The aerial film was acquired in April 2004. The imagery was scanned at 14 microns using a Z/I Imaging PhotoScan 2000 scanner. The Ground control used to support the ortho mapping was collected by either paneling and targeting of permanent monuments or photographic identification of strategic points. The coordinates were collected via ground survey techniques. The Aerial Triangulation was performed on softcopy workstations using Leica Orima software. The final bundle adjustment was performed using PAT-B software. Digital Elevation Models were updated from previous, year 2000, Westchester County DTM. The northern border DTM was provided by VARGIS (Putnam County). The west border DTM was provided by VARGIS (Rockland County). DTM outside the County boundary on the CT and NYC sides was stereo-compiled from the 2004 imagery.
All DTM were reviewed for changes to the terrain and updated on softcopy workstations using the 2004 photography. All bridges were modeled in 3-D to properly rectify them on the imagery. They were captured using standard photogrammetric stereo-compilation techniques on softcopy workstations. Sanborn's Metro process is able to rectify bridges with the same methodology used to model all other ground features. The bridges area coded uniquely and later removed from the final DTM file. The images were ortho-rectified using METRO, Sanborn's proprietary software. Color balancing was performed using METRO_NICE software. The resulting images are seamlessly mosaiced into orthophoto tiles. Images were quality controlled using Adobe PhotoShop software. Final deliverables in geotiff format with tfw files and metadata files where placed on DVD Media.