Is Remote Sensing The Answer To Today's Agriculture Problems? Wheat Growers Turn To Aerial Imagery To Overcome Economic, Environmental Challenges

Today's wheat growers face many economic and environmental challenges, but arguably their greatest challenge is the efficient use of fertilizer.


Growers need to apply nitrogen-based fertilizer in sufficient quantities to achieve the highest possible crop yields without over-applying - a situation that could lead to serious environmental effects. In wheat, a critical factor comes down to timing in order to determine how efficiently plants will use nitrogen fertilizer. Current methods for determining the optimum timing of nitrogen fertilizer application can be costly, time consuming, and difficult.

To assist wheat growers, scientists at North Carolina State University recently developed a technique to properly time nitrogen fertilizer applications. The technique? Remote sensing - a relatively new technology to today's modern agriculture that uses aerial photography and satellite imagery.

In this 2000-2001 study, scientists used remote sensing in the form of infrared aerial photographs to determine when early nitrogen fertilizer applications were required. By relating the infrared reflectance of the crop canopy to wheat tiller density, the scientists were able to differentiate wheat fields that would benefit from early nitrogen fertilizer applications compared to wheat fields that would benefit from standard nitrogen fertilizer applications. They tested 978 field locations, representing a wide range of environmental and climatic conditions. The remote sensing technique was found to accurately time nitrogen fertilizer applications 86% of the time across all field locations. The results of this study are published in the January/February 2003 issue of Agronomy Journal.

Michael Flowers, project scientist, said, "This is one of the first applications of remote sensing technology for nitrogen management available to growers. With the ability to cover large areas in a quick and efficient manner, this remote sensing technique will assist growers in making difficult nitrogen management decisions that affect profitability and environmental stewardship."

These scientists at North Carolina State University and other institutions around the world are continuing to research remote sensing techniques to improve the efficiency of nitrogen fertilizer applications in crops. These techniques will allow growers to more efficiently apply nitrogen fertilizer, increase profitability, and avoid detrimental environmental effects.



Agronomy Journal, http://agron.scijournals.org is a peer-reviewed, international journal of agriculture and natural resource sciences published six times a year by the American Society of Agronomy (ASA). Agronomy Journal contains research papers on all aspects of crop and soil science including resident education, military land use and management, agroclimatology and agronomic modeling, extension education, environmental quality, international agronomy, agricultural research station management, and integrated agricultural systems.

The American Society of Agronomy (ASA), the Crop Science Society of America (CSSA), and the Soil Science Society of America (SSSA) are educational organizations helping their 10,000+ members advance the disciplines and practices of agronomy, crop and soil sciences by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.



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The above post is reprinted from materials provided by American Society Of Agronomy. Note: Materials may be edited for content and length.

Article source: Science Daily

A Case Study in Environmental GIS: Light Pollution Mapping

Marcus Hinds, a geospatial consultant, shares the results of his work with using remote sensing and methodologies from environmental GIS to better understand and provide solutions to mediate light pollution in the Greater Toronto Area in Canada.

Nathan Heazlewood in one of his recent blurbs urged us Geomatics practitioners to be proud of the Geospatial profession, in his article “take pride in the Geospatial Profession“. GIS and Geomatics are a large part of many environmental projects, because, let’s face it, environmental projects have to occur in time and space. That space is always located on the surface or beneath the earth, and persons responsible for the progress of the project need to know the specs of the project like what is happening, where it’s happening, why it’s happening and who is doing it. Every event is linked to the project in some way.

I’m no stranger to environmental GIS projects. Many of these (GIS projects) projects cross into other disciplines such as Energy, Finance, and Engineering and probably the most controversial of all, Politics.

