Aerial photogrammetry is a technique used to obtain reliable measurements of objects from their photographic images captured from aircraft. It involves taking precise photographs of terrain from an aircraft flying over an area. The photographs are then used to measure heights, areas, lengths, and densities of objects. Aerial photogrammetry has many applications including geological investigation, soil surveys, urban and regional development planning, transportation systems planning, and assessing shore erosion. Its key advantages are the ease and speed of data collection from a broad view, and that the results are highly accurate. Its disadvantages include needing light to work and susceptibility to digital data loss or hacking.
2. PHOTOGRAMMETRY:
Photogrammetry is a surveying and mapping technique which
can be used in various applications. There are many uses of
Photogrammetry in the surveying industry such as topographic
mapping, site planning, earthwork volumes, production of
digital elevation models (DEM) and orth photography maps.
Photogrammetry describes from three words:
photo light
gram drawing
metry measurement
The output of photogrammetry is typically a map, drawing,
measurement, or a 3D model of some real-world object or scene.
3. AERIAL PHOGRAMMETRY
AERIAL PHOTOGRAPH:
Photographs taken from a platform, usually an
airplane , flying above the earths surface.
Can be taken from space but usually taken from within
the atmosphere.
TYPES OF AIR PHOTOS:
Vertical air photos
Vertical or nearly vertical angle to the local ground surface
Oblique air photos
Tilted away from vertical
High oblique Low oblique
5. Photographs of terrain in an area are taken by a precision
photogrammetric camera mounted in an aircraft flying over
an area
AERIAL PHOGRAMMETRY
AERIAL PHOTOGRAMMETRY
Technique of obtaining reliable measurement of objects
from their photographic images.
Height of object
Areas
Lengths
Density
6. Geological investigation
Soil survey
Urban and Regional Development
Transportation system
Shore erosion
AERIAL PHOGRAMMETRY
USES
7. AERIAL PHOGRAMMETRY
ADVANTAGES:
The foremost advantage of photogrammetry is the ease and speedat
which the data can be collected.
The photogrammetric techniques yield results that are highly
accurate making it very reliable to use for mapping or other purposes.
It offers a wide or broad view of the mapped area by utilizing both
topographic and cultural features of the land surface.
DISADVANTAGES:
The major disadvantage is that the photogrammetric survey is not
possible in the absence of light.
The accuracy of the measurements depends highly on the flight
height.
The digital aspect of the photogrammetry surveys makes it susceptible
to hacks and loss of data due to viruses.