Photogrammetric Mapping IDIQ – Region 3

Project Description

Wiser provided 1776 tiles (8000 x 14000 ft.) of orthophotography covering 15 counties РCheatham, Davidson, Houston, Humphreys, Macon, Montgomery, Robertson, Rutherford, Smith, Stewart, Sumner, Trousdale, Williamson and Wilson County.

Wiser used ImageStation OrthoPro (OrthoPro) to create orthophotography with 12 inch ground pixel resolution from the digital imagery provided by TDOT.

All images were orthorectified using the provided DEMs to remove the effects of the uneven ground surface. Then the orthorectified images were created for mosaicking using ISPM source images that were specified during the project preparation phase. After this the images were tonal balanced and adjusted to ensure consistent quality between photos.

Wiser generated seamlines along which the images were mosaicked.  Wiser reviewed and modified the seamlines to avoid crossing features such as buildings.

After the images were mosaicked and cut into tiles, the tiles were inspected for quality and seamline errors such as shifts between images, smears along seamlines, errors in the DEM surface, unacceptable color variances between images and other conditions that would detract from the smooth transition between images. The orthophotography was also reviewed against provided vector data to ensure that it still met horizontal accuracy. Each tile was also reviewed for edgematching with adjacent tiles including those tiles in adjacent regions and those provided by TDOT and other contractors.

Once all corrections to imagery were completed and verified, Wiser merged the tiles for each delivered county into a single SID image. The individual tiles were delivered at 12 inch ground pixel resolution in TIFF/TFW format.  All data was delivered in Tennessee State Plane NAD 1983, U.S. Survey Feet, NAVD 1988 coordinates.