Light Pollution Mapping in Toronto, Canada

One example of how interdisciplinary an environmental GIS project can become, is one that I recently worked on; the Light Pollution Initiative with the City of Toronto. The City was looking to reduce its lighting footprint and find ways of informing Greater Toronto Area (GTA) residents, about sources and effects of light pollution. Light pollution in this case is mainly classified, as any form of up-lighting and or over-lighting that emits unwanted light into the night sky, also known as sky glow. SKy-glow has a number of harmful and non-harmful effects, but the most popular has to be when light spreads to suburban and rural areas and drowns the night sky and stars. Environmental Heath Perspective Research has shown that star gazing and night sky observation is on a rapid decline in the younger generation, simply because we can’t see the night sky in the majority of our cities. Another effect is that deciduous trees have delayed adaption to season changes because of prolonged exposure to light. Wildlife like turtles, birds, fish, reptiles, and other insects show decreased reproduction due to higher levels of light in previously dark habitats. I didn’t even mention the increased risk of smog in urban areas, preceding periods of heavy light pollution. In us humans, light pollution has been linked to the cause of sleep deprivation in the short term, melatonin deficiency, increased risk of cancer (breast and prostate), obesity, and raises the probability of early-onset diabetes in the long term.


Because a project like is sensitive to so many variables, like the layout of power grid, culture of the city, socioeconomic classes, and urban design of the city; it was a very multidisciplinary feat, which required tactical thinking. The response needed to be tailored from principles from Urban Planning, Environmental Engineering, Architecture and Ecology. The fact that the end user was a broad, largely non technical audience also had to be factored in. As I got to working, I quickly realized that this is an onion. The more you look at it, the more layer you find. Before I knew, I had to think about Illumination Engineering, Power Generation and Energy Efficiency, due to the hundreds of megawatt hours in electricity being consumed by up-lighting and over-illumination, adding stress to an already stressed set of grid infrastructure. I also had to think about the health care system because, any ailments stemming from light pollution will add casualties to the health care system. I quickly noticed how broad (and valuable) environmental GIS really is.

My original thought of the project’s response, was to go about highlighting light pollution hotspots throughout the greater city area and compare it to data coming out the electricity provider. As suspected, the brightest areas on the maps, where the most energy intensive areas of the grid. The real challenge though, was to highlight light pollution at night, when all the base maps available are “of day”, then how do I communicate this? Well just bled the two came to mind, and that I did.

To find the light pollution hotspots, I got a Google base map and overlayed a geo-referenced satellite light pollution image of the city from NASA’s International Space Station (ISS). Areas of bright up lighting and sky glow around the city were obvious to the naked eye; but I wanted to show more. I applied lighting standards from the Illuminating Society of North America (IESNA), which meant that IESNA’s effective lighting series was now involved.

I used RP-8 for street and roadway lighting, RP-6 for sports and recreational lighting, RP-33 for outdoor lighting schemes. RP-2 for mercantile areas and RP-3 for schools and educational facilities. Each standard had prescribed lighting thresholds, which suggest efficient and appropriate light levels that should be used for each application. Each standard also discussed the type and quality of light suitable for each application. Now; only to find how much over the lighting threshold each point of sky glow on my map wa, and use this to estimate energy use figures.


I determined the areas brighter than the lighting threshold, through blending the geo-referenced base map and the NASA light pollution image together in Image J image processing software, and passing that image through filters. Image J is an open source Java based image processing software. The first image filter I used was the Gaussian High Pass filter for image sharpening the image, in order to highlight areas of bright light contrasted against dark areas. Then I applied a Gaussian Low Pass for smoothing the image and highlighting the contrast between bright pixels and dark pixels. Finally I added the nearest neighbor filter in order to generalize individual points of up-lighting, and spread the pixels showing sky glow evenly around each area of up-lighting. This method highlighted individual points in the GTA that were contributing to up-lighting, but I still needed to find the amount of light generated by each point of up-lighting and the value that each point stands above the lighting threshold set out in IESNA’s standards.

Since Image J does not have the capacity to calculate exact threshold, I had to find another open source software package that was easy to use and was Java based as Image J was. My rebuttal was Open Source Computer Vision, better known as Open CV image processing software. I used the blended image output from Image J, input that into Open CV and made some copies of it. This process called simple thresholding was applied in series. The first image was greyscaled in order to assign a value to each pixel in the image; the second image was used to classify pixel values and the third used to set a lower lighting threshold value. These three images were then overlayed pasted onto to each other and were made transparent in order to see the detail on all three images. This led to a pixel value being assigned to each pixel, and being able to determine the value of how much each pixel was over the defined threshold. This order of filtering was suggested by an Open CV technician and delineated light pollution areas around the GTA with high precision. Open CV is very well suited to working with environmental GIS and has a strong point in working with polygons in photo interpretation.

