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GPS technology improves weather forecasting - Spatial Source : Australasia's magazine for the surveying, mapping and geoinformation industries

GPS technology improves weather forecasting - Spatial Source : Australasia's magazine for the surveying, mapping and geoinformation industries | Remote Sensing News | Scoop.it

Researchers at RMIT University's SPACE Research Centre and the Bureau of Meteorology are using GPS and low earth orbit satellites to provide an additional type of temperature profile observation for use in weather forecasting computer models.

The computer models draw on about a hundred thousand million current weather observations, including data from 30 to 40 complementary satellite instruments, to generate the information used by meteorologists to prepare weather forecasts.

RMIT Adjunct Professor John Le Marshall, Research Program leader at the Bureau of Meteorology and former Inaugural Director of the Joint Center for Satellite Data Assimilation, a joint NOAA, NASA and DOD research initiative in Washington, said: "What we've found through our work with RMIT's SPACE research team is that the GPS data improves the real-time temperature field and the cross-calibration of the data from a number of satellite instruments. This in turn significantly increases the usable quality of the satellite observations.

"We are actually able to measure the amount of bending in the GPS beam as it passes through the atmosphere. We can then use that knowledge to more accurately measure atmospheric temperatures and use this to improve temperature fields and calibrate other satellite readings. This extra information, in the data-sparse southern hemisphere, is now making our forecasts more accurate.".......

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The white marble: Satellite captures stunning shot of Earth in vivid detail from 512 miles above the North Pole

The white marble: Satellite captures stunning shot of Earth in vivid detail from 512 miles above the North Pole | Remote Sensing News | Scoop.it
This stunning picture, taken from 512 miles above the North Pole, gives us a very different - even dizzying - take on our planet, as we see our usual blue marble tilted on its side and shrouded in snow.

 

We are perhaps a bit too used to seeing the Earth the 'right' way up.
So this stunning picture, taken from 512 miles above the North Pole, gives us a very different - even dizzying - take on our planet, as we see our usual blue marble tilted on its side and shrouded in snow.
Russia and Europe can be seen spinning underneath the pole, much of it buried under a huge swathe of white - a mix of both cloud cover and snow.
For once, Britain gets a reprieve, with a bit of sunshine giving us and central Europe some blue skies through which, if we had powerful enough eyes, we could see the satellite responsible for this picture looking back at us.

Read more: http://www.dailymail.co.uk/sciencetech/article-2161558/The-WHITE-marble-Satellite-captures-stunning-shot-snow-drenched-Earth-vivid-512-miles-North-Pole.html#ixzz1yX8chjey

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On the Cutting Edge of Emergency Management : Earth Imaging Journal: Remote Sensing, Satellite Images, Satellite Imagery

On the Cutting Edge of Emergency Management : Earth Imaging Journal: Remote Sensing, Satellite Images, Satellite Imagery | Remote Sensing News | Scoop.it

THE U.S. GEOLOGICAL SURVEY’S EMERGENCY OPERATIONS OFFICE GIVES EMERGENCY MANAGERS FAST ACCESS TO CRITICAL SATELLITE IMAGERY.

 

The use of geographic information system (GIS) technology is gaining widespread acceptance in the disaster response and management community. Emergency managers useGISfor preparedness, as well as for event management and follow up. Pre-incidentGISinformation includes location and status of critical infrastructure and emergency services, as well as identifying areas susceptible to damage. During an event, up-to-dateGISinformation helps emergency managers deploy and prioritize the use of assets. As efforts move into recovery and rebuilding,GIStechnology continues to assist in damage assessment, construction planning and mitigation of future incidents.

 Every GIShas an enormous appetite for geographic data, especially up-to-date maps and images. Satellite and airborne remote sensing plays an important role in providing both pre- and post-incident imagery. Although there exists a large array of government and private imaging sources for information, finding and obtaining the needed imagery in a short time frame—as is usually the case in an emergency situation—can become a daunting task forGIS operators.

