JUDY WOODRUFF: There were reports of shelling and clashes in another northern city today. Those were in Aleppo, Syria's largest city and commercial center.
Assad's forces and the rebels have been fighting there for the past several weeks. Now there's a new tool in the arsenal, not a deadly one, but rather one that provides key information.
Margaret Warner has our story.
MARGARET WARNER: The fighting in Aleppo is now being monitored by a human rights organization using commercially available satellite imaging.
Amnesty International recently commissioned DigitalGlobe, which operates three private satellites out of this control room in Denver, to take images of Aleppo and the surrounding area. It's part of a small but growing trend over the past decade.
To document suspected human rights abuses on the ground in places like Sudan, nonprofits are buying high-resolution satellite imagery. Now this same "eye in the sky" technology is being employed to document the Syria conflict.
To explain and analyze this satellite imaging project in Syria, we turn to Scott Edwards, managing director for crisis prevention and response at Amnesty International USA, and Susan Wolfinbarger, the geospatial analyst with the American Association for the Advancement of Science. She's with its Geospatial Technologies and Human Rights program.
Welcome to you both.
Scott Edwards, beginning with you, what are you trying to accomplish here? What are you looking for?
SCOTT EDWARDS, Amnesty International USA: We had heard all of these reports in Syrian media and elsewhere about a forthcoming decisive battle.
And as we have done in the past and as we have documented in the past, we often have to deal essentially with the fog of war when you're dealing with civil conflict situations.
And something that is incredibly valuable when you have high-risk security environments, where it's difficult to get researchers on the ground to corroborate reports of human rights violations, is to rely on essentially ways to circumvent those information blackouts, such as satellite imagery.
So, in the case of Aleppo, we were very curious exactly what the state of play was with regard to military hardware, positions of particular units, pro-Assad units and other units, both sides, and to essentially take a baseline of what the city looked like in order to assess risk.
MARGARET WARNER: Now, both sides have actually been accused of human rights violations in this conflict, the Syrian military much more than the rebels. What are you looking for in that regard?
SCOTT EDWARDS: We're looking to ensure that all actors take all necessary measures to protect civilians, to minimize civilian casualties, and noncombatants, and that includes those who have been captured on either side who are no longer taking part in hostilities.
MARGARET WARNER: Well, let's take a look at the satellite images that you released this week.
And, Susan Wolfinbarger, I would like you to tell us what we're seeing. The first one actually is not from Aleppo, but from this town called Anadan, which is about 10 miles outside of Aleppo, and in fact, already is reported to be almost cleared of all of its inhabitants because it's already withstood an assault.
What do you see in this shot?
SUSAN WOLFINBARGER, American Association for the Advancement of Science: It's from July 31.
And in this image, you can see in the central and southern part is the actual town of Anadan. And then the yellow dots that you see surrounding the city are the probable impact craters that were identified by DigitalGlobe in the analysis that they conducted.
MARGARET WARNER: So, by artillery, impact craters, you're talking about the yellow dots.
SUSAN WOLFINBARGER: Yes.
MARGARET WARNER: Then we have a sort of close-up here. How do you know these black areas are artillery impact craters?
SUSAN WOLFINBARGER: This is a subset of the larger image.
And you can see a variety of these black dots that are located across the image. Each of these areas are about three to four meters in diameters. And I have done previous...
MARGARET WARNER: Three to four meters?
SUSAN WOLFINBARGER: Yes.
MARGARET WARNER: So like nine feet, 10 feet, 12 feet.
SUSAN WOLFINBARGER: Yes. They can be quite large.
I have done previous analysis that looks at impact craters in other conflict situations. And so, these are very consistent with the type of craters that we have seen in other situations. And the large number of them can also help us to conclude that these aren't something that's occurring due to chance.
There is room for interpretation on the part of the analysts, but we can feel confident saying that these are impact craters from mortars.
MARGARET WARNER: So, Scott, what analysis or conclusion did Amnesty draw from these Anadan photos?
SCOTT EDWARDS: There's great risk to civilians in Aleppo and in Anadan and the surrounding areas.
The fact that the analysts were able to identify over 600 probable impact craters of course, makes it very clear that heavy weaponry is very much present in and around Syria's largest city.
MARGARET WARNER: Now, here we have Aleppo, where the -- the assault is gathering, but hasn't fully exploded yet. What do you see here in this very wide shot of Aleppo?
SUSAN WOLFINBARGER: In DigitalGlobe's analysis, they have already begun to identify some clustering of different types of military installations, artillery, things of that nature.
MARGARET WARNER: So, like, the little red ones are military activity or...
SUSAN WOLFINBARGER: And the orange are roadblocks that they have identified. But really you can tell more from the second image.
You can see in this image collected on July 23 a number of different roadblocks using vehicles that you would find just out in the city, so buses, trucks parked horizontally across the roadways, instead of alongside the roadways. And, in addition, you can also see there is one that is over on the left side of the image, that there's actually a large black cloud of smoke that is coming from it, so it's likely been set on fire.
MARGARET WARNER: So, Scott Edwards, what do these photos say to you?
SCOTT EDWARDS: Our aim here is twofold.
One is to do a baseline assessment of where we're likely to see or where it's possible that we will see violations of humanitarian law and the rules of war should the conflict escalate in Aleppo.
The second is to make it very clear to actors on the ground in fact that we are watching, and it's perfectly conceivable that we can reconstruct which units are operating where when certain large-scale human rights violations occur.
And that should give pause to those actors on the ground who might carry out illegal orders.
MARGARET WARNER: And there are limitations to this, right?
SUSAN WOLFINBARGER: You can't, for example, see inside of buildings. And the resolution of the satellite prevents you from seeing very small interpersonal violence.
SCOTT EDWARDS: And what I would also say is satellite imagery and imaging is just one way that Amnesty works to document grave human rights violations.
But we have already put out a lot of researchers on the ground, and that will certainly continue. And we will use every resource we can and every technological advancement we can to build the case.
MARGARET WARNER: Well, Scott Edwards from Amnesty International USA, and Susan Wolfinbarger, thank you so much.
SUSAN WOLFINBARGER: Thank you.
GWEN IFILL: You can take a closer look at the satellite images we just showed you on our website.