These files contain 2007 digital Ortho-imagery of Tompkins County, New York. Image pixel size is .5 ft. GSD. Image type is Natural Color. Image horizontal accuracy is within 2 ft. at the 95% confidence level (NSSDA). Each file contains an image covering 3000 ft. by 2000 ft. on the ground.
This digital Ortho-imagery can serve a variety of purposes, from general planning to field reference for spatial analysis to a tool for revision of vector maps. It can also serve as a reference layer for GIS.
Use of sensitive imagery, if granted, is only for the use specified in the request.
30 South Pearl Street
NYS Cyber Security
The dataset contains raster images or digital ortho images so the logical consistency report is not applicable. The file naming convention was supplied by New York State. When the ortho tiles were created the file names were restricted to a numeric value representing the lower left corner of the ortho tile. These tiles were then all renamed using a batch script so that they reflected the N.Y. state standard (i.e. "c_10470162_12_09600_col_2006.tif"). Consistency of file naming was ensured by using a batch process. The file naming convention consists of the first letter for Central, East, West or Long Island for New York State Plane Coordinate Systems (NYSPCS). The following four numeric characters represent the first four characters of the "X" coordinate value for the tile's lower left corner coordinate in NYSPCS and the next four characters represent the first four characters of the "Y" coordinate value for the tile's lower left corner coordinate in NYSPCS. The next two numeric characters represent the tile's Ground Sampling Distance (GSD) value in inches. The following five numeric characters represent the Above Mean Terrain (AMT) nominal height at which the DMC sensor recorded or collected the original imagery for the corresponding area. The next three characters are "col" for Digital Natural Color ortho-photos and "cir" for Digital Color Infrared ortho-photos. Lastly, the last four numeric digits represent the year in which the particular ortho was created.
The project consisted of 418 final tiles.
The Digital Natural Color aerial imagery was acquired in Spring 2007 using a DMC sensor flown at a nominal height of 19200 feet AMT (Above Mean Terrain). ABGPS data was also collected supplemented by New York State CORS data. The Ground Control used to support the Digital Natural Color Ortho-imagery production was collected by identifying strategic points on previous aerial photography and supplemented by selecting new points or photo identifiable points (PID) in areas where needed due to a lack or minimal existence of points from previous Ortho-imagery production projects and then determining the precise location coordinates of the entire ground control network by using ground survey techniques. The new Ground Control Network was also supplemented by targeting existing New York State HARN stations data. The Digital Aerial Triangulation (DAT) was performed, primarily, using softcopy workstations and Intergraph's ISPM software. DAT solutions were independently reviewed and checked using independent blind control points. Digital Elevation Models (DEM) (mass-points and break-lines) used to support ortho imagery production were created using standard photogrammetric collection techniques on Intergraph's SSK soft copy workstations. The images were then ortho-rectified and color balancing was performed using Intergraph's OrthoPro software. Seamless mosaicking was performed by manual seam line creation using Intergraph's IRASC software and then importing them into OrthoPro for mosaicking. Images were then color balanced again in order to match adjacent counties projects and quality controlled using Intergraph's IRASC, OrthoPro and Adobe PhotoShop software. The seamless mosaic was clipped into tiles using OrthoPro software. The imagery product deliverables are GeoTIFF images with embedded header information describing the required projection, pixel size, tile size and other related data and corresponding world files (.tfw). Final files were then compressed to JPG2000 files (.jp2) with corresponding world files (.j2w) at a compression ratio of 20:1 using Lizard Techs GeoExpress v6.0 software. All .jp2's require MapInfo .tab files.