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NASA, Japan Make ASTER Earth Data Available at No Cost

96 points by antouank 11y ago

poorUXrage 11y ago
How exactly do you download the data? I am looking at the page the article linked to and I do not see any intelligible download link, just some factoids about the craft. Is there a giant tarball I can slurp down. How big is the data set anyway?
- rhizome 11y ago
  there are two links about 3/4 the way down the article.
- hamsternipples 11y ago
  took a bit to find but here's the link: https://lpdaac.usgs.gov/data_access/data_pool https://lpdaac.usgs.gov/data_access/data_pool
buckhx 11y ago
I hadn't heard of this project before, but this sounds pretty awesome. I wonder what the fidelity is and if it could be used to fill in the height tag missing from lots of OSM buildings.
- maxerickson 11y ago
  The grid spacing is 30 meters, so probably not.
- vilhelm_s 11y ago
  Jonathan de Ferranti has a webpage reviewing different digital elevation maps (http://viewfinderpanoramas.org/reviews.html#aster http://viewfinderpanoramas.org/reviews.html#aster ). It sounds like he was not super impressed with the ASTER height data (the review is from 2011): > Despite the nominal 1" resolution, the true resolution is lower than 3" (downsampled from 1") SRTM data, and there are very many pits, bumps and mole runs. So far the tallest spike that I have found is 3,844 metres, at N 60�43' E 22�02', in south west Finland, and the deepest pit is about 3,000 metres, in tile N27E088, containing cells below 5,300m close to where Kangchenjunga's main summit ridge should rise to 8586m. Generally, artifacts are visible in almost all areas of low relief. Coastlines are not at all accurate; lakes have not been flattened and are particularly badly affected by artifacts. Major errors can be found in most areas of very high relief, But in between, some areas of medium to high relief have been well done and are almost artifact free. My early impression is that, for areas where topographic coverage is poor, these data could be separated out for use to improve DEM data, including both mountain and desert voidfill data, on this and other sites. At one time I thought it may also be possible to flatten the low relief artifacts to provide data that will improve coverage of the plains of North Eurasia, but after further consideration I doubt that this will be possible.
loudmax 11y ago
I work with Terra's ground based flight crew. I don't know much about ASTER specifically, but most of the instruments on Terra have a very wide field of cover and gather light in bands beyond of our spectrum of vision. The data primarily of interest to climatologists and scientists. You won't be able to pick out cars parked on our street in these images. Historical and current data from some of Terra's other instruments is available on Worldview here: https://worldview.earthdata.nasa.gov/ https://worldview.earthdata.nasa.gov/

96 points by antouank 11y ago

How exactly do you download the data? I am looking at the page the article linked to and I do not see any intelligible download link, just some factoids about the craft. Is there a giant tarball I can slurp down. How big is the data set anyway?

rhizome 11y ago
there are two links about 3/4 the way down the article.
hamsternipples 11y ago
took a bit to find but here's the link: https://lpdaac.usgs.gov/data_access/data_pool https://lpdaac.usgs.gov/data_access/data_pool

buckhx 11y ago

I hadn't heard of this project before, but this sounds pretty awesome. I wonder what the fidelity is and if it could be used to fill in the height tag missing from lots of OSM buildings.

maxerickson 11y ago
The grid spacing is 30 meters, so probably not.
vilhelm_s 11y ago
Jonathan de Ferranti has a webpage reviewing different digital elevation maps (http://viewfinderpanoramas.org/reviews.html#aster http://viewfinderpanoramas.org/reviews.html#aster ). It sounds like he was not super impressed with the ASTER height data (the review is from 2011): > Despite the nominal 1" resolution, the true resolution is lower than 3" (downsampled from 1") SRTM data, and there are very many pits, bumps and mole runs. So far the tallest spike that I have found is 3,844 metres, at N 60�43' E 22�02', in south west Finland, and the deepest pit is about 3,000 metres, in tile N27E088, containing cells below 5,300m close to where Kangchenjunga's main summit ridge should rise to 8586m. Generally, artifacts are visible in almost all areas of low relief. Coastlines are not at all accurate; lakes have not been flattened and are particularly badly affected by artifacts. Major errors can be found in most areas of very high relief, But in between, some areas of medium to high relief have been well done and are almost artifact free. My early impression is that, for areas where topographic coverage is poor, these data could be separated out for use to improve DEM data, including both mountain and desert voidfill data, on this and other sites. At one time I thought it may also be possible to flatten the low relief artifacts to provide data that will improve coverage of the plains of North Eurasia, but after further consideration I doubt that this will be possible.

loudmax 11y ago

I work with Terra's ground based flight crew. I don't know much about ASTER specifically, but most of the instruments on Terra have a very wide field of cover and gather light in bands beyond of our spectrum of vision. The data primarily of interest to climatologists and scientists. You won't be able to pick out cars parked on our street in these images. Historical and current data from some of Terra's other instruments is available on Worldview here: https://worldview.earthdata.nasa.gov/ https://worldview.earthdata.nasa.gov/