC OneMap Update
Concurrently with the 60-Day term, access to the imagery was loaded and can now be found through the
NC OneMap Geospatial
Portal. Just like 2010, 2012, 2013, and 2014, the 2015 imagery is available as web services in ArcGIS
Image and WMS formats. Users have instantaneous access (similar to Google Maps) to all of the imagery
(1995-2015). Users of ArcMap, Microstation, AutoCad, ArcGIS Online, and others can all take advantage of
these services. The NC OneMap Geospatial Portal features many customizations including the ability
to preview and download imagery from multiple calendar years, get instant map and image service status,
browse collections from A to Z, and more.
- Tim Johnson
- Director, Center for Geographic Information and Analysis
- Phone: 919.754.6588
- Darrin Smith
- Project Manager, Center for Geographic Information and Analysis
- Phone: 919.754.6589
- Ben Shelton
- GIS Analyst, Center for Geographic Information and Analysis
- Phone: 919.754.6377
Feb '16 - 2015 Imagery Online The 2015 orthoimagery is now available from the NC OneMap GeoSpatial Portal. Read on for all of the details. read more ... July '15 - NC Parcels Contains All Counties
North Carolina now has a parcel data set that includes all 100 counties and areas comprising the Eastern Band of the Cherokee Indians. read more ...
Feb '15 - New counties added to NC Parcels
36 counties have recently been added to NC Parcels. read more ...
Feb '15 - 2014 Imagery Online
The 2014 orthoimagery is now available from the NC OneMap GeoSpatial Portal. Read on for all of the details. read more ...
Dec '14 - Statewide Addresses now available
2014 address points are now available for download and as a web service from the GeoSpatial Portal. read more ...
Aug '14 - Larger areas of imagery available for download
We have doubled the amount of imagery that is available in a single download. read more ...
Feb '14 - 2013 Imagery Online
The imagery for 25 counties in the Eastern Piedmont region is now available as a region-wide image service and for download in areas of interest. Visit the NC OneMap Geospatial Portal or watch the video
to see a demo of how to access the new imagery. read more ...
Nov '13 - Elevation Data now available
Elevation data are now from NC OneMap as a web service and a download. read more ...