North Carolina Digital Orthoimagery 2022 Study Area #: Watagua, Ashe, Wilkes, Surry, Alleghany, and Yadkin Counties.

Orthoimagery in North Carolina captured during leaf-off conditions in early 2022, 6-inch ground resolution, is a public resource provided by North Carolina's Statewide Orthoimagery Program, supported by the NC 911 Board. The state program includes orthoimagery acquired between 2012 and 2022. The Program is consistent with the Business Plan for Orthoimagery in North Carolina (https://it.nc.gov/documents/files/business-plan-orthoimagery-north-carolina/download?attachment) that recommends acquisition of one-fourth of the state (or 25 counties) per year in a four-year cycle. The products for 2022 are orthoimagery in 4-band true color with IR (RGBIR) (2012-2019 was 3-band, RGB), 6-inch ground resolution in 5,000 by 5,000-foot tiles, in uncompressed and compressed formats, packaged by county for distribution and accessible through the NC OneMap Geospatial Portal. The project was managed by the NC Center for Geographic Information and Analysis (CGIA) in the NC OneMap framework of data access. CGIA collaborated with the NC Geodetic Survey, the NC Department of Transportation's Photogrammetry Unit, and the Land Records Management office in the Office of the Secretary of State to form a state team with expertise and experience in orthoimagery. Acquisition contractors were selected by a Qualifications-Based Selection process. In addition the Statewide Mapping Advisory Committee's Working Group for Orthophotography Planning provided technical advice. Images were collected with digital cameras in early 2022, image processing and quality control occurred through 2022, and products became available by late 2022. Image services are accessible and data are downloadable through NC OneMap. This 26 county orthophoto project is referenced herein as Northern Piedmont and Mountains 2022 (NPM22) Study Area SA2. Imagery was acquired with Two Cessna 441 Conquest aircraft with airborne acquisition systems using Leica ADS100 sensors, GPS-IMU sensors with Leica Tools for flight planning and camera control and image acquisition management. Imagery was acquired between February 11 and March 21, 2022 by a total of 16 sorties. Digital airborne imagery was acquired during deciduous leaf off, cloud free, minimum 33 degree sun angle conditions. The beginning and end date of imagery acquisition was incorporated in the final orthoimage tile naming scheme as the last two fields in the tile name, incorporating the revision number in the last field; the beginning date of acquisition designated as: 02/11/22 and the final date of acquisition designated as: 03/11/22(e.g. OF6i0_37_000_20055902_########_####R0.tif). The raw imagery was post processed using a very strict and consistent process to ensure radiometric consistency throughout the project. Aero-Triangulation (AT) was conducted to consolidate the individual images and flight lines into mathematically cohesive blocks that are geo-referenced to the designated project coordinate system and datum to support orthoimage production. One AT Block was involved with NPM22 SA# imagery covering all referenced seven counties. Ground control was provided from paneled NCGS monuments and new pre-paneled locations that were surveyed by GPS with OPUS and RTN procedures. Digital Terrain Model (DEM) data for differential orthophoto rectification was provided by NC Floodplain Mapping LiDAR (Bare Earth and grid TINS postings) which was reviewed and updated as necessary at a density level sufficient to accurately represent the shape of the ground and to meet the required ASPRS Class I Orthophoto accuracy standards for 1 inch equals 100 foot scale mapping. Seamline polygons were generated by a combined auto-correlation process and manual digitizing with edits as necessary for each individual orthorectified image to produce a seamless mosaic of ortho-rectified imagery. Seamlines were delivered as ArcGIS attributed polygons for all 6 counties of NPM22 SA2 with each polygon having attributes of flight line number, exposure number, image acquisition date, and ESRI generated parameters of area and perimeter distance. Seamline data for the Six counties within NPM22 SA2 has also been documented and described as a separate metadata file. This separate and independent NPM22 SA2 seamline metadata file can be obtained from CGIA. Project status was reported to the client (CGIA) on a weekly to biweekly basis by submitting a written status report with supporting documentation. Project status meeting conference calls were held every week or every other week to review status and discuss action items. All project tasks and sub-tasks were detailed, documented and reported to CGIA in detailed Attachment Reports: C (Flight and Control Plan), C-1 (Ground Control Surveys), D (Imagery Acquisition Compliance), E (GPS-IMU Post Processing and Aero-Triangulation), F (Orthoimagery Delivery per county), and G (Final Report). The NPM22 project was divided into five Study Areas (SA) with the SA2 counties described herein as: Watagua, Ashe, Wilkes, Surry, Alleghany, and Yadkin Counties comprising Study Area 2; thereby designated as NPM22 SA2.