Landsat 8 Data Now Available | Hacker News Reader

Landsat 8 Data Now Available

landsat.usgs.gov

79 pointsmxfh19 comments

This is such an amazing dataset. I really like the cloudless map tiles that Mapbox are producing. http://www.mapbox.com/blog/cloudless-atlas-with-landsat/

Does anyone know if there is a way to access the image archive in a more direct way than through one of the web interfaces ? FTP or WMS ?

I don't think so, no FTP. I always wondered why that is... As countless interns spent countless hours making orders and clicking the download links... And I don't think WMS can be direct, it's multiband tifs in it's own path/row :)

Scenes are processed as you request them. Once they are processed they are available for immediate download by anyone.

Check out the FAQs on the landsat site: http://landsat.usgs.gov/search_and_order_Landsat_scenes.php

Also check out WELD. I don't think it has Landsat 8 data yet but it may meet your needs: http://landsat.usgs.gov/WELD.php

I wonder how this will affect the Maps data that Google/Apple/Microsoft has.

It probably won't, because its not very high resolution. Landsat is more about the spectrum coverage, 8 bands including infrared, and temporal coverage, a pass every 16 days, since 1984. This is useful for scientific studies.

Google/Apple/Microsoft buy their data from private satellites that at a much higher resolution and in plain visible RGB, and they only need a single cloud-free composite from any time, which is why some of the Google imagery doesn't have new buildings.

Google does store and provide Landsat and MODIS datasets in their Google(c)(tm) Maps Engine, and Earth Engine, for science related applications.

    > Google/Apple/Microsoft buy their data from private satellites

The Google coverage people are most familiar with (i.e. major cities) is not from private satellites, but private aerial surveys.

Maybe in the US and other select regions, certainly not globally though.

Moscow, Russia: https://maps.google.com/maps?q=moscow&hl=en&ll=55.75...

Tokyo, Japan: https://www.google.com/maps?q=tokyo&ll=35.689143,139.695...

Tunis, Tunisia: https://www.google.com/maps?q=Tunis,+Tunisia&ie=UTF8&...

Monrovia, Liberia: https://www.google.com/maps?q=monrovia,+liberia&hl=en...

Niue (a tiny island nation 1,500 miles off the coast of New Zealand): https://www.google.com/maps?q=niue&hl=en&ll=-19.0103...

So yeah, I think it's pretty global.

everything you posted (except Tokyo) is satellite imagery only as far as i can see - so where is your point?

Really? In Niue you can see the lines on the basketball court. The best commercial satellite imagery I know if is about .5 meters (20 inches).

Now that I look at it though, the Moscow one is pretty fuzzy...

"Detect" and "resolve" are two different things when it comes to imaging.

You can detect the lines on the court because they're bright white on dark background. However, you can't tell if it's one line or two parallel white lines less than ~1m apart.

In other words, you can't accurately measure the width of an object less than the resolution of the imagery, even if you can tell that it's present.

The Niue imagery is ~1m resolution. If you hunt around a bit, you can find a few cars. Note that you can measure their width, but it's difficult to do.

So 5 cities must mean the same as 200 countries now?

Also except Tokyo these are all extremely low-res at my high-speed end, hinting towards Satellite imagery.

That used to be the case, but these days it is mostly satellite data.

The newer civilian satellites (a lot of them are dual-purpose military/civilian) are capable of resolutions below 1m. ~2m resolution satellite imagery has been available for over a decade now (e.g. the IKONOS and recent SPOT satellites).

I think (?) most of Google's imagery currently comes from the GeoEye-1 satellite, which they partially funded.

Just to make to make what I'm saying more clear:

I'm certainly not disagreeing that the highest zoom levels in major cities are aerial photographs. The city-block level imagery available globally is from satellite, though.

For example, compare this (probably satellite, little building lean and ~1m resolution): http://goo.gl/maps/mJadH

To this (definitely aerial, lots of "lean" and ~10-20cm resolution): http://goo.gl/maps/WYnvE

How can I see just the infrared?

OK, so what kinds of things can you do with this data?

The frequency and depth of archive combined with non-visible spectrum records mean Landsat is great for monitoring changes over time over large areas. One of the best uses I"ve seen is monitoring forest clearing and burning in the Amazon.

Also, the long record of using the same spectrum bands within the Landsat program (going back to the 70s) simplifies measuring changes over time. This is a huge asset.

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