As part of a joint project between Ghent University, the Ethiopian Geospatial
Information Institute and Mekelle University, the aerial photographs of the 1930s
have been digitised; about 40% of them could be relocated through comparison
with recent satellite imagery, and have been organised into a searchable inventory.
So far, the aerial photographs of this collection have been used for research at
local scale, addressing changes to rivers, to land use, or to density of soil
and water conservation. Also urban expansion, gully development, church forests
or lake level changes have been studied. But much more remains to be done.
Methods used include the recognition of features by morphology and texture on
the photographs, image restitution through modelling methodologies, or simple
‘rubbersheeting’, counting of number of features for a given area, point-count method...
Aerial photo archive of Ethiopia in the 1930s
The archive of pre-1940 aerial photography of Ethiopia comprises the coverage
of north and central Ethiopia that was acquired during the Italian invasion
of the country in 1935-36 and during the period of occupation. This activity
ceased after the defeat of the Italian army in East Africa in 1941.
The rediscovery of this archive opens new perspectives for change studies as it
is the largest set of pre-1940 APs in Africa.
As a result of an agreement between Ghent University (Belgium), the Ethiopian
Mapping Agency (now Ethiopian Geospatial Information Institute) and Mekelle
University (Ethiopia), all the photographs in the archive have been digitised
at a resolution of 600 spi.
In total, the archive comprises approximately 34,000 individual photographs,
made up of 8281 discrete assemblages, each comprising four adjacent photographs.
Photographs bear no fiducials and merely a two- or three-digit identification number.
An individual set of four photographs comprises a vertical (nadir-pointing)
photograph, flanked by two low-oblique photographs and a single high-oblique
photograph, which is present alternatively at left and right. All four
photographs had been exposed simultaneously in a fan configuration in the
cross-track direction (perpendicular to the flight line) to ensure the
widest possible angular coverage of the terrain.