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Space Science

Shuttle Radar Topography Mission Data 97

SubtleNuance writes: "This story on Canada.com describes the mission and results of NASA's recent flight to map Earth. The Shuttle trip has provided the most detailed 3D photos of Earth ever released." Some of the images are just astounding. Too bad most of the data isn't available yet.
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Shuttle Radar Topography Mission Data

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  • Original Caption Released with Image:

    This dramatic view looks west along the Cucharas River Canyon in Colorado toward the 4,152 meter (13,623 ft) high Spanish Peaks, in the foothills of the Sangre De Cristo Mountains. The Peaks are the remnants of a 20-million year old volcano. Rising 2,100 meters (7,000 ft) above the plains to the east, these igneous rock formations with intrusions of eroded sedimentary rock historically served as guiding landmarks for travelers on the Mountain Branch of the Santa Fe Trail.

    The above paragraph is the best possible argument for NASA to hire more earth scientists when they do earth science, such as the Shuttle Radar Topography Mission. They casually mention a whacking big mystery--sedimentary rocks seen intruding igneous rocks--and then leave us hanging. How did those sedimentary rocks do that?

    Usually, sediments stack themselves on top of what's already there, instead of sticking themselves into the existing rock in an intrusive manner. Sediment becomes a candidate for rockhood when the force moving it along goes away. The wind falls, the streams slow down, the ocean dries up. Mineral grains lie down and rise no more.

    So if these sediments really got a volcano to bend over and be intruded, they were motivated by an unknown geologic force. Was it lust? Lust between consenting rock bodies has not been found to leave a distinguishable trace. But rock bodies can radiate sex appeal. French trappers saw mountains and canyons as giant erotic apparitions, and gave their lovesick hallucinations names which remain French because it won't do to translate them on public road signs. Perhaps these sediments saw the firm, youthful Spanish Peaks in the same rosy light--they look pretty good in rosy light, I can tell you--and before you knew it, innocence had become experienced. These unique sedimentary rocks deserve further study, for which I offer my services to NASA.

    maqbroom

    geologist

    Note: They're talking about the remarkable dikes which tower over Colorado state highway 12 south of La Veta. Although these rocks look just like sedimentary rocks (vertical sheets and stacks of sheets), they're of igneous origin. As the Spanish Peaks volcano grew in size 20 million years ago, the buoyant magma body below was covered by cubic miles of rock. The magma had not changed its elevation relative to sea level, but the deeper burial now made it more buoyant than when it first arrived near the surface. It was like a beach ball forced under water--the magma would return to its level, rising into the volcanic pile. The volcano, made of loose material and lava flows, cracked in a star pattern--as big, composite round things do when something else big and roundish intrudes it from below. Molten rock followed the cracks, freezing into vertical sheets. That's the impressive rock walls you see over the highway. Worth a side trip.

    For a topographic map, go to http://www.topozone.com and enter La Veta, CO on their "Get a Map" page. Choose the "large" map format, and click on the arrow pointing south to see the highway route around the Spanish Peaks.

  • by Zalgon 26 McGee ( 101431 ) on Friday August 03, 2001 @07:37PM (#2160553)
    Yet another reason to contact your congressman: ensure they vote for NASA appropriations.

    They aren't perfect, and more support for private enterprise in space is needed, but NASA is worthy of support.

  • With maps like this you could do some very very real full scale simulations of war.

    Perhaps the brass might see that all war is futile.
    • or we can import it certain games to make bombing runs over xyz. I got to admit, the view of Tokyo was way cool.
      ONEPOINT
    • Re:Amazing! (Score:2, Interesting)

      by NullPointer ( 6898 )
      With maps like this you could do some very very real full scale simulations of war.

      Actually, DOD did just that when US troops were sent to Bosnia. I was working on the commercial development of IFSAR at the time and got to see some of the results. The AirForce did some pretty cool virtual terrain demos for bomb-run training. Looks like TEC still has some images out there: http://www.tec.army.mil/ctis/ctis_tec/ifsare.html
    • The U.S. Department of Defense was the major sponsor of the project. The data will be used for simulations and real war. (I could say "real world" war, but "world war" has a certain meaning...)
    • Perhaps the brass might see that all war is futile.

      Good evening Professor Falken
      A strange game
      It seems the only way to win is not to play
      How about a nice game of chess?