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Global Positioning System surveys

Global Positioning System surveys | Remote Sensing News | Scoop.it

Global Positioning System surveys with such titles contained in a digital textbook book is published in the GIS Community by PT. Geovisi Mitratama. The series of books in gif format which can be downloaded in the GIS community mailing list. The following excerpt from the Introduction to the eBook contents of the GPS: Global Positioning System is a tool to determine the position in a particular coordinate system. The first system was developed by the U.S. to put a few tens of satellites in the sky spread out the earth in a satellite constellation systm. The book is a training in the use of GPS by Garmin series type III / V, which is divided on which is technically the use of GPS which includes: A. The introduction of satellite layer and the minimum requirement satellite 2. Obtaining coordinates 3. Setting the datum and coordinate system 4. Tracking using GPS track-log 5. Storing data, name data, display data 6. Importing data using GPS MapSource software, convert the data into a spatial data format to another.........

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Using LiDAR, filmmaker discovers “lost city” | Ars Technica

Using LiDAR, filmmaker discovers “lost city” | Ars Technica | Remote Sensing News | Scoop.it
Cinematographer Steve Elkins announced last week that by using LiDAR (light detection and ranging), he discovered "what appears to be evidence of archaeological ruins in an area long rumored to contain the legendary lost city of Ciudad Blanca." The phrasing "lost city" is problematic, however: it's hard to lose a city when the city itself is a myth.

The mapping project, conducted over 40 hours split between seven flights during April and May, was led by Elkins' group, UTL Scientific. Participants include the thriller writer Douglas Preston, who is the former editor at the American Museum of Natural History. The project took place in conjunction with the government of Honduras with the help of technicians from the National Science Foundation's National Center for Airborne Laser Mapping and professors from the University of Houston.

 

The tech

The LiDAR survey covered the history-rich northeastern Mosquitia region of Honduras. They overflew the area, sending "25 to 50 laser pulses per square meter—a total of more than four billion laser shots" to the ground, according to the University of Houston, and capturing differences in elevation of as little as four inches. This process can look underneath forest canopies, producing a 3D map of areas in hours or days that an overland, machete-hacking expedition might take years to do.

The UTL survey employed an Optech Gemini Airborne Laser Scanner aboard a Cessna 337 Skymaster plane overflying 923 square kilometers at a height of 600 to 1,000 meters above the ground. According to UTL, 4 billion LiDAR "shots" were fired at a pulse rate of 125KHz.

Modern, high-intensity LiDAR is a recent innovation. The first archaeologists to use it to startling effect were Arlen and Diane Chase at Caracol in Belize, mapping more ground in four days, they said, than they had in their previous 25 years of exploration of the area.

Chris Fisher, as we detailed in a previous article, used it to extend the breadth and establish the importance of the Purepechan city of Sacapu Angamuco in western Mexico.

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Introducing ArcGIS 10.1 | ArcNews

Introducing ArcGIS 10.1 | ArcNews | Remote Sensing News | Scoop.it
The release of ArcGIS 10.1 signals a major development in the way geographic information will be accessed and managed by GIS professionals and their organizations in the years to come. ArcGIS 10.1 gives GIS professionals a complete GIS that further integrates desktops and servers, as well as mobile and web applications. It provides organizations with the additional tools and infrastructure they need to extend the reach of their existing GIS. It also improves organizations' ability to transition to next-generation GIS concepts and platforms without jeopardizing their current GIS investments.

New to ArcGIS Online is ArcGIS Online for organizations—a customizable, web-based system designed for professionals who want to manage their organizations' geospatial content using cloud tools and infrastructure. It allows administrative control over data creation and access while making geographic information easily available to others within the organization, as well as beyond the organization in collaborative efforts with others. (see "The City of Salem, Oregon, Broadens the Reach of GIS").....

 

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Remote Sensing of Suspended Particulate Matter in Himalayan Lakes : CLIMATE HIMALAYA

Remote Sensing of Suspended Particulate Matter in Himalayan Lakes : CLIMATE HIMALAYA | Remote Sensing News | Scoop.it

