2022 Pennsylvania NAIP Digital Ortho Photo Imagery

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Digital Georectified Image. | Source Geospatial Form: remote-sensing image | Type of Source Media: UnKnown

The imagery was collected using the following digital sensors: Leica ADS-100 (Serial Number 10530) ,Leica ADS-100 (Serial Number 10510),Leica ADS-100 (Serial Number 10515) ,Leica ADS-100 (Serial Number 10522),Leica ADS-100 (Serial Number 10552) with Flight and Sensor Control Management System (FCMS) firmware:v4.57, Cameras are calibrated radiometrically and Geometrically by the manufacturer and are all certified by the USGS. Collection was performed using a combination of the following twin-engine aircraft with turbines flying at 27,100 ft above mean terrain. Plane types:C441, C414Tail numbers:N441EH,N414EH,N440EH,N441FS,N2NQ,With these flying heights, there is a 27% sidelap, giving the collected data nominal ground sampling distance of 0.60 meters. Based-upon the CCD Array configuration present in the ADS digital sensor, imagery for each flight line is 20,000-pixels in width. Red, Green, Blue, Near-Infrared and Panchromatic image bands were collected. The ADS 100 has the following band specifications:Red 619-651, Green 525-585,Blue 435-495,Near Infrared 808-882,all values are in nanometers. Flight planning was performed in Leica MissionPro over a buffered boundary covering DOQQ extents provided by the USDA.A 500m reduced resolution DEM file was used to determine ground heights. A targeted flight altitude of approximately27,000 feet above ground level for native 60cm image acquisition with sidelap of 27% was used for flight planning parameters. Four Cessna Conquests were utilized for acquisition, the seamline shapefile clarifies which aircraft were used for a given area. All aircraft were equipped with LeicaADS100 systems where utilized for data capture. The Leica ADS100 pushbroom sensor has been calibrated by the manufacturer as well as validated against a local calibration range. The calibration includes measuring the radiometric and geometric properties of the camera. These data are used in the Post Processing Software to eliminate the radiometric and geometric distortion. All aerial imagery was collected with associated GPS/IMU data. ADS collection requires high quality IMU data for processing and was critical for early access hosting of digital data to the web for USDA interim access and review. After early access web delivery was complete, all imagery was triangulated using Leica XPro in which the airborne GPS data was constrained to expected limits. To validate the accuracy of the block adjustment derived from GPS/IMU, sensor parameters and conjugate point measurements, photo identifiable ground control points were field surveyed within each State. These points were surveyed using GPS techniques to produce coordinates that are accurate to +/- 0.25 meters RMSE in XYZ.

The GPS surveying techniques utilized assured that the coordinates are derived in the required project datum and relative to an approved National Reference System. If the block does not fit the control points within specifications the pass and tie points were reviewed for blunders and weak areas. If, after these corrections were made, the block still does not fit the control well the GPS and IMU processing were reviewed. Once the block has proper statistics and fits the control to specifications, the final bundle adjustment was made. As AT points are frequently on man-made and other vertical features not included in the DEM, these orthopoints can only be used to indicate regions of error by the clusters of points that predict excessive horizontal displacement. The final adjustments assure a high quality relative adjustment and a high quality absolute adjustment limited to the airborne GPS data accuracy. This process assures the final absolute accuracy of all geopositioned imagery. Both signalized and photo identified ground control were used to QC and control the IMU/GPS based aerial triangulation bundleblock solution. Surdex Grouping Tool provides real-time updates of the USDA APFO Image Metrics. The image technician adjusts image correction parameters to bring the radiometric characteristics of large groups of images within the Image Metrics ranges. For each project area the highest resolution DEM or LiDAR was obtained and utilized for rectification of captured imagery. A visual inspection of the final DEM using color cycled classification by elevation and a shaded relief was performed to check for gaps, corruption and gross errors. The predicted horizontal error for each point was added as an attribute in the SURDEX enterprise database. An operator reviews ortho seamline areas these predicted errors indicate horizontal error in excess of the contract specifications. Any imagery errors introduced by source DEM required patching from an alternate perspective or strip of photography.

Processing hardware used included various brands of survey grade GPS receivers, various brands and models of computers,RAID6 storage, calibrated monitors, various brands of monitor calibration colorimeters. Leica XPro was used for post processing of ADS pushbroom data, triangulation and orthorectification. SURDEX software was used to color correct and remove bidirectional reflectance, vignetting and other illumination trends. USDA APFO Image Metrics are measured and images corrected to conform to the Image Metrics using SURDEX software. GPS/IMU data was reduced to projected coordinates in the appropriate UTM zone using Inertial Explorer software from Novatel. Aerial Triangulation and orthorectification was performed using Leica XPro. SURDEX software was used to adjust for minor radiometric variation between adjacent images. SURDEX software was used to calculate the optimal seam path, check seam topology and create master tiles. SURDEX ortho software generates occlusion/smear polygons used during seam review of steep terrain. SURDEX software was used to visually inspect master tiles for seam and image defects. SURDEX software was used to project and cut final DOQQ image files from masters. SURDEX software was used to create CCM metadata. Lizardtech GeoExpress version 10.0.0.511 was used to create the CCM image file. SURDEX software was used to perform final formatting, QC and naming of the DOQQ.USGS metadata parser software was used to validate the metadata. Various versions of Microsoft Windows were used in all phases of production. Grouping Tool was used again after DOQQ and CCM production to provide a quality assurance check. Individual DOQQ and CCM may not meet the USDA APFO Image Metrics ranges due to land cover. The goal is to have the state as a whole meet the Image Metrics. All products are reviewed by independent personnel prior to delivery. The delivery is checked for omissions, commissions, naming, formatting, specification compliance and data integrity