That was the challenge undertaken by GIM, a Belgian company specialised in processing VHR imagery for urban applications, in partnership with eHealth Africa, an NGO that has their headquarters in Nigeria and works across West Africa. This mapping effort took place as part of the framework of the Global Polio Eradication Initiative, with active participation from the World Health Organisation and UNICEF together with the Nigerian local government authorities.
Supporting Polio Eradication with Satellite Imagery
In Nigeria - one of only three polio-endemic countries left in the world - 122 new polio cases were identified in 2012. Only prevention can help make a lasting difference. To achieve full eradication of this disease, an exhaustive vaccination programme needed to be implemented across the entire country within a very short timeframe. To reach every child, vaccination campaigns can benefit from using satellite imagery. Indeed, mapping all types of settlements using satellite imagery can help foster more efficient deployment of health professionals and ensure no village is missed.
To achieve its ambitious goal, GIM leveraged their partnership with Airbus Defence and Space to collect spatial data over 225,000km² in Nigeria. The objective was to create a fresh and accurate map of all human infrastructures in order to have a comprehensive view of places and people to target. Within the project’s defined timeframe fresh imagery needed to be acquired to develop the map and implement GIM’s ambitious mission.
1st Stage: Fresh and Highly Detailed Data
From single huts to large cities, including roads and rivers, all features had to be visible on the end-users’ map. OnePlan was identified as the most appropriate One Tasking option to acquire high-resolution images using the 50cm resolution Pléiades sensor to cover the extensive area within the project’s defined timescale. One challenge was to meet GIM’s need for extremely detailed, but also fresh data to make a most accurate assessment.
In September 2013, Pléiades satellites were tasked over the Nigerian region. Within the record timeframe of 30 days, an immense area of 50,000km² was acquired. This collection was then further extended to meet GIM requirements.
2nd stage: An Updated Map, Perfectly Matching GIM’s Needs
GIM leveraged its in-depth expertise in Object-Based Image Analysis (OBIA) to process the orthorectified and pansharpened imagery. This data was processed in record time and the end-user, eHealth Africa, provided with a constant flow of information supporting the vast immunisation campaign.
The spatial imagery offered very high-quality visual information to establish an updated map covering an area of 100,000km² depicting 500,000 buildings, 20,000 villages, 1,500 cities and many roads, tracks, lakes and rivers; contributing to not missing a single child at risk of catching polio.
Caption: Small villages close to the city of Gurda, Bauchi State, Nothern Nigeriaright: Kaduna City, Kaduna State, Northern Nigeria
3rd stage: Speculative Tasking for Optimising Local Interventions
The World Health Organisation (WHO) declares a country cleared of the disease only after three full years with absolutely no trace of the virus, whether among the population or in the environment.
Airbus Defence and Space therefore launched speculative acquisition over Northern Nigeria, where the virus used to be active, and Pléiades has covered 178,000km² over this region. Local organisations are now able to optimise their physical interventions by using this fresh data as soon as needed and with a high standard of support.
OnePlan increased efficiency of the vaccination planning: Employing Pléiades through OnePlan facilitated the reliable delivery of the right qualified coverage within the specified timeframe, which perfectly matching project milestones and was completed on time and on quality. Systematic extraction of all human features: Pléiades 50cm mapping product is an efficient solution to create comprehensive mapping.
Guaranteed of a genuine partnership: the collection plan was initiated hand in hand with GIM from the beginning in order to determine the level of priorities fully consistent with the vaccination planning and roll out. The speculative acquisition also anticipates – and guarantees immediate availability of the updated basemap whenever needed – and at a reduced cost.
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