Bio-One: This study presents satellite data and in situ measurements to estimate the concentration of suspended solids in high altitude and remote lakes of the Himalayas. Suspended particulate matter (SPM) concentrations measured in 13 lakes to the south of Mount Everest (Nepal) in October 2008 and reflectance values of the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR- 2) onboard ALOS, acquired a few days after the fieldwork activities concluded, were combined to build a relationship (R2 5 0.921) for mapping SPM concentrations in lakes of the Mount Everest region. The satellite-derived SPM concentrations were compared with in situ data (R2 5 0.924) collected in the same period in 4 additional lakes, located to the north of Mount Everest (Tibet, China). The 13 water samples collected in lakes in Nepal were also used to investigate the absorption coefficients of particles ap(l) and colored, dissolved organic matter a CDOM(l), with the aim of parameterizing a bio-optical model.
An accurate model (R2 5 0.965) to estimate SPM concentrations from ap(l) was found and could be adopted in the future for retrieving suspended solids from satellite imagery independently of ground measurements. In such a remote area, remote sensing was demonstrated to be a suitable tool to characterize the state of lakes, whose loads of suspended solids might be assumed to be direct and quick-responding indicators of de-glaciation processes and glacier–lake interactions. As a macro descriptor of water quality, the assessment of SPM in glacial lakes of the Himalayas might also be of interest for resource use in the downstream region.
Global warming has resulted in a large-scale retreat of glaciers throughout the world (Oerlemans 2005). The evidence for this is particularly strong in high-altitude areas, such as the central Himalaya (Solomon et al 2007; Hambrey et al 2009; Quincey et al 2009; Ye et al 2009), where widespread recession is evident from the rapid growth in the number and size of glacial lakes (Chikita et al 2001; Quincey et al 2007; Bolch et al 2008; Tartari et al 2008; Wang et al 2008; Ye et al 2009). De-glaciation processes are also revealed by the amount of suspended solids transported by glacier waters melting into the lake (Østrem et al 2005),with consequences for light propagation in the water body. If glacier water influx into a lake increases,then the density will increase, and this affects light scattering.
For decreased melt water input, absorption because of water increases and the preferential red absorption because of water are enhanced. In lakes that have no glacial input, lake water is clear, and there is almost no scattering or absorption because of suspended matter (Kargel et al 2005). The recognition of lakes hydraulically connected to the glacier hydrological systems, hence full of silt (eg moraine-dammed supra glacial lakes),as opposed to those that are isolated (eg cirque lakes),would add value to studies (eg Tartari et al 2008) on processes of glacial-lake formation and expansion. Ultimately, these studies might contribute to an assessment of glacial lake hazard, because some moraine-dammed lakes may be unstable and potentially susceptible to sudden discharge of large volumes of water and debris, which could cause floods hazardous to communities and infrastructure downstream (Richardson and Reynolds 2000; Kattelmann 2003; Bajracharya et al 2007; Quincey et al 2007; Bolch et al 2008).
Besides indicating the dynamics of the interaction between glaciers and lakes, suspended solids play a fundamental role in the aquatic system itself. They regulate the transport routes of all types of materials and contaminants in aquatic ecosystems (Wetzel 1983) and ultimately determine the primary productivity of water (Zhang et al 2008). As an indicator of water clarity (eg Secchi disk depth and water transparency, see Ha¢ª kanson et al 2007),suspended solid concentration is also a macro-descriptor of water quality directly related to many variables of general use in lake management (Baban 1999). Water quality monitoring in the Himalayan region would contribute to proper management of some glacial lakes that could provide valuable water, energy, and tourism resources to local residents in the downstream regions (Komori 2008; Salerno et al 2008).

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Ndvi – a Vegetative Index

Ndvi – a Vegetative Index | Remote Sensing News | Scoop.it
NDVI is a commonly used vegetative index in remote sensing analysis to distinguish the vegetation from non-vegetation features recorded in satellite images.
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USGS Release: Aging Landsat 5 Changes Glasses

USGS Release: Aging Landsat 5 Changes Glasses | Remote Sensing News | Scoop.it
Landsat 5 has orbited Earth over 150,000 times since it was launched in 1984, making it the longest-operating Earth observing satellite of its kind. During this time, two data collection instruments onboard Landsat 5 — the thematic mapper (TM) and the multi-spectral scanner (MSS) — have transmitted over five million images of land conditions to U.S. and international ground stations.

In November 2011 an electronic malfunction in the TM transmitter forced a suspension of routine imaging. Now, after months of trying without success to restore daily TM image transmissions, USGS flight engineers will attempt only a few additional image acquisitions over specific sensor-calibration sites as the TM transmitter nears complete failure.

