Anonymous ID: 64d1f3 Nov. 18, 2023, 6:14 a.m. No.19936470   🗄️.is đź”—kun   >>6474 >>6620 >>6947

A New Tool Allows Researchers to Track Damage in Gaza

November 15, 2023

As the Israel Defense Forces (IDF) continue to bomb the Gaza Strip, many researchers are attempting to track and quantify the damage to the territory’s buildings, infrastructure and the displacement of the local population.

A new tool, originally developed to estimate damage in Ukraine, has now been adapted and applied to Gaza. The tool can estimate the number of damaged buildings and the pre-war population in a given area within the Gaza Strip.

The tool has already been used by a number of media outlets, but it is freely available for anyone to use and we have outlined its key features below.

The coloured overlay on this map is a damage proxy map indicating the probability of a significant change occurring at particular locations since October 10, 2023. Users can click the “draw polygon” button to draw an area of interest on the map — for example, a particular neighbourhood.

To understand how the tool works, let’s look at the neighbourhood of Izbat Beit Hanoun, which sustained heavy damage visible in these high-resolution, before-and-after satellite images from Planet:

The row of apartment complexes in the north of the neighbourhood near the road has been razed. Lower-density areas in the centre and northeast of the neighbourhood have also sustained heavy damage. Airstrikes have also destroyed several of the apartment complexes in the southwest.

Below is the damage probability map generated by the tool, highlighting many of these areas:

Drawing a box over this neighbourhood allows us to roughly quantify the number of buildings – and people- affected by the destruction.

In the neighbourhood of Izbat Beit Hanoun, the tool estimates that there are 321-425 damaged buildings (73 — 97%), displayed with colours above. The tool also estimates that in the area of interest there was a pre-war population of 7,453, of which 4756 – 6304 lived in areas that are now likely to be damaged.

How it Works

Synthetic Aperture Radar (SAR) imagery has been used extensively in academic studies of building damage, and by groups like NASA following the 2020 explosion at the port of Beirut. NASA explains the use of SAR for building damage detection as follows: “SAR instruments send pulses of microwaves toward Earth’s surface and listen for the reflections of those waves. The radar waves can penetrate cloud cover, vegetation, and the dark of night to detect changes that might not show up in visible light imagery. […] When buildings have been damaged or toppled, the amplitude and phase of radar wave reflections changes in those areas and indicate to the satellite that something on the ground has changed.”

The application above detects damaged areas by measuring the change in the intensity of the radar waves reflected back to the Sentinel-1 satellite before and after October 10, 2023, adjusted for how noisy the signal is in both periods. A more detailed explanation of the algorithm (which was peer-reviewed for a conference) is available here, and a walkthrough (including code) applied to the 2020 Beirut explosion is available here.

more at: https://www.bellingcat.com/resources/2023/11/15/a-new-tool-allows-researchers-to-track-damage-in-gaza/