Aerial photography was acquired using a flight design that included a total of 5097 exposures in 48 North-South oriented flight lines. Aerial photography was exposed on Kodak CIR film 1443. Aerial photogaphy was supplemented with the simultaneous acquisition of airborne GPS data, which captured the ground coordinate for the nadir point of each photograph. Aerial photography was exposed at an altitude of 9600' above mean terrain yielding an approximate scale of 1:19600.
Softcopy aerotriangulation utilizes the GPS ground control and image coordinate measurements which are run through bundle block adjustment software computing the exterior orientation parameters for each image of the photogrammetric project. The original aerial film was scanned utilizing a Zeiss precision photogrammetric scanner at a resolution of 14.0 microns. Using these scans the aerotriangulation process employs a rigorous mathematical model which detects measurement errors, and corrects for systematic image distorion, film shrikage, atmospheric refraction and camera lens distortions. The final bundle adjustment results are inspected to ensure that the RMSE meets the required 1 part in 10000.
The procedure utilized for the development of the DTM/DEM development used a combination of automated and manual techniques. The initial phase produced an intermediate terrain data set using a series of automatic data processing algorithms known as Automatic Terrain Extraction. This data set is further refined using a series of automatic filtering techniques, along with visual inspection and editing processes to produce a fully compliant DEM meeting the project specifications. To enhance the results of the ATE process linear and polygonal break line information was collected in all areas where a more rigorous data set was required to define changing terrain conditions. This break line data is then merged into the correlated terrain file and used to influence the DTM by correcting areas where the ATE process has failed to depict the terrain accurately.
Digital orthorectification includes a spatial and radiometric transformation of the scanned image from line/sample space into the specified ground coordinate system. The interior and exterior orientation parameters from the aerotriangulation process are used to project each pixel into the ground coordinate system, while the DEM is used to correct for relief displacement. The CIR orthophotos are generated by Intergraph's Base Rectifier using a cubic convolution algorithm. Once the images are ortho-rectified, they are checked for geometric accuracy and image quality, and tone-balanced. The individual overlapping orthophotos are mosaicked together using Automatic Image Mosaicker (AIM) software into one seamless image data set. Final tiles are then extracted from the image set to the State of New Jersey's tiling scheme.
Original uncompressed TIFF images were processed using GeoExpress to produce a lossless JPEG2000 file for each image.The JPEG2000 files were indexed and a sublayer of a WMS constructed, using Express Server.
Express Server software upgrade and change to URL of service.