Geography Reference
In-Depth Information
Kite Aerial Photography (KAP)—used for aerial photography (orthophoto,
oblique photography) from ca 200 m altitude in areas where UAV is not
suitable.
6
GPS survey—for identifying the remains/original locations of extinct settlement
and measuring the ground control points for UAV and KAP.
UAV
UAV is a very popular and available method nowadays for collecting spatial data.
A UAV can carry different types of sensors like cameras, multi/hyper spectral
sensors and thermo sensors, LIDAR or precise GPS. The great advantage of a UAV
is the low cost of the equipment compared to manned aircraft, flexibility and
possible repeating of the campaigns in different time periods (Rango et al.
2006
).
Within this project hexa and octo-copters (drone) are used for taking oblique
photography and creating orthophotos of areas of interest. The images are taken
using a calibrated camera and further processed using the Agisoft software
(Verhoeven
2011
).
KAP
KAP is a rather simple way of taking aerial images from ca 200 m altitude. The kite
parameters are the following: one string kite Elliot Rhombus Mega Power Sled, size
300
170 cm, string length ca 250 m, wind acceptance 2-5 Bft. The kite can carry a
Canon PowerShot D10 camera on a special mount (Fig.
2
). The images are taken in
time-lapse ca every 10 s. The kite has to be operated at least by two people (during
take-off/landing, identifying the real camera position in the air). This method is
cheaper in comparison with UAV, applicable by less skilled users but dependent on
stabile wind. It has been proved that during good weather conditions more than
40 % images are usable. During worse weather conditions the amount of usable
images decreases below 20 %. Suitable images are further processed to orthophotos
or used for other land-study purposes (Br˚na
2013
).
KAP was used to study the landscape and for identifying settlement relics in
abandoned villages located at the border with Germany. The first stage of this
research was the preparation of old maps for use in a field GPS receiver. Based on
the information contained in the old maps, the boundaries of the former settlement
were identified and staked. The KAP survey was performed in early October as the
vegetation was low and the weather conditions up in the mountains (ca. 900 m)
6
Areas unsuitable for UAV may be considered as a high windy area or an area with legislative
problems (borders with another country). KAP may be used as well when a person is not licensed
to fly an UAV.
