Poor Internet links mar Africa's satellite data access – “fundamental and serious” obstacle


African satellite images are useful but only if scientists have the means to access and study them A landmark decision to allow free access to key earth observation data has failed to impact Africa sufficiently because of poor Internet connections, say researchers.

The US Geological Survey took the decision to allow free access to Landsat Earth observation satellite data in January 2008 – a deal that opened up nearly 40 years of images, or 'scenes'. The data can be used to monitor changes to the land, such as the effects of climate change on crops, or urbanisation.

But a review of Africa's uptake of the data, published online as a letter to Remote Sensing Letters last month (23 February), has found the lack of Internet connectivity between the United States and Africa to be a "fundamental and serious" obstacle.

It also found a lack of education in remote sensing; poor awareness of how the data could be used and who could use it; and insufficient infrastructure and capacity within countries to allow good use of the data.

The issue of poor Internet access "presents a fundamental and serious current constraint in Africa where the majority of countries have limited internet capability," say the authors of the letter, led by David Roy, a remote sensing specialist at South Dakota State University in the United States.

 "You have this consistent, long-term data record ... that allows you to compare how land use has changed in that time," he said. "But in Africa, Internet connectivity is really limiting researchers' ability to get this free data."

Cheikh Mbow, a remote sensing specialist from the Institute of Environmental Sciences at Senegal's Cheikh Anta Diop University, said: "In Senegal, if I download one scene I do it overnight. In the US I could do at least 50 scenes". Connections within countries are no better, averaging little more than 256 kilobytes per second, which makes downloading a 250 megabyte Landsat scene difficult.

Data from other satellites is easier to access as it can be downloaded directly to satellite receiving stations in Africa as the satellites pass overhead. But there are no Landsat receiving stations in Sub-Saharan Africa as they are prohibitively expensive to build says Mbow, a co-author of the paper.

Undersea cables and terrestrial links will solve the issue say the authors. But "problems of establishing networks within countries and African government regulation may continue to restrict Internet access across the continent.