JNTU B.Tech III GEOINFORMATICS Previous Question Paper (November/December - 2020 - R16)

Terrestrial photography involves taking photographs from ground-based stations to map or analyze objects. Its advantages include: high precision for close-range measurements, lower operational costs compared to aerial surveys, and the ability to capture details of vertical surfaces or inaccessible areas from a stable ground platform. It is particularly useful for architectural documentation and monitoring structural deformations.

The disadvantages include: limited field of view and coverage area compared to aerial methods, susceptibility to ground-level obstructions like vegetation or buildings, and the requirement for multiple camera stations to cover large areas, which increases the complexity of data processing and image orientation. Furthermore, it is generally unsuitable for large-scale topographic mapping due to the perspective distortion inherent in low-angle terrestrial views.

Small format aerial photography (SFAP) utilizes non-metric, small-format cameras, typically with film or digital sensors smaller than the standard 23 cm x 23 cm format used in professional photogrammetry. These systems are often mounted on light aircraft, UAVs, or kites.

Key characteristics and applications include:

• Cost-Effectiveness: SFAP is significantly cheaper than traditional aerial surveys, making it accessible for small-scale projects and frequent monitoring.
• Flexibility: It allows for rapid deployment and mission planning, enabling users to capture imagery at specific times or under optimal weather conditions that might not be feasible for large-scale commercial missions.
• Spatial Resolution: Because these cameras can operate at lower altitudes, they often provide very high spatial resolution, which is ideal for site-specific studies like precision agriculture, local environmental monitoring, and archaeological prospection.
• Limitations: The primary challenge is the lack of internal geometric stability compared to metric cameras. This requires sophisticated software for image rectification, orthorectification, and bundle adjustment to compensate for lens distortion and the lack of calibrated interior orientation parameters.