![]() ![]() In the U.S., the USDA’s National Agricultural Imagery Program (NAIP) captures 1m/pixel or better imagery for the entire contiguous United States once every other year. Make sure you familiarize yourself with the data before downloading a lot of it!įor high-resolution aerial imagery, your options are much more limited. A warning: these are very large files and the imagery itself is lower resolution than what you might expect to see on a typical web map. MODIS (NASA’s satellite constellation which images the earth every 1-2 days)ĭata from all three of these satellite constellations can be downloaded for free from either Earth on AWS or Google’s Earth Engine Catalog.Landsat 8 (the USGS’s satellite which images the earth once every 16 days).Sentinel-2 (the European Space Agency’s constellation of satellites imaging the entire landmass of the earth once every five days).Here’s where things get interesting-we’ve written previously about the explosion of freely available, openly licensed, and constantly updating satellite imagery in our blog post, An Introduction to Satellite Imagery and Machine Learning. For larger-area basemaps, satellite imagery providers make more sense: and Australia and has a very simple user interface available through any web browser. For high-resolution aerial imagery, NearMap orthographics provide great coverage in the U.S. Rather than license imagery from Google that they’re, in turn, licensing from imagery providers, it usually makes more sense to go directly to the source. Google’s Maps API is notoriously stingy in this regard, with its terms of service even limiting your right to display content derived from Google imagery on a map that isn’t also provided by Google. tracing building footprints or other cartographic features), you should consider a paid option that allows for derivative works to be produced. If you’re considering deriving a commercial product from the imagery you’re browsing (e.g. ![]() Some other great sources of non-commercial, non-downloadable imagery are: Mike Wall is the author of " Out There " (Grand Central Publishing, 2018 illustrated by Karl Tate), a book about the search for alien life. And none of them pose a danger for the foreseeable future. For example, NASA and its partners have found more than 95% of the asteroids out there at least 0.6 miles (1 km) wide that are thought to come within 30 million miles (50 million km) of Earth at some point. NASA opened its Planetary Defense Coordination Office a few years after the Chelyabinsk event, and astronomers and researchers around the world have joined the Earth-protection fight.Īs a result, scientists are getting a better and better handle on the NEO population. ![]() The incident highlighted the importance of better understanding the NEO population, astronomers said, stressing that it's only a matter of time before a truly dangerous asteroid lines Earth up in its crosshairs. 15, 2013, a roughly 65-foot-wide (20 m) space rock exploded without warning over the Russian city of Chelyabinsk, shattering thousands of windows and causing minor injuries on the ground (mostly from flying shards of broken glass). How humanity could deflect a giant killer asteroidĢ005 YY128's close approach comes on a fateful day - the 10th anniversary of the Chelyabinsk airburst. How big is the asteroid threat, really? Potentially hazardous asteroids (images) "Smaller NEOs in the 140-meter to 1-km size range could cause regional up to continental devastation, potentially killing hundreds of millions."Īgain, however, do not be alarmed: 2005 YY128 poses no danger on this pass. "The largest near-Earth asteroids (> 1 km diameter) have the potential to cause geologic and climate effects on a global scale, disrupting human civilization and perhaps even resulting in extinction of the species," the Sweden-based nonprofit Global Challenges Foundation wrote of the asteroid-impact threat. If 2005 YY128 did slam into Earth, it would do serious damage, no matter which part of its stated size range the asteroid actually occupies. So 0.05 AU is roughly 4.6 million miles, or 7.4 million km.) (One AU is the average Earth-sun distance - about 93 million miles, or 150 million km. The best astronomers can give us is a diameter range - somewhere between 1,903 feet (580 meters) and 4,265 feet (1.3 km), according to EarthSky.Ģ005 YY128 therefore qualifies as a potentially hazardous asteroid (PHA), a designation given to space rocks at least 460 feet (140 m) wide whose orbits take them within 0.05 astronomical units (AU) of our planet. Their observations, however, haven't nailed down 2005 YY128's size. ![]()
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