As high-resolution satellite imagery from civilian sources becomes cheaper and more accessible, human rights activists and environmental organisations are increasingly using it to uncover and investigate instances of abuse around the globe. Olivia Edward of Geographical magazine reports...

The village of Angabo, Darfur, Sudan, on 21 June 2006. Angabo is one of a cluster of villages that was reportedly burned following the Darfur Peace Agreement in May 2006. This first attack was followed up six months later on 11 November 2006 by a larger attack that resulted in the burning of villages and an unspecified number of casualties. Two days later, the Janjaweed and Sudanese troops reportedly burned the village’s water centre and killed eight civilians. A comparison between this image and another taken on 15 February 2007 as part of Amnesty International’s Eyes on Darfur project revealed that more than 550 structures within the village had been completely burned, mostly in close proximity to the village centre.

In May 2009, as the Sri Lankan army closed in on a rebel Tamil group in the country’s northeast, reports began to come in of a ‘bloodbath’, with more than 10,000 civilians killed. A UN spokesman accused the government of being responsible, but with outsiders banned from entering the area, it seemed unlikely that it would ever be held accountable.

However, ‘someone’ had been ‘watching’: a US-owned satellite. When geospatial experts at the American Association for the Advancement of Science (AAAS) were asked by Amnesty International and Human Rights Watch to analyze images of a civilian safety zone, the truth began to be revealed.

The refuge area was located on a sandy spit, and as the analysts began comparing images taken a few days before the clash with those taken afterwards, they not only saw destroyed buildings and freshly dug graves, they also noted a series of craters dotted across the sand. “They were shell holes,’ says Susan Wolfinbarger, a geographer who has recently taken over as head of the AAAS’s Geospatial Technologies and Human Rights Project. This meant that someone had been firing into the civilian safety zone. But who?

Apportioning blame in such situations is understandably difficult, but in this case, the shells had fallen into soft sand, producing tell-tale ‘ejector’ patterns. A closer inspection of this spewed-out sand indicated the direction from which the shells had been fired. And when those trajectories were traced back, they led directly to areas where the Sri Lankan government forces were thought to have been present.

It wasn’t the whole story — eyewitness and UN reports suggested that civilians were coming under fire from both government and rebel forces — but it provided a rare glimpse of what was really going on in an area from which journalists and researchers were banned.

Dark Corners
With more and more satellites in the sky, and the price of high-resolution satellite images dropping, remotely gathered imagery is increasingly being used by the UN and NGOs to investigate allegations of human rights and environmental abuse. “It’s like a light shining into the dark corners of the world,’ says Mark Brender, chief executive of the GeoEye Foundation, which provides free imagery to NGOs from satellites that belong to GeoEye, a commercial organization that sells satellite and aerial imagery to everyone from governments to Google.s

The commercial availability of high-resolution satellite imagery is a relatively recent phenomenon, only really taking off since the turn of the millennium, but it has already facilitated the investigation of a range of events and issues, including the destruction of homes in Sudan and Zimbabwe, and the environmental effects of the notorious Rio Tinto gold and copper mine in Papua.

“Gathering information in these places is often incredibly dangerous,” says Dr. Chris Lavers, a remote-imaging expert based at the University of Plymouth who has been helping organizations such as Amnesty and tribal-rights NGO Survival. “Journalists have been killed trying to approach the Rio Tinto mine, and aid workers can be targeted as they fly into remote areas in Sudan. Satellite imagery means that we can find out what’s happening in these areas without risking people’s lives.”

But analyzing remote satellite imagery isn’t like looking through a series of CCTV tapes. There’s still a lot of detective work involved, explains US geographer Lars Bromley of UN unit UNOSAT, who was brought in by the UN to strengthen its human rights monitoring work through the use of remotely gathered data.

“A lot of people think that there’s a satellite above their head every moment of the day, and that it’s simply a matter of calling in these images to find out what’s going on, but there are only about five or six satellites that we can use for this sort of work and they only cover a very finite area of the Earth every day,” he says. “The resulting satellite images are really only a snapshot, taken in a picosecond [one trillionth of a second], so you don’t get ‘smoking guns’, such as a burning Sudanese village surrounded by a group of militants in government jeeps.”

And there are plenty of other challenges involved in the process. “The first thing we have to do when we’re asked to investigate an event that has occurred in a particular place is to find out where that place is,” says Wolfinbarger. “And that’s not always as easy as it sounds.’

Recently, when the AAAS team, at the time led by Bromley, was asked to look at a problem in Myanmar, they had to resort to using old Russian topographic maps because the military regime had changed all of the country’s place names. “It has become a lot easier now thanks to Google Earth, which includes some really remote places but, in the past, sometimes we’ve had to say, “Sorry, we can’t investigate such and such a place because we can’t find its coordinates,” says Wolfinbarger.

Once a place has been located, analysts usually hope to acquire a set of before and after images that they can compare for evidence of wrongdoing. Ideally, these images will be held in the archives of satellite-imaging companies, but the imagery will only be available if someone else has already commissioned it, so the less attention a conflict has received, the less likely it is that images of it will exist.

