Abstract:

These files contain 2005 digital orthoimagery of Montgomery County, New York. Image pixel size is 2 ft. GSD. Image type is Panchromatic. Image horizontal accuracy is +/-8 ft. at the 95% confidence level.  Each file contains an image covering 6000 ft. by 4000 ft. on the ground.

Purpose:

This digital orthoimagery 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.

Supplemental_Information:

Digital elevation models used for orthorectification were compiled from several sources, all of which were compiled photogrammetrically.

Currentness_Reference:

ground condition

Use_Constraints:

Use of sensitive imagery, if granted, is only for the use specified in the request.

Address:

30 South Pearl Street

Data_Set_Credit:

NYS Cyber Security

Logical_Consistency_Report:

The dataset contains raster or digital ortho images so the logical consistency report is not applicable. The file naming convention was supplied by New York state and is based on the co-ordinate pair of the lower left corner of the ortho tile. When the ortho tiles were created the file names were restricted to a numeric value representing the lower left corner of the ortho tile. 10470162 represents a tile with the lower left corner of 1047000, 162000. These tiles were then all renamed using a batch script so that they reflected the N.Y. state standard e_10470162_24_14400_pan_2004.tif Consistency of file naming was ensured by the batch process.

Completeness_Report:

The project consisted of 564 final tiles

Horizontal_Positional_Accuracy_Report:

+/-8 ft. at the 95% confidence level (NSSDA)

Vertical_Positional_Accuracy_Report:

Not applicable.

Process_Description:

1:28,800 scale aerial photography with airborne GPS was acquired April 14 to May 17, 2005 with a LMK1000 aerial amera system equipped with six inch focal length lens. The imagery was scanned at 14 microns directly from the aerial negatives.
The aero triangulation process utilized an airborne gps survey undertaken during the flight to provided geodetic coordinates and elevation of photo centers. Also, image targeted ground control points where visible on the 2005 aerial flight and were used as control. Aerial triangulation was performed using softcopy workstations and Mira Solutions AT bundle adjustment program, Mira-AT. Details of the aerial triangulation process can be found in the Montgomery County, New York 2005 Orthophoto Update Project Aerial Triangulation Report.
For the 2002 orthophoto project only minimum DTM was collected in the center area of each aerial photo model creating an uneven distribution of terrain data throughout the project area. This process created what has been called "donut-holes" in the DTM and limited the usefulness of the data set for future ortho photo projects and other applications for this level of DTM. The 2005 project requirement was to fill in these sparse areas of DTM to create a consistent pattern digital terrain points throughout the project area. This was done by using a softcopy workstation with the AMSA-Softcopy program, overlaying the existing DTM on the stereo model and then adding points or breaklines to create a uniform level of digital terrain data. During this process the aerial photography was inspected for new roads and bridges that required collection of a bridge polygon that was used to correct the shape of the bridge during the orthophoto process. The photo inspection was assisted by information provided by Montgomery County as to the location of new roadways since 2002.
The images were then ortho rectified using Mira Solutions Mira Ortho software. Mira Solutions Mira Mosaic program was used for the mosaicking, color balancing and tiling of the imagery. The Mira Solutions process produced the same effect for bridges as was required to meet the previous ortho photo project. Quality
control was maintained throughout the process using internal QA programs within the Mira Solutions suite of orthophoto production software. Final files were then compressed using MrSID. Final deliverables in TIFF format with TFW files and MrSID files where placed on DVD Media.

Address:

30 South Pearl Street

Montgomery County 24-inch Resolution Panchromatic Orthoimagery