  • Resolution? (Score:2, Insightful)

    by Sawbones ( 176430 )
    Other than "The map is going to be 100-times better than any other global map that we have," in the article there is no mention of how fine of detail the map goes into. Is it better than the 1 meter resolution of the (now defunct *sigh*) Terraserver?

    Still, cool tech.
    • You were curious what the resoultion was so I'm posting a link http://www.jpl.nasa.gov/srtm/datafinaldescriptions .html "The absolute horizontal accuracy (90% Circular Error) is 20 meters. The absolute vertical accuracy (90% Linear Error) is 16 meters. "
    • Re:Resolution? (Score:2, Informative)

      by NullPointer ( 6898 )
      Since Landsat (the image that is overlaid on the radar data) is typically 30m, these data sets won't be any better than that. If I recall, the shuttle X-band only did 100m DEM post spacing (or maybe it was 150m) with a vertical RMS in the 20m range, er, something like that.

      There are at least two commercial terrain mapping radar systems out there that can do much better. Star3i (formerly IFSARE) is now operated by Intermap (www.intermap.ca) and does 2.5m postings (Intermap may claim it does better, but I don't believe it). And, there is a new system that is currently being calibrated and may be producing data soon. In addition to X-band, GeoSAR has a P-band capability to "see" through trees, very cool (www.geosar.com).

      • Oops, forgot to mention that JPL has something called TOPSAR that they've used for demo purposes. It is essentially the same thing as what flew on the shuttle but is mounted in a DC-8, bunches of images are here http://southport.jpl.nasa.gov/airsar/topsar/
      • Since Landsat (the image that is overlaid on the radar data) is typically 30m, these data sets won't be any better than that.

        The fact that Landsat data resolution is 30 meters (actually, it varies with sensor and satellite) is *completely* irrelevant. The satellite imagery is simply overlaid over the radar-produced topographic data for visual effect when producing fancy pictures. The topographic data can be and will be of a higher spatial resolution.

        • is *completely* irrelevant

          Certainly the DEM could have a higher spatial resolution, but the images that were referenced in the article are all 30m Landsat. I was simply pointing out (and obviously didn't do it well) that the demo data everyone was seeing in the references was no better than the lowest resolution data used to create the pretty pictures.

          However, the data products page (http://www.jpl.nasa.gov/srtm/dataproducts.html) indicates that, "the final released SRTM DEM will be at 30 meters for the U.S. and at 90 meters for the rest of the world." The SRTM interferometer may be capable of a higher resolution, but those of us in the public sector won't be seeing that data anytime soon...

    • I don't think the Terraserver was able to return 3d surveys, though.

      Dancin Santa
    • on the page http://www.jpl.nasa.gov/srtm/datatimeline.html
      you'll see the resolution stats from 30m to 1 km

      and a side note
      http://www.jpl.nasa.gov/srtm/datacoverage.html Nasa states "Land area missed: 50,000 km2 (all in US)"

      ONEPOINT
      • and a side note
        http://www.jpl.nasa.gov/srtm/datacoverage.html Nasa states "Land area missed: 50,000 km2 (all in US)"

        Thats an interesting figure. looking at the map you can see where this "missed land" is:
        http://www.jpl.nasa.gov/srtm/images/bin/srtm_covma p_hi.jpg [nasa.gov]
        Note how even the coverage everywhere else is, yet theres holes over the US. Maybe I'm paranoid but I smell a "don't scan these 6 spots" request from the [insert favorite government TLA here].
        • I think you are being paranoid, if those missed spots on the map are accurate.

          Looks like Northern Florida...west of King Harbor and Pensacola, central North/South Carolina, southern Minnesota/north Iowa, and the west Texas boarder area.

          Nothing fun there. South Central Utah, Colorado and Nevada are the sites that are suspected to be "sensative".
    • Re:Resolution? (Score:2, Insightful)

      by leeward ( 313589 )

      Terraserver, and other systems that produce resolutions on the order of 1 meter, are photographic systems. SRTM is an imaging radar system, with resolution of 20-30 meters. And the key part of the phrase in your quote is "better than any global map".

      The primary job of SRTM was to generate a uniform global topographic map. There are other radar systems, such as geosar, which can get better resolution. But that is because they are mounted on airplanes, and are therefore flying much closer to their target. But you are unlikely see a global map from geosar, or any other airborne radar, because, well, the earth is just too big to cover it all in an airplane. And just trying flying a US military imaging radar on an airplane over China! They get grumpy enough about the spy planes flying off their coast. And yet SRTM made a world wide map in a single 10 day mission (except somehow they missed Area 51 - don't know how that happened).

