The chapter “Geodesy and Air Photo Interpretation” provides a thorough introduction to the ideas and applications of geodesy and air photo interpretation. Geodesy is concerned with the measurement and comprehension of the Earth’s shape, size, and gravitational field, whereas air photo interpretation is concerned with the analysis and extraction of information from aerial photos. The chapter begins with a discussion of geodesy and its significance in understanding the Earth’s geodetic reference system. There is information about the ellipsoid, geoid, datum, coordinate system, reference, great circle, spherical angle, spherical triangle, spherical trigonometry, world geodetic system, and Everest spheroid. The next part explores the principles and practices of air photo interpretation. It demonstrates how aerial photographs captured by planes or unmanned aerial vehicles can be utilized to collect spatial data. In addition, it dives into the concept, types, history, and various stereoscopic equipment. The chapter also looks at the various applications of geodesy and air photo interpretation. It highlights the value of topographic mapping, land surveying, and cartography. It also emphasizes their value in environmental monitoring, natural resource management, and other sectors. The importance of geodesy and air photo interpretation in comprehending landforms, plant patterns, land-use changes, and other spatial characteristics is emphasized in the chapter. The chapter finishes by emphasizing the significance of precision, accuracy, and critical thinking in geodesy and air photo interpretation.