On a positive note, the MSS instrument onboard Landsat 5 was recently powered back on in a test mode after more than a decade of silence.

"The resurrection of the MSS a decade after it was last powered up and 25 years beyond its nominal lifespan is welcome news indeed," said USGS Director Marcia McNutt. "While not a complete replacement for the loss of the Thematic Mapper, it does provide some insurance for ensuring Landsat data continuity should Landsat 7 fail prior to Landsat 8 achieving orbit next year."

The MSS sensor, the forerunner of TM, gathers data in fewer spectral bands than TM, has lower pixel resolution, and does not acquire thermal data. However, each MSS scene covers the same area as a TM scene, approximately 12,000 square miles. The USGS is currently acquiring MSS data only over the United States. Landsat International Cooperator stations may begin downlinking data from other parts of the globe, depending on their intentions and ability to establish MSS data processing capabilities.

It will take some months for MSS data to be integrated into current production systems and be made publically available. Landsat 5 has sufficient fuel to operate through 2013.

Landsat 7, the other active Landsat spacecraft operated by the USGS, continues to collect images worldwide, as it has done since 1999. In 2003, Landsat 7 experienced a hardware failure that causes a 22% loss of data in every image. In the intervening nine years, many techniques have been developed to partially compensate for the data loss and leverage the remaining data for scientific analysis and resource monitoring.

The next Landsat, the Landsat Data Continuity Mission (LDCM or Landsat 8), is scheduled for launch in January 2013. Following launch, it will become Landsat 8 and is expected to extend the Landsat record for at least another five years.

Once Landsat 8 is fully operational, the collection of MMS data from Landsat 5 will be re-evaluated.

For further details and the latest information about the status of Landsat 5, visit the USGS Landsat Missions website.

The Landsat Program is a series of Earth observing satellite missions jointly managed by the U.S. Geological Survey and NASA. Landsat satellites have been consistently gathering data about our planet since 1972. They continue to improve and expand this unparalleled record of Earth's changing landscapes for the benefit of all.

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GEO Informatics | In the Spotlight | Satellite versus aerial images – not always a matter of choice!

GEO Informatics | In the Spotlight | Satellite versus aerial images – not always a matter of choice! | Remote Sensing News | Scoop.it
When selecting raw data for value adding we do have today many more options than ever before. Images are very much appreciated and preferred because of their high information content. When it comes to non-terrestrial platforms we do have the choice between satellite, regular aerial and UAV imagery. The “choice” option cannot always be realized, because very often the circumstances, as project parameters, image availability, costs, etc. will dictate the selection and use.

High-resolution satellite images are on the market for a number of years, most of them providing stereo-processing capabilities. Imagery with 50 cm footprint is readily available, with the prospect that GeoEye-2 with 30 cm footprint will be launched in 2013.
This puts satellite images in competition with aerial imagery at medium resolution. In this context we have to understand that both data sources do have distinct advantages and disadvantages, which are briefly listed here.

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Imaging to drive remote sensing satellite market

Imaging to drive remote sensing satellite market | Remote Sensing News | Scoop.it
More than a hundred remote sensing satellites will be built over the next decade, at an estimated value of $17 billion.

The need for more and better imaging data will be the major driver behind a “healthy” market for remote sensing satellites over the next ten years, according to a new study by US-based Forecast International.

Specializing in the aerospace and defense sectors, analysts at the company say that 108 new remote sensing satellites will be produced between now and 2021 – equivalent to a market worth $17 billion.

William Otrove, author of the report, points out that while military and government customers remain the primary users of that imagery, the commercial sector is – as with aerospace in general – set to play an increasingly important role.

Otrove’s study notes how the recent wars in Iraq and Afghanistan have seen satellite imagery come to the fore: “The success of space-based imagery accentuated the necessity of these systems in establishing situational awareness on the battlefield,” he says.

Commercial satellites also play a vital part in the gathering of military intelligence, he adds, through programs such as the US National Geospatial Intelligence Agency’s Enhanced View.

But that imagery is also playing an important role in other areas. One example is the American Association for the Advancement of Science (AAAS) Geospatial Technologies and Human Rights Project, where satellite imagery is being used for remote documentation of human right violations.

