3 ms·
Chinese satellite calibration marker: https://earthengine.google.com/timelapse#v=40.44355,93.719,11.573,latLng&t=1.87&ps=50&bt=19840101&et=20181231&startDwell=0
by whywhywhywhy 6y ago
Chinese satellite calibration marker: https://earthengine.google.com/timelapse#v=40.44355,93.719,11.573,latLng&t=1.87&ps=50&bt=19840101&et=20181231&startDwell=0&endDwell=0 https://earthengine.google.com/timelapse#v=40.44355,93.719,1...
Three Gorges Dam: https://earthengine.google.com/timelapse#v=30.89428,110.73344,9.533,latLng&t=0.99&ps=50&bt=19840101&et=20181231&startDwell=0&endDwell=0 https://earthengine.google.com/timelapse#v=30.89428,110.7334...
- trishmapow2 6y agoMore information on satellite calibration markers for those curious like me: https://www.livescience.com/17052-mysterious-symbols-china-desert-spy-satellite-targets-expert.html https://www.livescience.com/17052-mysterious-symbols-china-d... US version: https://en.m.wikipedia.org/wiki/Corona_Satellite_Calibration_Targets https://en.m.wikipedia.org/wiki/Corona_Satellite_Calibration...
- londons_explore 6y agoThe US marker makes sense - it allows checking all alignment angles, focus, scale, and various spacial frequency response parameters to be measured. All in perhaps the simplest possible shape. The Chinese one on the other hand, isn't so useful for any of that. All the lines are the same thickness, and there are no smaller features for fine calibration or measurements. For just calibration, it's far bigger and more complex than necessary.