Aerial Imagery Collection Services

The vendor is required to provide aerial imagery collection services for include:
- Imagery acquisition and production
1. Flight window
• Acquisition must occur during "leaf-off" conditions, typically between February 15 and April 15. Imagery must be free of snow, ice, flooding, and excessive cloud shadow.
• The board reserves the right to halt acquisition if ground conditions (e.g., late spring leaf-out or significant snowfall) compromise imagery quality.
2. Imagery acquisition
• The name and model number of the sensors and cameras that will be used to acquire digital orthoimagery
• The aerial acquisition flying height that will be used to acquire the imagery.
• The average percentage of endlap and sidelap used to acquire the imagery.
• Describe and provide examples of their minimum and maximum acceptable:
o Sun angle for image collection
o Imagery acquisition time of day
o Ground cover such as snow, fog, smoke, haze, and dust
o Cloud shadow percentage in any one image
o Shadows caused by relief or low solar altitude
3. Imagery evaluation process
• Adherence to the flight plan
• Ground sample distance
• Density
• Contrast
• Hot spots
• Clarity
• Shadow detail
• Building lean
• Overall quality
- Image quality:
• Orthoimagery shall not contain defects such as out-of-focus imagery or inconsistencies in tone and density between individual imagery tiles
• Radiometric distortion – all distortions caused by elevated or depressed structures such as bridges, rail beds, overpasses, and steep terrain must be corrected
• Image mosaicking – there must be no visible seams within the orthoimagery.
• Non-image data - images shall not contain any non-image data like artifacts, titling, and "fill" induced by lack of elevation surface model coverage that results in white, black, or spurious intensity values.
• Pixel classification – no data values must be set to no data values of zero are not acceptable.