AERIAL IMAGE OF THE GREATER TORONTO AREA (GTA), SHOWING LIGHT POLLUTION HOTSPOTS IN WHITE LIGHT. MAJOR STREETS AND HIGHWAYS CAN CLEARLY BE IDENTIFIED.

In retrospect, I’ve seen a couple photometric surveys of cities in my time, and I must say that the data created from this project is simultaneous with photometric surveys. And the most intriguing part is that it all happened through remote sensing.

The outcome of this survey is ongoing, but there are a number of items in progress:

• The City releasing documents surrounding the use of decorative lighting and its contribution to the skyline, noting that this form of lighting should not only be efficient and sustainable and should comprise LED’s, but should be turned off during migration periods for migratory birds. See Page 60 of Tall Building Design Guidelines (link:http://goo.gl/ddANm0)
• Many condo developers are now turning decorative lighting off at 11pm in the downtown core to facilitate light pollution standards and migratory bird guidelines set out by FLAP on the Flap Website (link:http://www.flap.org/)
• Discussion and literature has been released and in circulation for sometime, evaluating the efficiency of buildings that use glass as the main material in the building facade. Glass facades not only cause the building to be more energy intensive but also pose a hazard to birds, where they usually become disorientated and collide with the building, inflicting serous injuries and death. There have also been many cases of glass falling from these buildings in many Canadian cities. Building scientist Ted Kesik, a prominent building scientist based in Toronto, has estimated that condo pricing and maintenance fees to skyrocket in the next decade, simply because of the use of glass. The Condo Conundrum 
• Discussion surrounding implementing guidelines for the GTA to implement full cut off/fully shielded light fixtures for outdoor lighting, as some parts of Ottawa have done. See the Report to the Planning & Environmental Committee submitted by Deputy City Manager Planning, Transit and Environment, City of Ottawa

References: Skyglow/Light Pollution – NASA

Source

The EnMAP Spaceborne Imaging Spectroscopy Mission for Earth Observation

Journal Article by: Luis Guanter, Hermann Kaufmann, Karl Segl, Saskia Foerster, Christian Rogass, Sabine Chabrillat, Theres Kuester, André Hollstein, Godela Rossner, Christian Chlebek, Christoph Straif, Sebastian Fischer, Stefanie Schrader, Tobias Storch, Uta Heiden, Andreas Mueller, Martin Bachmann, Helmut Mühle, Rupert Müller, Martin Habermeyer, Andreas Ohndorf, Joachim Hill, Henning Buddenbaum, Patrick Hostert, Sebastian van der Linden, Pedro J. Leitão, Andreas Rabe, Roland Doerffer, Hajo Krasemann, Hongyan Xi, Wolfram Mauser, Tobias Hank, Matthias Locherer, Michael Rast, Karl Staenz and Bernhard Sang

Abstract

Imaging spectroscopy, also known as hyperspectral remote sensing, is based on the characterization of Earth surface materials and processes through spectrally-resolved measurements of the light interacting with matter. The potential of imaging spectroscopy for Earth remote sensing has been demonstrated since the 1980s. However, most of the developments and applications in imaging spectroscopy have largely relied on airborne spectrometers, as the amount and quality of space-based imaging spectroscopy data remain relatively low to date. The upcoming Environmental Mapping and Analysis Program (EnMAP) German imaging spectroscopy mission is intended to fill this gap. An overview of the main characteristics and current status of the mission is provided in this contribution. The core payload of EnMAP consists of a dual-spectrometer instrument measuring in the optical spectral range between 420 and 2450 nm with a spectral sampling distance varying between 5 and 12 nm and a reference signal-to-noise ratio of 400:1 in the visible and near-infrared and 180:1 in the shortwave-infrared parts of the spectrum. EnMAP images will cover a 30 km-wide area in the across-track direction with a ground sampling distance of 30 m. An across-track tilted observation capability will enable a target revisit time of up to four days at the Equator and better at high latitudes. EnMAP will contribute to the development and exploitation of spaceborne imaging spectroscopy applications by making high-quality data freely available to scientific users worldwide.

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

For full text, follow the link here.