Recovery of the aerial photographs of Ethiopia in the 1930s

Nyssen, Jan; Petrie, G.; Mohamed, Sultan; Gebremeskel, Gezahegne; Seghers, Valérie; Debever, Martijn; Hadgu, Kiros Meles; Stal, Cornelis; Billi, Paolo; Maeyer, Philippe De; Haile, Mitiku; Frankl, Amaury

doi:10.1016/j.culher.2015.07.010

Cited by 18 publications

(22 citation statements)

References 16 publications

(13 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For this analysis we used the central part (average scale of 1:11 500) and low‐oblique part (1:13 000–1:18 000) of the aerial photographs that the Italian Military Geographical Institute took over the study area in 1935–1936 (Nyssen et al ., ) as well as the corresponding site on Google Earth in 2014. Google Earth images of the study area for the period from December 2013 to February 2014 are based on Pleiades 1A and Pleiades 1B satellites (2 m resolution) and SPOT 6 satellite (1.5 and 6 m resolution).…”

Section: Methodsmentioning

confidence: 99%

Gully and soil and water conservation structure densities in semi‐arid northern Ethiopia over the last 80 years

Guyassa

Frankl

Zenebe

et al. 2018

Earth Surf Processes Landf

Self Cite

View full text Add to dashboard Cite

Gullies have been a common phenomenon in semi‐arid northern Ethiopia for the last centuries. However, soil and water conservation (SWC) structures have been implemented for a long time to curb soil erosion. Though, like most of the affected areas worldwide, density and distribution of gullies and SWC structures, their causes and interrelations are poorly understood. The aims of this study were to develop a technique for mapping these densities of gullies and SWC structures, to explain their spatial distribution and to analyze changes over the period 1935–2014. Aerial photographs from 1935 to 1936 and Google Earth images from 2014 of the 5142 km2 Geba catchment were used. Transect lines were established to count gullies and SWC structures in order to calculate densities. On average, a gully density of 1.14 km km−2 was measured in 1935–1936 of which the larger portion (75%) were vegetated, indicating they were not very active. Over 80 years, gully density has significantly increased to 1.59 km km−2 with less vegetation growing in their channel, but 66% of these gullies were treated with check dams. There was c. 3 km km−2 of indigenous SWC structures (daget or lynchets) in 1935–1936 whereas a high density (20 km km−2) of introduced SWC structures (mainly stone bunds and terraces) were observed in 2014. The density of gullies is positively correlated with slope gradient and shrubland cover and negatively with cropland cover, whereas the density of SWC structures significantly increased with increasing cropland cover. Density maps of gullies and SWC structures indicate sensitive areas to gully formation and priority areas for the implementation of SWC structures in Geba catchment. The obtained results illustrate the feasibility of the methods applied to map the density of gullies and SWC structures in mountainous areas. Copyright © 2018 John Wiley & Sons, Ltd.

show abstract

Section: Methodsmentioning

confidence: 99%

Gully and soil and water conservation structure densities in semi‐arid northern Ethiopia over the last 80 years

Guyassa

Frankl

Zenebe

et al. 2018

Earth Surf Processes Landf

Self Cite

View full text Add to dashboard Cite

show abstract

“…Nyssen et al . () provide a full description of the recovery and digitization of the archive. In short, a camera with a focal length of 178 mm was used with a target flying height of between 4,000 and 4,500 m a.s.l., yielding an approximate scale of 1:11,500.…”

Section: Methodsmentioning

confidence: 99%

“…The aerial photographs were originally acquired by the Istituto Geografico Militare during the period of Italian occupation of Ethiopia (1935)(1936)(1937)(1938)(1939)(1940)(1941) and are presumed to be the oldest air photos of East Africa. Nyssen et al (2016) provide a full description of the recovery and digitization of the archive. In short, a camera with a focal length of 178 mm was used with a target flying height of between 4,000 and 4,500 m a.s.l., yielding an approximate scale of 1:11,500.…”

Section: Datamentioning

confidence: 99%

The Resilience of Ethiopian Church Forests: Interpreting Aerial Photographs, 1938–2015

et al. 2016

Self Cite

View full text Add to dashboard Cite

Church forests collectively represent the only surviving remnants of the original montane forest, serving as critical sanctuaries for many of Ethiopia's endangered and endemic plant and invertebrate taxa. Modern inventories of church forests suggest that they are vulnerable to degradation because of their small size and isolation. The aim of this study is to use historical air photos from the period of the Italian occupation of Ethiopia (1935–1941) to measure changes to church forests over a ~80‐year time span. We find little evidence that church forests in the study region around Debra Tabor in the northern Ethiopia highlands are declining in size. Rather, church forests have proven to be remarkably resilient on the landscape despite decades of dramatic change to the world around them. Our findings, therefore, highlight the effectiveness of religion‐based forest stewardship. Results also indicate, however, that while many church forests used to be buffered from intensive agricultural activity (e.g., cultivation and pasture) today, they find themselves significantly more isolated and vulnerable to edge effects as a result of a general decrease of trees and bushlands surrounding the forests. Copyright © 2016 John Wiley & Sons, Ltd.

show abstract

“…These are clear advantages of SfM in processing of archive APs often coming without calibration data over traditional photogrammetry solutions (Frankl et al, ; Kropáček et al, ). A further beneficial development of recent years is an improved archiving and accessibility of APs (Nyssen et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…. A further beneficial development of recent years is an improved archiving and accessibility of APs (Nyssen et al, 2016).…”

mentioning

confidence: 99%

Historical aerial and terrestrial photographs for the investigation of mass movement dynamics in the Ethiopian Highlands

2019

Self Cite

View full text Add to dashboard Cite

The edges of the Ethiopian Plateau are affected by frequent landslides predisposed by pronounced seasonality in precipitation, thick weathering mantle of volcanic material, and rough relief. We analyzed the three‐dimensional dynamics of three large landslides in Dessie using digital elevation models and ortho‐images derived from a time‐series of aerial photographs reaching back to 1936. Furthermore, we utilized repeated photography based on terrestrial photographs from the 1930s and 1940s to analyze landscape changes. It was revealed that the large sliding zone (25.4 ha) in lacustrine sediments at Kerra locality existed approximately in the present extent already before 1936. The volume of depleted material of the 1986–1994 rock slide at Doro Mezleya locality was assessed as 1.82 106 m3 with mean vertical thickness of 48 m. Additionally, we described the nowadays inactive Hot Spring landslide (12.9 ha). We documented a large scale reforestation of the area carried out as a remediation measure and rapid changes in land cover and settlement structure. We conclude that two out of three studied large landslides existed before 1936 and thus are not induced by the increased human pressure on the landscape of the last decades. Additionally, we provide an overview about collections of historical aerial photographs of Ethiopia, and we discuss their potential and drawbacks for mass wasting studies.

show abstract

Recovery of the aerial photographs of Ethiopia in the 1930s

Cited by 18 publications

References 16 publications

Gully and soil and water conservation structure densities in semi‐arid northern Ethiopia over the last 80 years

Gully and soil and water conservation structure densities in semi‐arid northern Ethiopia over the last 80 years

The Resilience of Ethiopian Church Forests: Interpreting Aerial Photographs, 1938–2015

Historical aerial and terrestrial photographs for the investigation of mass movement dynamics in the Ethiopian Highlands

Contact Info

Product

Resources

About