Thread by @ai6yrham

Since people are asking, how to geolocate a #hiker given only a general location and a grainy photo of their legs hanging off a cliff (thread) 1/x

1. Identify the general area (if available) of where the hiker was known to be. In this case, the location was near Mt. Waterman (a well known area in the Angeles Crest, popular with hikers). 2/x

2. If someone is lost along the Angeles Crest (if you keep tabs on the posts of @SEBLASD they post regularly on rescues), you find they are either NORTH of the Angeles Crest Highway or SOUTH of the Angeles Crest Freeway. How do we figure out which one here? 3/x

This is important, because if a hiker is moving, they're likely moving downhill (not uphill)... so they'll either keep drifting north or south into the drainages or get hung up on a cliff/etc. 4/x

Here's where recent satellite data is important. The EU has the Sentinel-2 satellite (via @sentinel_hub EO Browser) which shows high resolution views of almost every place on earth, captured every few days. VERY important to see what something looks like NOW, not archived. 5/x

Google Earth has archived data, so it's tough to use the photo of the legs for any idea of where the photo was taken. Sentinel-2, on the other hand, shows where the vegetation roughly matches the background of the legs (green in the bottom but burnt/dry above). 6/x

Zooming in South of Mt. Waterman, it's suddenly striking how similar this area looks to the photo background. But it's not at the same angle. 7/x

Fortunately, @sentinel_hub recently added 3D visualization tools (you can also download the image to Google Earth as a JPG/KMZ if you wanted, but more steps). If you use those 3D tools and move around... you get this. 8/x

Hey, you say, I think I found what the lost hiker is looking at! Which leads to... 9/

You then go back into Google Earth 3D, which has some measurement tools, drawing tools, etc. which you can't get in EO Browser. Looks like this location. But are we sure? 10/x

We really need the time of day to be sure. Thanks to a few tips (@engineco16 @OSV227Hex), figured out more info in the Nixle (but not Tweet) with time of day of the photo (approx). 11/x

Using the time/date feature of Google Earth (desktop).. bingo. Uncanny match (enough to convince SAR folks that no, I was not a stupid armchair detective with no clue ;-) 12/x