      And the value of a uniform map is that there are maps around from literally hundreds of data sources, but maps of two different areas, made with two different data sets, are difficult to compare accurately without a uniform baseline to compare them against. SRTM data is intended to be that baseline.

      And finally, an advantages of radar data over photographic data is that it is difficult to get accurate topographic data from optical data. Also, you are at the mercy of the weather when obtaining photo data. The radar can see through clouds just fine.

    • Though I agree with several of the other replies to your comment (that Terraserver's photos weren't nearly as cool as this set), Terraserver [msn.com] is hardly defunct. In fact, it's got a lot more functionality, now. Too bad it's brought to us by the enemy [microsoft.com].

      ::Colz Grigor

      --

  • Better link (Score:4, Informative)

    by DESADE ( 104626 ) <slashdot@NoSPam.bobwardrop.com> on Friday August 03, 2001 @07:38PM (#2160559)
    here [inlandempireonline.com]
    • Very cool site - thx, DESADE. They have a whole bunch of great in-depth sites on different news topics, like the stem cell thing.

      The topography pictures are beautiful. I'm wondering if NASA couldn't sell prints to make a little extra cash? I would love to hang an 8x10 of the smog cloud above L.A. on my wall...
  • I remember reading somewhere a claim that the U.S. once released satellite photos of some geographic features (underground water channels?) as a way to let the Soviets know how good the U.S. surveillence really was. The message: "We know where your missiles are."

    I wonder if there is some message here? Isn't this the kind of data that can be useful for programming cruise missiles and such?

    Not to sound too paranoid or anything :-}
    • No need to sound paranoid. In fact, major funding for this mission was provided by NIMA [nima.mil], primarily for the purpose of generating maps for cruise missiles. However, JPL [nasa.gov] (who ran the mission) managed to get the condition that somewhat lower resolution data would be released to researchers. Actually, I believe US data will be released at full resolution, because high resolution is already available anyway.

      Leeward - In mission control, Houston, for the SRTM mission (but not now a NASA employee).

  • Half empty glasses (Score:4, Interesting)

    by Argy ( 95352 ) on Friday August 03, 2001 @08:16PM (#2160657)
    > Too bad most of the data isn't available yet.

    Is there a rule for Slashdot editors that their comments about good news have to be counter-balancingly negative?

    Considering that pilots and guided missiles may make life-and-death decisions based on this data, taking time to make sure it's accurate and properly processed seems like a good idea. If you have an urgent need, I suppose you could ask for 15,000 CDs of raw data, but all the crunched data should be available by the end of 2002.
    • guided missiles may make life-and-death decisions based on this data

      Well, if my life is concerned in those decisions I'd rather see that missile fly into a mountain :)

  • Internal Server Error

    The server encountered an internal error or misconfiguration and was unable to complete your request.

    Please contact the server administrator, httpd@www-pdsimage.JPL.NASA.GOV and inform them of the time the error occurred, and anything you might have done that may have caused the error.

  • NASA results on Canada.Com? Hmmmmmmmmmmm.........
    • Speaking of NASA and Canada... A couple of years ago, NASA refused to launch a Canadian firm's imaging satellite specifically because it was more advanced than its American counterparts (no insult intended). As I recall, they negotiated with the Chinese to get the thing into orbit...... Oh, and on another note, resolutions better than 1 m are definitely out there. Whatever images have been released, I imagine an order of magnitude superior resolution has been achieved, but that the technology is kept secret.
  • hopefully this will enable flight simulators to render any spot on the planet, by online access to the database for instance.
  • by alewando ( 854 ) on Friday August 03, 2001 @08:31PM (#2160695)
    It's odd that NASA [adequacy.org] is only now getting around to do with the Earth what they've been doing with Mars [nasa.gov] for years. (Follow that link for the pretty pictures [adequacy.org], if nothing else.

    From 1998 to 1999, the Mars Global Surveyor made some 27 million topographical measurements of the red planet. With an average accuracy of 13 meters and sometimes as good as 2 meters. That's not much more than my height.