Recent studies by the AAAS team include satellite-based assessment of damage to 24 villages in Tskhinvali, Georgia, during the conflict that broke out between Georgia and neighboring Russia in August 2008. That study found “obvious craters from munitions and tracks from the presumed movement of military vehicles, which resulted in clear damage to the vegetated areas throughout the region”.

Other satellite imaging studies have shown obliterated villages in Darfur, part of what is now South Sudan, as well as destroyed settlements in Zimbabwe, and much more besides.

But one of the most difficult aspects of documenting the impact of conflicts in isolated parts of the word is to count the number of people affected – largely because a single person would be represented by just a solitary pixel in a typical satellite image, which is collected with a Cassegrain telescope from several hundred kilometers above the Earth.

Wider world view
At the recent SPIE Defense, Security and Sensing (DSS) conference and trade show in Baltimore, US, a team from the European Commission’s Joint Research Centre in Italy described a new method that uses a wider range of spectral bands now available via the WorldView-2 satellite, part of the DigitalGlobe remote sensing constellation.

As well as visible-range spectral bands, WorldView-2 provides two different near-infrared views of the Earth, to a multispectral resolution of 1.8 meters.

According to Otrove, as well as using more of the infrared spectrum, governments are increasingly turning to the non-optical capability of synthetic aperture radar, which can be used to generate images through cloud cover and at night.

In the growth area of commercial and private use, the analyst says that applications include urban planning, agriculture, mapping and transportation.

Key system integrators in the remote sensing satellite industry include Europe’s EADS Astrium and Thales Alania Space, Lockheed Martin and Ball Corporation in the US, and Japan’s Mitsubishi Electric.

“The opportunities for manufacturers will increase as remote sensing applications and demand rises,” reports Otrove. “However, maintaining a competitive edge will require upgrading satellites with the latest technology, expanding constellations and replacing older satellites.”

Last month, DigitalGlobe revealed details of one of the estimated 108 new remote sensing platforms, in the form of its planned WorldView-3 satellite, scheduled for launch in 2014. In addition to offering 0.31 meter resolution panchromatic and eight-band multispectral imagery, it has been licensed by the US National Oceanic and Atmospheric Administration (NOAA) to collect eight-band short-wave infrared (SWIR) data.

According to the company, this will make DigitalGlobe the only company with multi-band SWIR capabilities, greatly expanding the range of customer applications available.

”We had many options, and after months of working with both government and commercial customers, we chose to add the SWIR bands that will best address our customers' needs,” stated Walter Scott, DigitalGlobe’s founder, executive VP and CTO.

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Landsat : Looking at Earth's Surface

Looking at Earth's Surface http://www.nasa.gov/multimedia/videogallery/index.html?media_id=11886044...

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Satellite Image of Sahara Desert – “The Great Desert”

Satellite Image of Sahara Desert – “The Great Desert” | Remote Sensing News | Scoop.it
GeoEye-1 (0.5m) Satellite Image of Sahara Desert in East Algeria Click image to view in high resolution. (Copyright© GeoEye and Courtesy of Satellite Imaging Corporation. All Rights Reserved) This...
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Quantum GIS (QGIS) 1.8.0 Released | Slashgeo.org

Quantum GIS (QGIS) 1.8.0 Released | Slashgeo.org | Remote Sensing News | Scoop.it

A lot of geoblogs mentioned the release of Quantum GiS 1.8.0. QGIS is one of the most mature and widely used open source desktop GIS software, with tons of useful community-contributed plugins. Version 1.8.0 is clearly a major update of this already excellent GIS software.

The list of new features is quite long, here's a few of them:

 

* QGIS Browser: a stand alone app and a new panel in QGIS. The browser lets you easily navigate your file system and connection based (PostGIS, WFS etc.) datasets, preview them and drag and drop items into the canvas.
* DB Manager: the DB manager is now officially part of QGIS core. You can drag layers from the QGIS Browser into DB Manager and it will import your layer into your spatial database.
New symbol layer types: Line Pattern Fill, Point Pattern Fill.
* Terrain Analysis Plugin: a new core plugin was added for doing terrain analysis - and it can make really good looking colored relief maps.
* Ellipse renderer: a new symbol layer type to render ellipse shapes (and also rectangles, triangles, crosses) by specifying width and height.
* Support for nesting projects within other projects: embed content from other project files.
Layer grouping: Option to add layers to selected or active group.
* Customization: Allows setting up simplified QGIS interface by hiding various components of main window and widgets in dialogs.
* Action Tool: accessible from the map tools toolbar. It allows you to click on a vector feature and execute an action.
* Pan To Selected tool: Pans the map to selected feature(s); does not change the zoom level.
* Updated CRS selector dialog
* Legend-independent drawing order: The order seen in the legend can be different from the display order.
* Other features include: MSSQL Spatial Support, Expression based labelling, Heatmap tool, WFS support in QGIS Server, and much more.....

