High Resolution Aerial Imagery and LiDAR Services

The Vendor is required to provide high resolution aerial imagery and light detection and ranging (LIDAR); for topographic mapping, preparation of digital elevation models (DEM) and digital terrain models (DTM), gathering of color aerial photography and orthophotographs since 1998.
- Technical specifications:
• Recover existing field survey control monuments used in the 2011, 2017, and 2019 surveys and verify stability
• Collect independent ground-truth checkpoints in multiple, spatially dispersed locations to support vertical accuracy validation consistent with asprs 2024 standards.
• Lidar and aerial imagery shall be acquired simultaneously or within 48 hours to ensure dataset temporal consistency
• Orthophotos and LIDAR tiles shall be generated using the same tiling scheme and naming convention used in the county’s 2011, 2017, and 2019 surveys to ensure compatibility with historical datasets.
• Aerial imagery shall include four spectral bands
• Classified point cloud files shall include bare earth; low, medium, and high vegetation; buildings and structures; bridge decks; first returns; water; and high/low noise.
• Lidar data shall be collected at a minimum density of two points per square meter with a nominal pulse spacing (ANPS) of 0.70 meters, consistent with USGS quality level 2 (ql2) requirements.
• Positional accuracy requirements shall follow the society for photogrammetry and remote sensing (ASPRS) positional accuracy standards for digital geospatial data, 2nd edition (2024).
• Aerial imagery shall be three-inch pixel resolution or finer.