Photography comes from greek words phos[light] and graphien[writing]. The advent of modern photography has traveled over a millennium, since 10 century AD when Al Hazen of Basra explained the principles of Camera Obscura. In the last century we had U2, the US spy aircrafts taking photographs from altitude of 60,000 ft providing images having ground resolution of 76cm in 1950s. The next leap was with the first instance of Satellite Photography in 1960 when Corona, the US spy satellite started taking satellite photographs. The decades which followed, must have been the heydays of aerial photogrammetry. Although it was/is still restricted in many countries, due to the national security implications, but the National Mapping Agencies covered the large part of their respective countries through aerial photography.
As an exercise to have a comparative scenario of current status of photogrammetry in various parts of the world, a request was sent to many national surveys/companies around the world dealing with aerial photogrammetry, which drew a weak response. Just five countries responded! This is surely not a reflection of the lack of penetration of this technology but rather the very high national security concerns associated with aerial surveys in many countries. A perceived threat about high resolution data outflow has prevented government-private collaboration in this area. The equations may change in face of impending developmental projects which need aerial surveys and also due to the ‘eye opening’ high resolution satellite imagery readily available for a price. But, it is sad for many of the countries, where policies have been prohibiting private industry players to carry out aerial photography for mapping, where the industry continues to miss out the excitement of aerial photogrammetry for mapping works.
During the early 1970s, we had a new option for earth observation and geospatial data, the satellite remote sensing. In terms of ground resolution, it was and still it is far more course than aerial photography, which may have made the policy makers adopt a not so restrictive approach towards satellite remote sensing. It makes me feel that for the aerial photographs, ‘Too Good’ at times is ‘Too Bad’.
Another sibling of aerial photography, LiDAR, is now finding many advantages over it, with the user segments. In most of the LiDAR surveys today, an aerial digital camera is mounted alongside. The need, many a times, is for a reusable visual record which is all the digital camera will provide. In this issue, we have a summary of the NOAA report on the Asian Remote Sensing Market (Aerial and Spaceborne) by Global Marketing Insight Inc. If it is extrapolated in a global sense, then the picture for the remote sensing and allied industry is quite rosy. The projections for the next five years, forecasts a major thrust for higher resolutions, improved airborne GPS units and technology integration between LiDAR, Digital Cameras and GPS. The last of these is resulting in a waning of the art of aerial photogrammetry – the smooth feel of black anodised handwheels and footdisks of analytical plotters is being replaced by the track ball, and operators of these finely tuned machines will not strain to land the ‘floating dot’ on the terrain model any more.