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Aging Landsat 5 switches back to MSS - Spatial Source : surveying, mapping and geoinformation industries

Aging Landsat 5 switches back to MSS - Spatial Source :  surveying, mapping and geoinformation industries | Remote Sensing News | Scoop.it

Landsat 5 has orbited Earth over 150,000 times since it was launched in 1984, making it the longest-operating Earth observation satellite of its kind. During this time, two data collection instruments onboard Landsat 5 – the thematic mapper (TM) and the multi-spectral scanner (MSS) – have transmitted over five million images of land conditions to US and international ground stations.

In November 2011, an electronic malfunction in the TM transmitter forced a suspension of routine imaging. Now, after months of trying without success to restore daily TM image transmissions, USGS flight engineers will attempt only a few additional image acquisitions over specific sensor-calibration sites as the TM transmitter nears complete failure.

On a positive note, the MSS instrument onboard Landsat 5 was recently powered back on in a test mode after more than a decade of silence.

"The resurrection of the MSS a decade after it was last powered up and 25 years beyond its nominal lifespan is welcome news indeed," said USGS Director Marcia McNutt. "While not a complete replacement for the loss of the Thematic Mapper, it does provide some insurance for ensuring Landsat data continuity should Landsat 7 fail prior to Landsat 8 achieving orbit next year."

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Calculating Variable Width Buffers on a Stream Segment Based on Elevation « Gretchen Peterson's Blog

Calculating Variable Width Buffers on a Stream Segment Based on Elevation « Gretchen Peterson's Blog | Remote Sensing News | Scoop.it

METHODS
In the example below, the stream line is shown in blue and some retention ponds are visible in the aerial photo near that stream:

Next, we take that stream segment and make it into a grid with the same extent as our elevation grid. It looks like this, where each cell has a slightly different elevation value (streams generally go downhill!):

Then we create a Euclidean allocation grid from those stream elevations. It just assigns the elevation of the nearest source stream pixel to all of the other cells. For example, the yellow area is all assigned pixel values of 148817 (meters X 100, since I have also multiplied the elevation grid by 100 to make it into an integer). That stream pixel value that the yellow is emanating out from has a value of 148817.

The next step is to subtract the Euclidean grid from the true elevation grid so that, for each pixel, we determine how much higher that pixel is than the elevation of the closest stream pixel. Ideally, this would produce a variable width buffer once you set a threshold for how high you want to go. For example, if I set the threshold at 1/2′ (which is 15 units in my data, remember it is meters and multiplied by 100), then the resulting “buffer” looks like this, in green:

The area shaded in green is a model of where the locations around the stream are within a half-foot elevation rise of the stream. Areas that are not in green are higher than half a foot of the stream. Note that I’ve left out some of the details which involve subtracting the Euc grid from the elevation grid, then testing (with a con statement in ArcMap in this case) whether or not the result is above 15 or lower than 15, where it is lower than 15, we assign the pixel a 1 and where it is above 15 we assign a NoData value.......

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Radiometric correction of Landsat images using ENVI 4.x

Radiometric correction of Landsat images using ENVI 4.x | Remote Sensing News | Scoop.it

ENVI ® (the Environment for visualizing Images) is a revolution of digital image processing system. From the beginning of the birth, ENVI has been designed for many specific requirements on who typically use satellite remote sensing data or aerial photographs. ENVI provides data visualization and comprehensive analysis for the image in any size and any type of environment in which innovative and user-friendly.

