| Photogrammetry is a scientific method of | | | | areas: |
| measurements using photography. In essence, it is | | | | 1. Far range and Close range photogrammetry. |
| a measurement technology using the | | | | The far and close range depends on the camera |
| three-dimensional coordinates of points on an | | | | lens setting. For example, for close range, the lens |
| object are established through measurements | | | | setting is kept at finite values and whereas for |
| taken using several (two to three) photographic | | | | far range the lens is adjusted to infinite or |
| images taken from different angles. The outcome | | | | indefinite setting. |
| is a map or drawing or a 3-dimensional model of | | | | 2. The Aerial photogrammetry can be considered |
| an actual object or a scene. Most of the maps | | | | as far range, on the other hand, the Terrestrial |
| available today are creation of Photogrammetry | | | | Photogrammetry is used for close range. In Aerial |
| or aerial photos taken using aircraft. Also, it can | | | | Photogrammetry the camera is fixed to an |
| be considered as a reverse process which | | | | aircraft and is adjusted vertically or towards the |
| convert the 2-dimensional photograph to a 3-D | | | | ground. Several multiple overlapping photographs |
| image. | | | | of the ground are captured when the aircraft |
| Photogrammetry is useful:o to establish | | | | glides along a flight path. Once the aerial photos |
| coordinates of the required object-pointso | | | | are taken, these photos have to be processed |
| preparation of topographical and thematically | | | | using a stereo-plotter (which is an instrument that |
| mapso developing rectified photographs or | | | | will allow viewer to see two photos simultaneously |
| ortho-photos.photogram | | | | in a stereo view). These photos are also used to |
| The significant feature of photogrammetry is that | | | | create Digital Elevation Model (DEM) using a |
| without touching the objects measurements could | | | | process. |
| be done. Another form of photogrammetry is | | | | In close range Photogrammetry the camera is |
| Remote Sensing which was mainly focused on | | | | held close to the object and is usually it is hand |
| working with aerial photography and satellite | | | | held or mounted on a tripod. The close range is |
| imaging. On broader sense, it is used for object | | | | commonly used for non-topographic surveys. In |
| interpretation and object measurement. More | | | | other words, it is used to produce drawings or |
| precisely, the Aerial photogrammetry is mainly | | | | 3-D Models and cannot be considered producing |
| used to produce topographical or thematical maps | | | | topographic maps or terrain models. This type is |
| or digital terrain models. The photogrammetry is | | | | commonly used (with normal cameras) to model |
| very popular among architects, civil engineers, | | | | buildings, engineering structures, Vehicles, films, |
| archaeologist, police and military establishments. | | | | etc. |
| The photogrammetry can be classified into two | | | | |