    Of course, having that precision on Earth would be more difficult with our thicker atmosphere and would raise profound privacy issues [adequacy.org]. On the other hand, government [adequacy.org] spy satellites probably routinely attain that precision without anyone's batting an eyelash. Maybe it's just as well that a civilian [adequacy.org] agency get in on the action too.
    • Actually, the original SRTM was flown back in 1994 (SIR-C and X-SAR) in an effort to update the military's DEMs. I never did hear what happened to that data (probably secret at the time). You can read a bit about it here:

      http://www.jpl.nasa.gov/srtm/spareparts.html
      • Umm... I designed and built some of the hardware for SIR-C (and also SRTM). There was absolutely no military connection to SIR-C. And X-SAR was built by the European space agencies, primarily the Italians on the antenna, and the Germans on the digital hardware, and they also had no military connection. The US military only got involved in SRTM after they saw how well the SIR-C radar worked, and after some of the SIR-C folks went looking for money to upgrade SIR-C to SRTM.

        SIR-C did not make topographic maps, except for one or two special tests using a technique called "repeat pass interferometry", because it did not have the outboard antenna on the 60M mast that SRTM had, and which gave SRTM its "stereo vision". And SIR-C only imaged a few small strips of the earth, each specifically requested by a scientist for some research purpose, or of course a few strips taken for PR purposes. SIR-C did not attempt to make a global map. This data is in the hands of the scientists involved, who supposedly continue to turn out papers based on the data. Also, SIR-C was conceived as a technology test experiment (and is also referred to as SRL - Space Radar Laboratory), used to test a variety of new radar technologies to see how well they worked from a spacebased platform.

        • Yeah, I'm certainly not remembering things very well, I'm sure you are correct. I was contracted to JPL and ERIM to develop software using TOPSAR data in preparation for IFSAR (a DARPA project). Some of the people at JPL involved with IFSAR were also working on SIR-C. From where I sat everything appeared to be either for the military or from the military.

    • Notice that is an average vertical accuracy of 13 meters. But the horizontal accuracy is one one point every 60 kilometers. You are not going to get a very detailed map out of that!

      However, the Magellan [nasa.gov] spacecraft had made somewhat detailed radar images of Venus long before SRTM flew, though not topographic maps, and not to nearly the resolution and accuracy of SRTM.

      • Also consider the *enormous* volume of data required just by doubling the resolution - and of course you also need nearly twice as much data to obtain the overlapping imagery (at the correct angles). While it is true that both Mars and Venus had a more complete radar mapping of their surface before the Earth was so mapped - the quality of the Earth data is going to be so much better. Neither Mars or Venus have as much overlapping stereo radar imagery suitable for very high resolution topographic mapping of their surface. (I'd also point out that both Mars and Venus are smaller planets than the Earth ...).
  • I'll be waiting for an X-Plane [x-plane.com] junkie to get their hands on the data and make a terrain set out of it.
  • Do you think those maps will be buyable or downloadable for the rest of us? I mean, it would be very nice that before going hiking, climbing or something else to evalutate the field in real time 3D before.

    A little CGI would make the job, enter the corners coordinates and they shoot you the map :-)

    Well, i guess i'm dreaming, but it would so cool!
  • What's the deal with the stereo images? When I view them the way I normally view stereograms (let my eyes drift out of focus so I can see four images, and then make the middle two overlap), the 3-d image I see is the reverse of what I would expect: The ocean is a flat plane, but mountains and suchlike are depressions in it, receeding in to the background. (as opposed to coming out towards me like I would expect)

    Am I missing something here? It's hard to believe they would make such a basic mistake as putting the images the wrong way around (although if you swap them, you do get something that works properly for me), so is there some other way of looking at these things? Is it possible to do naked-eye?

    • JPL does say that their images are indeed reversed [nasa.gov]. "The stereo-pair images are reversed; that is to say, the "left-eye" image is on the right side of the pair. This is intentional. It is set up for cross-eyed viewing, as indicated on the image."

      There is a trick that I use to do (almost) naked eye viewing of images that are like this (and I actually find it easier on my eyes). By the way, what are the links to some of the images you were looking at?

      Close your left eye and slide your right hand in from the right, about a foot in front of your face, until it blocks the right image but not the left image. So now your right eye is looking at the left image. Now, while trying to keep that hand approximately where it was, close the right eye and open the left, and similarly slide your left hand in from the left.

      Now you can open both eyes, and do a little fine tuning with your hands, maybe moving them slightly forward or back to get the image visibility right. It sounds kind of complicated, but in practice, I found it pretty easy to do.

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