Nadir and Zenith in Satellite Imagery
Nadir is the point directly below a location, while zenith is the point directly overhead. Nadir images are taken vertically downwards, providing undistorted views for mapping and surveying.
Nadir Angle and Satellite Altitude
In satellite altimetry, the nadir point determines the satellite’s altitude, influenced by factors like orbit. Different satellite orbits result in varying nadir angles.
Medical and GIS Applications of Nadir
In oncology, nadir denotes the lowest blood cell count during chemotherapy. In GIS, nadir refers to the direction pointing directly below a location.
Oblique vs. Nadir Imagery
Oblique imagery is taken at an angle different from nadir, offering unique perspectives for 3D representation. Combining oblique and nadir imagery enhances mapping accuracy.
Challenges and Solutions in Nadir Imaging
Difficulties in photographing nadir images include potential damage to the nadir area. Maintaining the lens’s nodal point position is crucial for consistent image quality.