Blog Post

Land Use Changes in Central & South Asia Illustrated by Satellite Imagery

16 December 2020
Satellite remote sensing offers unique opportunities to investigate land use changes at large geographical and temporal scales. A valuable source of historical data are the recordings of the CORONA satellites, collected between 1960 and 1972 [1]. Comparing this historic imagery to data recorded by the Sentinel-2 satellites in 2020 are an impressive illustration of anthropogenic related changes of the landscape:




Tajikistan


The Qubodiyon District is located in the southern part of Khatlon region, in the valley of Vakhsh river. The agriculture of the district is mainly characterised by cotton cultivation, which was established as a monoculture farm practice during the Soviet Union era. In a comparison between a historic satellite image taken in 1964 and a most recent image recorded in 2020, the crop area expansion introduced during the Soviet Union period becomes evident (see red line). The irrigation system introduced during the Soviet Union period has largely modified the landscape of the area by transforming arid land into cropland. Consequently, such agricultural development resulted in an expansion of urban areas. The illustrated land use change around the village of Garavuti affected approximately 100 km² (see red line in 1964 and 2020) In addition, the structure of farmland has changed from large homogeneous fields to a more fragmented appearance. This change of farmland structure can be related to farm restructuring following the collapse of the Soviet Union.



Kazakhstan


The Panfilov District is located in the eastern part of the Almaty Region, close to the border between Kazakhstan and the People's Republic of China. The development of the area is closely linked to the Ili River and related irrigation systems for agricultural activities, mainly the production of maize. The maps show the city of Zharkent for two time steps, the major urban centre of the region. The urban expansion from 1968 to 2020 is clearly visible (see red lines). This can be associated with a doubling of the population from 19,173 inhabitants to 42,617 from 1970 to 2019 [2]. Noticeable is not only the increase in area occupied by urban infrastructure, but also the increased built-up area density. Similar to the case study presented for Tajikistan, the structure of farmland has changed from large homogeneous fields to a more fragmented appearance, due to the dissolution of large-scale farms.



Pakistan


The Multan Division is located in South Punjab, Pakistan, and is a major production area for cotton. The location of the map is situated in the south of the city Multan, a major economic and cultural centre of the region. A comparison between 1967 and 2020 shows that the checkerboard-like pattern of agricultural fields is still present in most of the areas. This field pattern can be attributed back to colonial land allotment schemes and canal colonies in pre-partition Western Punjab that led to expansion of irrigated agriculture. In the western part (red arrows), large parts of the area is used for agriculture in 2020, previously been unused for agricultural production.






Sources



[1] Casana, J. (2020). Global-Scale Archaeological Prospection using CORONA Satellite Imagery: Automated, Crowd-Sourced, and Expert-led Approaches. Journal of Field Archaeology, 45(sup1), S89-S100.


[2] http://pop-stat.mashke.org/kazakhstan-cities.htm (accessed December 1, 2020)


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