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LIDAR Map Shows Height of Earth's Forests

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  • First post (Score:5, Funny)

    by Anonymous Coward on Monday February 20, 2012 @08:17PM (#39105387)

    http://xkcd.com/1019/

    • "0 Full 0 Abbreviated 1 Hidden". u'll not get paid.
    • What is this "peer consensus" thing of which you speak?

      • by Anonymous Coward

        What is this "peer consensus" thing of which you speak?

        This is slashdot. You know, it thing where lots of people get together and decide as a group the thing they want to believe in, which is usually factually wrong, unsubstantiated in any way, or just flat out stupid. Its more commonly known as a cluster fuck.

  • by Anonymous Coward

    Shooting forests with lasers from space? I think we now know who is responsible for both the recent crop of large scale forest fires and global warming as a whole.

  • Google Earth (Score:5, Interesting)

    by Cinnaman (954100) on Monday February 20, 2012 @08:35PM (#39105523)

    When can we get height data with good enough resolution to show individual trees and buildings?

    • Re:Google Earth (Score:5, Informative)

      by Anonymous Coward on Monday February 20, 2012 @08:50PM (#39105635)

      You need 1m posting or better lidar data to get the individual trees and buildings. For the State of North Carolina, which was one of the first states with complete lidar coverage ( for floodplain mapping purposes), 1/3 of the state was flown at -12m posting distance and 2/3 was flown at 5m posting distance , Even at this relatively coarse resolution, there are about 26 billion x,y,z points for the State data set. You can process this as a single file using GRASS GIS or LAStools in a couple of days on a 2Ghz cpu ( single threaded). Consider that 1 m posting gives you 25 times the data points as 5 m posting and pretty soon you are talking about interesting data set sizes.
       

      • by sgtstein (1219216)
        Oh, so THAT is why our GIS analysts are wanting a new 100TB Backblaze storage pod and dedicated servers. Thanks for the info!
        • by Anonymous Coward

          You're not a very good geek. There doesn't have to be a reason to get new hardware like that...

      • by xded (1046894)

        From TFA:

        The researchers augmented the ICESat data with other types of data to compensate for the sparse lidar data, the effects of topography and cloud cover. These included estimates of the percentage of global tree cover from NASA's Moderate Resolution Imaging Spectroradiometer on NASA's Terra satellite, elevation data from NASA's Shuttle Radar Topography Mission, and temperature and precipitation maps from NASA's Tropical Rainfall Measuring Mission and the WorldClim database.

        From a video with a Google Earth overlay [nasa.gov] you can find on NASA's ICESat mission website, the points from a single pass look more like 100 m apart.

        • by Anonymous Coward

          Very close, MODIS (Terra) resolution is ~90m if I remember right. SRTM is 3 arc-sec (~90m latitude) 60N-60S but 1" (~30m latitude, same as LANDSAT) over the USA. In reality it's only very reliable at 90m though.

          (props to Prof Mitasova @ NCSU!)

  • by Kittenman (971447) on Monday February 20, 2012 @09:01PM (#39105717)
    My whole country seems to have been missed (you insensitive clods!). And we're pretty much all forest down here....
  • Interesting (Score:5, Informative)

    by retroworks (652802) on Monday February 20, 2012 @09:13PM (#39105797) Homepage Journal
    I'm from the Ozarks, and was shocked to learn as an adult that virtually the whole area of Arkansas-Missouri-Tennessee etc. was clear cut 100 years ago, and that there is more growth now than my grandparents had around them. But in Africa, saw the opposite, the clearing of forests at a frightening pace. If this can show us year-to-year how the forests are shrinking or growing, we may find out that the loss of carbon consumers is as important as the growth of carbon emitters.
    • This isn't the first or only way to measure/visualize forestation. Visible light and infrared imaging have been used for this purpose for decades now (and spectrography can tell us stuff like what species we're looking at), so we already have a pretty good idea of how many carbon consumers are lost over time.

  • What are laser-wielding sharks doing in space? Thank goodness they're just taking orders from NASA!

  • With all this remote sensing and especially with the now (more) common use of ACTIVE sensors, is there any way the average, non-James Bond citizen can know what exactly he's being scanned with?

    Sort of like a radar detector for the 21st century; some sort of gadget that would tell you when some space-borne laser is strobing you or some military radar is illuminating you or you're walking through someone's microwave beam spillover? Or is that way beyond being practical now?

    It might be interesting to know whi

    • by tftp (111690)

      With all this remote sensing and especially with the now (more) common use of ACTIVE sensors, is there any way the average, non-James Bond citizen can know what exactly he's being scanned with?

      No, the average citizen cannot know that. The reason is that the emitter is usually not constrained by cost, and emitters exist only in small quantities. For example, that TSA scanner van may exist in quantity one, but the whole population of the USA may be required to be on the lookout for it.

      Those emitters also

  • I said I'd like to try the train up from Helsinki. They said, "Why bother? All you'll see is trees, just shorter trees as you go north."

    And, from the low-resolution map at least, they seem to be right.

  • This data would be useful for flight simulator makers such as flightsim.org and orbiter!
  • ... as to whether the trees in this study are just the right height?
  • It's pretty much my favorite optical remote sensing technology.

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