Add SAR idea

README.md

@@ -11,3 +11,7 @@ From a photograph containing topographic features, can the location and view ang
 ## Electrical network frequency analysis
 
 Create an open source package for chrono-locating a audio/video source by matching electrical network frequency variations (from low frequency hums in source audio) with recorded variations in a grid frequency database (i.e. https://osf.io/m43tg/). This is theoretically possible (many IEEE articles about it) and reportedly in use by state-level justice entities, but is it practical for the OSINT hobbyist? To our knowledge, no one has publicly developed a public, non-academic proof-of-concept of this.
+
+## Complex SAR imagery
+
+Synthetic aperture radar imagery (as captured by, e.g., Sentinel-1) has certain advantages over optical imaging for open source investigation. It is unaffected by cloud cover and can even be used to detect radar installations, as has been previously documented. An additional advantage, little explored in the open source investigation community, is that these images are complex, that is, they contain both magnitude and phase information. While difficult to work with for several reasons (not accessible in Google Earth Engine, requires "unwrapping", etc.), it has some useful applications for computing topography or topographic changes. It is often used in academic research to visualize crust deformations following an earthquake or long-term land subsidence in agricultural areas. Could this phase data also be used for open source investigations, for example to see deforestation or bombing impacts?