Month: March 2016

The Benefits of 3D Elevation

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Spring is just around the corner, and that means it’s planting time for the Nation’s farmers. Many of them rely on high-tech farming practices such as in-depth analyses of soil samples, and prescription application of seed, fertilizer, water, pesticides and herbicides, and more.  For all of these applications, three-dimensional elevation data, and a whole host of other cutting-edge information are brought together in a process known as precision farming.

A white paper from the USGS entitled, “3D Elevation – We’ve Got You Covered in all 50 States” plus Puerto Rico provides a number of interesting examples of the benefits of investing in lidar data acquisition on a national scale. This is part of the justification of the 3DEP program.Image shows a cartoon of an airplane on a blue background with laser pulses extending to the ground.

From the paper, “One of the most promising realms of this new technological integration is the advance of 3- dimensional elevation data. A 21st century update to traditional topographic mapping, 3D elevation data relies on high-tech tools like lidar and IfSAR to produce extremely detailed maps of everything from geologic features to buildings.”

The paper explains, “For instance, in Iowa’s corn country, it’s no surprise that 3DEP’s primary benefit is in agriculture and precision farming. By having detailed measurements of elevation, farmers can determine crop rows, crop spacing, fertilizer applications, and irrigation with the utmost accuracy. That makes the entire operation more efficient, yielding more bushels of corn per dollar spent. A national assessment to document business uses indicates that 3DEP could result in at least $18.8 million in new benefits annually to the Hawkeye State. Nationwide, the value to America’s farmers of public domain lidar for all agriculture and precision farming is potentially worth up to $2 billion annually.

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Apple patents a new type of LiDAR system for 3D mapping

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With Apple’s aggressive expansion into geospatial data has come a new focus on research into foundational sensors and systems related to the field, including a newly granted patent that covers an in-house LiDAR device for more accurately capturing three-dimensional scenes.

The patent — with the somewhat impenetrable moniker “3D depth point cloud from timing flight of 2D scanned light beam pulses” — lays out the hardware and functional specifications of a new LiDAR sensor. Apple’s design unsurprisingly includes a fixed mirror, a scanning mirror, a photodetector and a laser emitter.

 

Images: Apple’s new LiDAR system, A Velodyne LiDAR system on Apple’s mapping vans

Apple chose to pursue its own LiDAR technology because current sensing techniques could suffer from “excessive power consumption, limited x-y resolution, limited depth resolution or accuracy, limited frame rate, and long product development cycles,” according to the patent. The company’s new system would alleviate some or all of these issues. Accuracy in three-dimensional spatial data is especially important to Apple as the company ramps up its own in-house mapping efforts.

In addition to mass consumer products like the Apple Maps app, this kind of hyper-accurate mapping data is vital to the development of self-driving vehicles. Apple has long been rumored to be working on an autonomous “Apple Car,” for which the new invention could be a good fit.

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Ocean acidification observed in Arabian Sea

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The Arabian Sea, cradling a diversity of marine habitats including coral reefs, is witnessing acidification of its surface waters, a consequence of excessive carbon dioxide in the atmosphere, say Indian scientists.

Using remote sensing, researchers collected and analysed data spanning ten years with the focus on five parameters that directly correlate with carbon condition of the ocean surface. The idea was to monitor the status of two important regions of the Indian Ocean: the Arabian Sea and the Bay of Bengal.2016-03-21

Arabian Sea, encompassing the northwestern sector of the Indian Ocean, covers a total area of around 3,862,000 sq. km. It is enclosed in the north by Iran and Pakistan, to the west by the Horn of Africa and the Arabian Peninsula and to the east by the Indian Peninsula.

The world’s oceans are alkaline, with a pH factor a little over 7. Anything below that number makes the water less alkaline and more acidic. Pure water is neither alkaline nor acidic.

“In this study we have also taken into account the Andaman Sea lying adjacent to Bay of Bengal,” said Chanda. Oceans act as a huge carbon sink and absorb at least a quarter of the carbon dioxide emissions from coal, oil and gas. As carbon dioxide dissolves, the sea water becomes acidic.

And even though the water bodies are immense, ocean acidification can have a significant impact on marine life – especially the ones that build their skeletons and shells from calcium – over the years, scientists warn.

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Gridded Bathymetry Data :GEBCO

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GEBCO stands for General Bathymetry Chart of the Oceans. GEBCO aims to provide the most authoritative publicly available bathymetric data sets for the world’s oceans.EBCO’s gridded bathymetric data sets are global terrain models for ocean and land and include the

  • GEBCO_2014 Grid — a global 30 arc-second interval grid
  • GEBCO One Minute Grid — a one arc-minute interval grid. Last updated in 2008. Please note that there are no plans for further development of this data set.

In order to assist and encourage further participation in bathymetric grid development work, GEBCO has created a technical reference manual, the IHO-IOC GEBCO Cook Book, on how to build bathymetric grids.
Grid display software used to view and access data from GEBCO's gridded bathymetric data sets

The GEBCO_2014 Grid is available to download for user-defined areas in netCDF, Esri ASCII raster or INT16 GeoTiff formats. The GEBCO One Minute Grid is available in netCDF only.