Atmospheric correction performed on the radiometric image is distorted. Or to say also that the radiometric correction performed due to interference from atmospheric effects as the main source of error. Distortion can occur during data acquisition and transmission or recording of the detectors used in the sensor with the characteristics of errors include: - The existence of the missing pixels - Effects of the atmosphere that causes the shadow scattering object - The appearance of lines caused by the lack of uniformity detectors Correction of the above can use the histogram adjustment method (histogram adjustment). The assumption underlying this method is the lowest pixel value of each channel should be 0. If the value is greater than zero (> 0), then calculated as the bias or offset, and the correction is done by removing the bias, which reduces the overall value of the original spectral channels with a value bias respectively. In ENVI Band Math can be performed with or Dark Substract Basic Tools> Band Math then enter the formula Reduction of the bias, for example: B1-54 done for each band, with each value of bias Basic Tools> Preprocessing> General Purpose Utilities> Dark Substract select the image, then all bands will be corrected (if any bands / channels are in one file) To check the value of vulnerable band / channel Select Basic Tools> Statistics> Statistics Compute

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Ishola Adebayo's curator insight, August 2, 2013 6:52 AM
great but how then is the band math value arrives at?
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Global remote sensing technologies market to grow to $12.4 billion in 2017

Global remote sensing technologies market to grow to $12.4 billion in 2017 | Remote Sensing News | Scoop.it
The global remote sensing technologies market is estimated to reach $8.3 billion in 2011. It is expected to reach $9.1 billion in 2012 and will further grow to $12.4 billion by 2017 at a compound annual growth rate (CAGR) of 6.4%.

Learn about the remote sensing industry, specifically basic types of remote sensing instruments, platforms and technologies, and important applications such as weather forecasting, intelligence gathering, climate change, and public health. Patent analysis and company profiles are provided as well…

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Making a Big SPLASH in Transboundary Water Resources Management

Making a Big SPLASH in Transboundary Water Resources Management | Remote Sensing News | Scoop.it
As pressures on the natural environment from urbanization and economic development increase, we must take responsibility for earth's resources. Because globalization is pervasive and affects almost all aspects of our lives, the effects of our actions are not limited to one country. However, taking effective and coordinated action in transboundary areas that cover more than one country is even more complicated.

In recent years, water resources have become the subject of special concern by citizens and local governments. These concerns have been reflected in European Union (EU) directives. The natural level of geography for monitoring and protecting water resources is the river catchment. [A river catchment is all the land drained by a single river and its tributaries.] EU directives require water resources protection and management at this level.

To this end, Poland and Slovakia built a GIS named PLUSK (or SPLASH) that is designed to serve as a common platform for information exchange, analysis, and surface water and groundwater resources management. The project name comes from combining the international country name abbreviations for Poland (PL) and Slovakia (SK).

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ArcGIS 10: Trabalhando com OpenStreetMap, Bing Maps e outros Serviços

ArcGIS 10: Trabalhando com OpenStreetMap, Bing Maps e outros Serviços | Remote Sensing News | Scoop.it

Trabalhar com mapas online tornou-se um tarefa frequente nos dias de hoje, porém descarregar uma base de mapas online no SIG sem dúvida é uma tarefa muito mais operacional. No mês passado eu publiquei a primeira parte de um tutorial que ensina os passos para descarregar diversos repositórios de mapas no SIG livre Quantum GIS. Hoje chegou a vez de verificar essa tarefa no SIG da ESRI.......

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Extracting an image chunk from a collection of Large MrSid Images | California Soil Resource Lab

Extracting an image chunk from a collection of Large MrSid Images | California Soil Resource Lab | Remote Sensing News | Scoop.it

Recently needed to extract a small "chunk" from a collection of adjacent MrSid mosaics, each about 4Gb in size. Once again, GDAL came to the rescue, and saved much time and agony wile working with very large, compressed, and proprietary-format files. Two lessons learned:
The GDAL VRT format can save a lot of time and effort by providing access to a collection of files without actually altering the originals.
ArcGIS 9.x does not like BigTIFF files. When file sizes approach or exceed 4Gb, the HFA format is a nice alternative.

Have patience, subsetting a chunk out of 5 adjacent MrSid files (4Gb each) took about 7 hours. Fun experiment: extract sub-chunks from each of the constituent sid files and distribute across CPU cores.........