If there are no archive shots, new images can be commissioned for around one sixth of the price of an archive image. “They cost around US$2,000 each,” says ß. “And then when you get them back, there’s always the worry that the one village you want to look at will have a cloud over it.”

If the skies above their chosen area are clear, analysts can begin comparing the before and after shots to see how an event has transpired. In Zimbabwe in May 2005, president Robert Mugabe’s government began a campaign called Operation Restore Order or Drive Out Trash, in which the homes of about 700,000 people were demolished. Images taken after some of the 10,000-plus residents of Porta Farm were driven from their homes clearly showed the result. “You can see the square black holes on the map,” says Lavers. “They are buildings whose roofs have been removed, probably through the use of fire.”

Although the information gathered often needs to be ‘ground-truthed’ — combined with eyewitness reports — the resulting evidence is still strong. “We’re a scientific organization, so we just produce our analysis then hand it over to advocacy organizations to use for their causes,’” says Wolfinbarger. “But it adds a lot of legitimacy to their reports, and our imagery is currently being used in three cases before the international courts.”

Even the lower-resolution imagery found on sites such as Google Earth can have a powerful effect. “An image is very persuasive and easy to understand,” says Dr. Jo Woodman, a researcher at Survival who worked on the campaign against the construction of Vedanta’s aluminum mine on a mountain in the Niyamgiri Hills in eastern India that’s sacred to the Dongria Kondh. The company claimed that it had taken Dongria leaders to the nearby Panchpatmali mine and that they were “amazed to see the positive impact of bauxite mining.”

“It was ridiculous,” says Woodman. “But we were able to show shareholders satellite images of the destruction caused by the existing mine and say, ‘How likely do you think it is that the Dongria Kondh said that this was something they wanted on their mountain, too?’ It helped people realize that what we’re talking about is real. And by helping to persuade high-profile shareholders such as the Church of England to sell their shares, I think it definitely helped raise the profile of the case and save the mountain.”

Information Voids
Today, there are few corners of the globe that are beyond the reach of the satellite’s eye. “It makes the world a safer place,” says Brender. “Satellite imagery acts as a visual truth serum and forces people to react.”

However, Bromley adds a note of caution, pointing out that although there are no longer any ‘information voids’ around the globe that can be used as ‘a hiding place for repressive governments’, in order to make the world a better place, that information still has to be acted upon, or it will simply be “highlighting the impunity with which they can act.”

Editor’s Note
This article is courtesy of Geographical magazine and was originally published at
http://www.geographical.co.uk in January of 2011.

Smoke Alarm
In an ideal world, satellite imagery could prevent human rights or environmental abuses from even occurring by sounding an alarm if anything untoward was spotted taking place. There’s no all-seeing eye, as yet, but Brazil does already use a satellite-image linked program to warn Amazon land managers if unexpected deforestation is occurring in certain areas. Lars Bromley, a geographer and geospatial information expert based at the UN, is working on a computer program that will detect conflict by using satellite data of fire occurrence.

While he was carrying out his graduate research, Bromley discovered that on-the-ground fire levels in Darfur increased dramatically during the worst periods of violence to civilians, and were far higher than that which would usually be occurring at that time of year due to farming. He realized that the presence of fire was a clear indicator of homes and land being maliciously burned, and he was proved right when the UN later spotted the same pattern during conflict in Nairobi and Georgia.

“The presence of fire doesn’t always correlate with levels of civil strife,” says Bromley, “but in my experience, if you’re seeing a lot of fire, then the fighting is very likely to be having a heavy impact on civilians.”

He’s now attempting to create a model that will automatically notify the UN of fire-accompanied conflict events. “It’s a fantastic mathematical and technological challenge,” says Bromley, but he acknowledges the need to be pragmatic. “Can I build a million-dollar system to detect conflict on the ground automatically? Yes, I probably can. But would it be wiser and more cost-effective to simply pay attention to what local people are saying in these areas? Yes, it probably is. And if it’s more cost-effective to verify local reports of conflict using satellite imagery then we’ll do that, and worry less about space-based conflict-detection systems.”

Clearing The Air
Astrophysicist Chris Bishop, who works at the University of Plymouth with Dr. Chris Lavers, usually spends his time looking at star births in images produced by a state-of-the-art telescope based in Hawaii, but the techniques he uses to compare images of stellar newborns can also be applied to satellite imagery of the Earth. “In order to work out whether anything has changed between before and after satellite images, you need to subtract one image from the other,” says Bishop. “If nothing has changed, the resulting image will be completely blank, but if something has changed, it should immediately be revealed.”

It sounds simple, but the problem with looking at both stars and the Earth from a long way away is that the Earth’s atmosphere often gets in the way. Between the time of the first image being taken and the second image being taken, the conditions in the atmosphere often change, making it a lot more difficult to compare the images,” says Bishop. “The astronomy community uses an experimental program called ISIS to balance out the blurring caused by the atmosphere so that two images can be compared,” he continues. “It had never been used in a non-astronomical context before, but Chris and I are now using it to compare satellite images of the Earth.

“It makes a real difference — the image resolution is improved by about 10 to 15 percent,. You can spot something such as a damaged hut in Sudan that might previously have been invisible.”