![]() Then select 'DisplayOne File' | 'Display GeoTiff IEEE FP 32 Elevation Image' | 'Flipped'. To produce a corrected file, select 'File' | 'Open' and open the elevation file. It is necessary to flip the elevation postings without changing the georeferencing in order to use the data. The elevation data is saved by NASA in GeoTiff format using IEEE floating point 32 bit representation for the elevation postings. PANCROMA has a utility for correcting this problem. These can be used by other applications like the excellent 3DEM for preparing terrain models by draping the image over the elevation model.Īs mentioned, an issue with this data is that the elevation files are saved mirror flipped around the center latitude line. An example USGS NAIP image dowloaded from WorldWind is shown below.Īfter selecting your area of interest, you can save both the image file and the elevation files separately. As far as I can tell, the Urban Ortho Image layer and the USGS topographic map data layers have not been implemented in the demonstration applet. The USDA NAIP and USGS NAIP USGS data layers seem to have the highest resolution, apparently around 2m. Note that only the first four data layers are relevant for areas outside of the United States. I found that checking the following layers was helpful: You will need to check some of the relevant data layers in order to best navigate the virtual globe. There is a slight glitch to doing this as the elevation files are downloaded mirror flipped over the central East-West latitude line, but PANCROMA has a utility to correct this.Īfter navigating to the Demo Applications page, scroll down to the 'Exporting Surface Imagery and Elevations' utility. This greatly facilitates draping the image over the DEM to create terrain models. Using this program, it is possible to download co-registered satellite imagery along with SRTM DEM data. This article examines one of them, the 'Exporting Surface Imagery and Elevations' utility. Some of these are very interesting and useful. NASA posts demonstration Java applets at its Java SDK site. NASA also released the WorldWind SDK, an API designed to let developers access and extend the core capabilities. Unlike Google Earth, WorldWind is an open source application, and has been quietly adding capabilities, thanks in large part to its connection with NASA and its access to their data. WorldWind appeared around 2004 (about the same time as Google Earth) but was overshadowed into near obscurity by the massive marketing power of Google. Many GIS users are familiar with the NASA WorldWind virtual globe utility as the less well-known cousin of the extremely popular Google Earth application. states in mid-May 2022.See additional satellite image processing articles at menu selection 'White Papers' Plumes of dust recently reached Florida, Texas, and other southern U.S. Those summer seasonal wind patterns can carry the dust from Africa to the Caribbean and the Gulf of Mexico. Dust storms in the summer tend to loft material higher into the atmosphere, allowing plumes to travel thousands of kilometers on high-level winds. In winter and spring storms, Saharan dust often ends up fertilizing the nutrient-poor soils of the Amazon rainforest. ![]() The Sahara Desert is by far Earth’s largest source of airborne dust, and the storms can arise at any time of year. And dust-rich with iron and other minerals that plants and phytoplankton need-provides natural fertilizer for ocean ecosystems and lands downwind. Dust can degrade air quality and have negative health effects, particularly for people with lung conditions. The airborne particles absorb and reflect sunlight-altering the amount of solar energy reaching the surface-and can also promote or reduce cloud and storm formation, depending on other atmospheric conditions. Natural-color satellite imagery from May 30 to June 6 showed the storm’s progression across the water.ĭust plays a major role in Earth’s climate and biological systems. NASA satellite sensors that track aerosol optical depth observed substantial increases in sunlight-reflecting particles over the region starting on May 29 and continuing to June 6. NASA’s Earth Polychromatic Imaging Camera on NOAA’s DSCOVR satellite also acquired hemisphere-wide views of the event on June 3 and June 4. The Visible Infrared Imaging Radiometer Suite (VIIRS) on the NOAA-20 satellite acquired natural-color images (above) of dust on June 3 and 5, 2022, when the plumes were most distinct. A fresh supply of dust was airlifted from the Sahara in early June 2022, and some of it appeared to be headed for the Americas. Winds pick up an estimated 100 million tons of dust from the Sahara Desert each year, and a sizable portion of it blows out over the North Atlantic Ocean. ![]()
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