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Futurity.org – The science of steep mountain slopes

Futurity.org – The science of steep mountain slopes | Remote Sensing News | Scoop.it

The findings point to the interplay between terrain uplift associated with plate tectonics and powerful streams cutting into hillsides, leading to erosion in the form of large landslides.
The work, presented online May 27 in Nature Geoscience, shows that once the angle of a slope exceeds 30 degrees—whether from uplift, a rushing stream carving away the bottom of the slope, or a combination of the two—landslide erosion increases significantly until the hillside stabilizes.
“I think the formation of these landscapes could apply to any steep mountain terrain in the world,” says lead author Isaac Larsen, a University of Washington doctoral student in Earth and space sciences.....

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FREC 480--Intro to lmage Processing

FREC 480--Intro to lmage Processing | Remote Sensing News | Scoop.it

This page provides background information on remote sensing, including an overview of sensor technologies an a general discussion of image enhancement, registration and interpretation methods. Subsequent pages detail the specifics of ArcView's Image Analyst extension.

Brief history of remote sensing

Remote sensing technologies have largely been driven by military intelligence needs. Airphotos have been taken from balloons since the 19th century, and from airplanes since the early 20th century. The US relied increasingly heavily on aerial surveillance during World War II. During the Cold War the US used spy planes to monitor Soviet military installations, but by the late 1950's the Soviets had developed the ability to shoot these planes down. Surveillance airphotos of Cuba identified the presence of Soviet military advisors (a US analyst first noticed new soccer fields, and knew that Cubans play baseball but Russians play soccer), and led to detection of Soviet nuclear weapons in Cuba, triggering the Cuban Missile Crisis in 1962.

The need for more secure remote sensing platforms drove US development of unmanned systems, including satellite-based systems. The early unmanned systems, involving rocket launches of robotic cameras that jettisoned film canisters, had very high rates of launch failure and canister recovery failure. By the late 1950's the US had developed scanner technologies as a substitute for photography, and scanners mounted on earth satellites radioed images back to receiving stations in digital form, obviating the need for film canister recovery.

The electromagnetic spectrum

The electromagnetic spectrum includes visible light, radio waves, heat, X-rays and other forms of energy. Electromagnetic radiation (EMR) travels at the speed of light (c = 3 x 108 meters/second) in a sinusoidal (wavy) pattern. Wave components in the electric field and the magnetic field have defined wavelength and frequency. The wavelength is the distance between wave peaks; the frequency is the number of peaks passing a fixed point per unit time. The basic physical relationship between these is

c = wavelength x frequency
and since c is constant, wavelength and frequency are inversely related, so we can characterize EMR by either measure. We typically classify EMR by wavelength, usually measured in micrometers (1 µm = 10-6m). The electromagnetic spectrum includes cosmic rays (<10-7 µm), gamma rays (~10-6 µm), X-rays (~10-4 µm), ultraviolet (0.1--0.4 µm), visible light (0.4--0.7 µm), near infrared (0.7--1.3 µm), mid-infrared: (1.3--3 µm), thermal infrared (3--10 µm), microwave (~105 µm) and TV/radio (~108 µm).......

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Illegal turfcutters to be monitored by aircraft - The Irish Times - Mon, May 21, 2012

Illegal turfcutters to be monitored by aircraft - The Irish Times - Mon, May 21, 2012 | Remote Sensing News | Scoop.it
PRIVATE AIRCRAFT contractors are being hired by the State to work alongside the Defence Forces in gathering evidence against illegal turfcutters.

A total of 10 separate flights have been flown by a private company over boglands this year costing €13,148 with more flights expected over the coming month.

Some €27,226 has been spent on 19 private flights over bogs by the National Parks and Wildlife Service (NPWS) since surveillance began in 2009, according to figures released under the Freedom of Information Act.

Separately, the Department of Defence has spent an additional €13,875 on about 75 flight hours of bog surveillance so far this year.

Usually, two enforcement officers aboard the flights gather photographic evidence of any illegal turf cutting seen from the aircraft.

If suspected illegal activity is discovered personnel on the ground are notified and investigate on the ground level, often accompanied by the Garda.

Independent TD Luke Flanagan, a spokesman for the Turf Cutters and Contractors Association, said that the surveillance of bogs was a poor use of public funds. “I think it is a complete and utter waste of money, turfcutters aren’t exactly going around murdering people.

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