AERIAL PHOTOGRAPHY

■ Definition and equipment

Aerial photography is the taking of photographs of the ground from an elevated position.

Aircraft utilised for aerial photography include airplanes, helicopters, balloons and drones. Model aircraft and drones are usually used to carry out low-altitude aerial photography. because they are suitable in any situation in which it would be dangerous to operate with a full-size aircraft.

■ Use of aerial photography

Aerial photography is used in photogrammetric surveys, which are the basis for topographic maps, land planning, archaeology, environmental studies and very often for police surveillance.

Aerial photographs may be directed vertically creating orthophotos which are photographs taken from an infinite distance, looking straight down.

Orthophotos are commonly used in Geographic Information Systems (GIS) in order to create maps. To do this, the images have to be “registered” with real-world coordinates. Large sets of orthophotos, derived from multiple sources and divided into ‘tiles’ (each 256×256 pixels in size), are widely used in online map systems such as Google Maps* .

■ Professionals

Photogrammetrists and cartographers’ work involves everything from carrying out geographical research and compiling data to producing maps. They collect, analyse and interpret both spatial data (latitude, longitude, elevation and distance) and nonspatial data (for example: population density, land-use patterns, annual precipitation levels and demographic characteristics). The maps may be in either digital or graphic form, using information provided by land surveys and remote sensing systems including aerial cameras, satellites and LIDAR.

■ LIDAR

LIDAR* is the acronym for “Light- Imaging Detection and Ranging”. This system uses lasers attached to planes and other equipment to digitally map the topography of the Earth. It is more accurate than traditional surveying methods. Data developed by LIDAR can be used by surveyors, cartographers and photogrammetrists to provide spatial information to specialists in geology, seismology, forestry, construction, environment and other fields.

7 Decide if the following statements are true (T) or false (F) and correct the false ones.



T F
1. Aerial photography uses both model
and full-size aircraft.


2. Photogrammetric survey is only used
for land planning.


3. Orthophotos are used to create online
map systems.


4. Orthophotos do not need real-world
coordinates.


5. Cartographers collect and interpret
both spatial and non-spatial data.


6. Data can be provided by land surveys
and aerial cameras.


7. The goal of LIDAR is to take digital photos
of the Earth’s surface.


8. The information provided through LIDAR
may be used only for cartography.


8 Ask and answer the following questions in turns.
1. What aircraft are utilised for aerial photography?
2. What are photogrammetric surveys used for?
3. When and where are model airplanes and drones usually used?
4. What is an orthophoto?
5. What are orthophotos used for?
6. What procedure is carried out in order to create online maps?
7. What kind of activities do photogrammetrists and cartographers carry on?
8. What system is used in LIDAR surveys?

9 Watch Joseph Kirksey, an expert geographer, talking about GIS and complete the sentences below.
What is GIS? posted by Our Earth
1. GIS is all about solving ........................................... in our world, from local to ........................................... .
2. Any problem that has to do with the ‘...........................................’ question.
3. Problems about earthquakes, ..........................................., floods, ..........................................., energy, ..........................................., migration, and ........................................... are all connected to spatial information.
4. GIS is composed of ........................................... and ............................................ That software is up in the Cloud or on the web.
5. The software used by GIS includes ........................................... data, maps and satellite ............................................
6. We have increased pressure on the ........................................... and we have increased ............................................
7. Tools, ........................................... and networks of people can make a difference, solve ........................................... in a decision-making environment, in ..........................................., non-profit private industry.
8. GIS is making our world more ..........................................., healthier and ............................................

Landmarks
Landmarks
Libro digitale in formato "liquido"