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Agricultural mapping in Yemen

Gisat responded to the request of United Nations’ Office for Coordination of Humanitarian Affars (UN OCHA) to provide mapping service for agriculture change assessment in the Sa’ada governorate in the northern Yemen.

Since early 2004, the militant rebels Al-Houthi are in armed conflict with the Yemeni army and government-backed tribal fighters in the governorate. Up to now, six rounds of armed conflicts took place whereas the 6th and latest one lasted from August 2009 until February 2010. Only 2006 could be considered as normal year without fighting with respect to the conflict time scale. In consequence, several inhabitants have been internally displaced from their homes. Continuous fighting and population displacement have had severe impacts on local economy and in particular to agriculture, which is the main source of livelihood in the governorate.

Humanitarian community requires information on development of agriculture production to plan the contingency and humanitarian relief actions. However, insecure situation, extent and remoteness of the governorate area make the field survey infeasible. Moreover, historical information on agriculture state was needed to assess its development.

13 of 15 Sa’ada districts (6,800 km2 in total) comprising more then 95% of governorate’s agriculture land have been mapped using high resolution multispectral imagery. Accurate extent of agriculture land in the governorate including classification into managed/fallow classes was extracted from the imagery together with the key infrastructure and natural features such as road network, settlements and hydrography. By means of automated image classification and computer assisted expert interpretation the status of seeding of fields was then identified for two time horizons: 2006 and 2010/2011. Based on satellite image classification results and auxiliary data such as digital elevation model (DEM) and district boundaries the agriculture change assessment and synthetic analysis had been carried out. GIS-ready vector layers facilitate further analysis and integration in GIS environment. The thematic outputs provide comprehensive, synoptic and coherent information in form of tables, graphs and maps. Thematic maps at scales spanning from 1:40,000 to 1:200,000, vector data and assessment report were provided to the user. They are helpful for understanding and interpretation of agriculture development in the governorate. Utilization of state-of-the-art EO based technology including automation of processing procedures in the framework of proven processing chains and methodologies ensures repeatability and operability of the service.

The service has been appreciated by UN OCHA experts as it clearly showed the benefits of utilization of EO data and EO-based products for agriculture change assessment application. Utilization of the mapping products will return in practical consequences of the fact that activities of humanitarian community could be supported by accurate and up-to-date information.

The service has been provided in the frame of the SAFER (FP7 EU-funded project responsible for the development of the pre-operational GMES emergency management service). Mappings in non-rush mode (emergency support services) serve to support preparedness and prevention as well as recovery activities and long-term development projects of humanitarian community.

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