In netCDF format the grids are available as either two-dimensional (2D) or one-dimensional (1D) array grid files. You can download data for a user-defined area or the complete global grid. The 1D array grids are for use with GEBCO’s Grid Display Software so are only available as a global grid.                                                         (Grid Display Software)

Data Source

Download IHO-IOC GEBCO Cook Book

Grid display software

Landsat Satellite Spots Sunken Ships

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Using data from the NASA/USGS Landsat 8 satellite, researchers have detected sediment plumes extending as far as four kilometers downstream from shallow shipwreck sites, demonstrating how satellites may be used to locate the watery graves of coastal shipwrecks. The new study, conducted in a coastal area of Belgium, was published in the Journal of Archaeological Science.In this natural-color Landsat image, long sediment plumes extend from the wreck sites of the SS Sansip and SS Samvurn. Insets show elevation models (created by a multibeam echosounder) of the wrecks on the seafloor. (Credit: NASA/USGS Landsat/Jesse Allen/NASA Earth Observatory/Matthias Baeye et al)

The researchers started with the known locations of four fully submerged shipwrecks in their study site: the SS Sansip, which the authors explain was a 135-meter U.S. Liberty ship that sank after striking a mine in December 1944; the SS Samvurn, a similar ship that met the same fate the very next month; the SS Nippon, a ship that sank after a maritime collision in 1938; and the SS Neutron, a small 51-meter steel cargo vessel that fell victim to an uncharted navigation hazard, presumed to be the SS Sansip.

Using 21 Landsat 8 images and tidal models, the researchers mapped sediment plumes extending from the wreck locations. They found that the two ships with substantial portions of their structure unburied created sediment plumes that could be traced downstream during ebb and flood tides.

Image Description: In this natural-color Landsat image, long sediment plumes extend from the wreck sites of the SS Sansip and SS Samvurn. Insets show elevation models (created by a multibeam echosounder) of the wrecks on the seafloor. (Credit: NASA/USGS Landsat/Jesse Allen/NASA Earth Observatory/Matthias Baeye et al)

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Mars InSight Mission : Target May 2018

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NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission to study the deep interior of Mars is targeting a new launch window that begins May 5, 2018, with a Mars landing scheduled for Nov. 26, 2018.

InSight’s primary goal is to help us understand how rocky planets — including Earth — formed and evolved. The spacecraft had been on track to launch this month until a vacuum leak in its prime science instrument prompted NASA in December to suspend preparations for launch.

Artist's Concept of InSight Lander on Mars

Image credit: NASA/JPL-Caltech

JPL manages InSight for NASA’s Science Mission Directorate. InSight is part of NASA’s Discovery Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama. The InSight spacecraft, including cruise stage and lander, was built and tested by Lockheed Martin Space Systems in Denver. It was delivered to Vandenberg Air Force Base, California, in December 2015 in preparation for launch, and returned to Lockheed Martin’s Colorado facility last month for storage until spacecraft preparations resume in 2017.

NASA is on an ambitious journey to Mars that includes sending humans to the Red Planet, and that work remains on track. Robotic spacecraft are leading the way for NASA’s Mars Exploration Program, with the upcoming Mars 2020 rover being designed and built, the Opportunity and Curiosity rovers exploring the Martian surface, the Odyssey and Mars Reconnaissance Orbiter spacecraft currently orbiting the planet, along with the Mars Atmosphere and Volatile Evolution Mission (MAVEN) orbiter, which is helping scientists understand what happened to the Martian atmosphere.

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IRNSS-1F : ISRO’s New Milestone

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IRNSS-1F is the sixth navigation satellite of the seven satellites constituting the Indian Regional Navigation Satellite System (IRNSS) space segment. Its predecessors, IRNSS-1A, 1B, 1C, 1D and 1E were successfully launched by PSLV-C22, PSLV-C24, PSLV-C26, PSLV-C27 and PSLV-C31 in July 2013, April 2014, October 2014, March 2015 and January 2016 respectively. All the five satellites are functioning satisfactorily from their designated orbital positions.

IRNSS-1F has a lift-off mass of 1425 kg. The configuration of IRNSS-1F is similar to that of IRNSS-1A, 1B, 1C, 1D and 1E. The two solar arrays of IRNSS-1F consisting of Ultra Triple Junction solar cells generate about 1660 Watts of electrical power. Sun and Star sensors as well as gyroscopes, provide orientation reference for the satellite. Special thermal control schemes have been designed and implemented for some of the critical elements such as atomic clocks. The Attitude and Orbit Control System (AOCS) of IRNSS-1F maintains the satellite’s orientation with the help of reaction wheels, magnetic torques and thrusters. Its propulsion system consists of a Liquid Apogee Motor (LAM) and thrusters.

IRNSS -1F carries two types of payloads – navigation payload and ranging payload. The navigation payload of IRNSS-1F will transmit navigation service signals to the users. This payload will be operating in L5 band and S band. A highly accurate Rubidium atomic clock is part of the navigation payload of the satellite. The ranging payload of IRNSS-1F consists of a C-band transponder, which facilitates accurate determination of the range of the satellite. IRNSS-1F also carries Corner Cube Retro Reflectors for laser ranging.

IRNSS-1F was launched by PSLV-C32 into a sub Geosynchronous Transfer Orbit (sub GTO) on March 10, 2016 at 16:01 hrs (IST) from Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota.

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ISRO’s Satellite Navigation Programme