Satellite images monitor vegetation response in Wyoming rangelands

Article originally published in Reflections a publication of the UW College of Agriculture and Natural Resources (Publication date: June 2012; pages 26-29)

Access the issue online at: http://www.uwyo.edu/uwexpstn/publications/reflections/2012/reflections-2012-web.pdf (5.5 MB)


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Satellite images monitor vegetation response in Wyoming rangelands

Students capitalize on no-cost Landsat images to map rangeland vegetation

Rangeland vegetation responds to both environmental variations (e.g., drought, precipitation) and human interventions (e.g., grazing management). These responses can be rapid (e.g., wildfire), seasonal (e.g., grazing) or slow (e.g., invasion of non-native species).

Ranchers, land managers, and planners need periodic information about where and how changes are occurring. Collecting change information through field surveys is expensive and time-consuming and often does not provide a complete picture because only a portion of the area is sampled.

Monitor and Map Vegetation Responses

Remotely sensed images can be used for monitoring and mapping vegetation response to environmental and human influences. Since information derived from remotely sensed data is not always similar to data collected in the field, researchers have developed indices and metrics that can provide valuable insights for monitoring and mapping natural resources. With the availability of more types of remotely sensed data, new indices and metrics are also being developed for monitoring vegetation in rangelands and elsewhere.

University of Wyoming students enrolled in the Remote Sensing for Agricultural Management course are trained in the use of remotely sensed data for monitoring and mapping vegetation in rangelands and forests. In addition to learning remote sensing concepts, students are required to complete an inquiry-based research project of their choice involving use of remotely sensed data for answering questions pertaining to natural resource management.

Images Cover 100 x 100 miles

Most students use Landsat data provided by the US Geological Survey (USGS) through the GloVis website for monitoring or mapping vegetation response in rangelands, forests, and agricultural fields. Each image (referred to as a scene) covers roughly 100 miles x 100 miles on the ground and contains information in the visible and infrared regions of the electromagnetic spectrum. Landsat images can be used for mapping present and past (since 1972) conditions of rangelands, forests, crop fields, lakes, and other earth surface features (Figure 1).

		Figure 1: Landsat images acquired in 1999, 2002, 2005, and 2011 for an area adjacent to Keyhole Reservoir near Moorcroft demonstrate their utility for monitoring changes in natural resources such as vegetation rangeland and riparian zones and water. Intensity of green color can be associated with high (bright) and low (dark) vigor. Vegetation growth is low (few areas in green) during drought years (2002 and 2005) and relatively higher in normal and wet years (1999 and 2011). The surface area of the reservoir also fluctuates between these years as a result of natural and human influences.

Although Landsat satellites have collected data since 1972, their widespread use was somewhat limited because of the high cost associated with acquiring those images. However, since December 2008, USGS is providing all Landsat images at no-cost to users, which has generated an unprecedented opportunity for students enrolled in this class.

Students interested in rangeland management have obtained numerous Landsat images for monitoring vegetation growth and mapping changes in vegetation conditions over time. Almost all students selected ranches either their parents owned or where the students worked in the summer.

Monitors Rangeland Allotments

Selecting familiar study sites provides a unique opportunity for evaluating the utility of Landsat image information. Clint Beiermann, an agroecology major, analyzed vegetation responses in three rangeland allotments where he worked one summer. Analyses of Landsat images from May 17, June 2, June 18, and July 4, 2007, (Figure 2) showed different vegetation growth rates between allotments. Grasses and forbs grew early in the season in one type of allotment while growth was delayed in another. During the end of the growing season, differences between allotments were minimal. He concluded Landsat images can be used for routine monitoring of rangeland vegetation.

		Figure 2: Landsat images acquired from May through July 2007 were used for monitoring vegetation (green) growth in allotments under different management regimes. Water in the ponds appears black, and allotment boundaries (white) were superimposed on the image. Clouds and their shadows (bottom left of July 7 image below) could limit the use of Landsat data.

Studies Grazing Effects

Having image data for the entire study area enabled identification of patterns and anomalies (areas of high, medium, and low growth). Brandon Greet, also an agroecology major, monitored the grazing impact on a ranch in the Big Horn Mountains using Landsat images from June 29, August 25, and September 17, 2008. He categorized vegetation in this rangeland into high, medium, and low vigor  and found the area of the low-vigor vegetation class increased during the growing season. Further, he noticed vegetation re-growth in September in some of the areas classified as bare ground in the August image. He generated maps that showed where these changes have occurred, which could help ranchers improve grazing by focusing cattle on under-utilized areas.

Most students (and owners of the ranches where they worked) had a general sense of the changes in vegetation composition and patterns. Visualizing those changes in Landsat images acquired several years apart sheds new light on the types and magnitude.

Researches Forage Availability

Matthew Allshouse (a rangeland and ecology management major) monitored forage availability and riparian vegetation at a ranch near Laramie (Figure 3). Over the last several years, this ranch shifted from intensive grazing to multiple-objective management. Ranch owners have implemented a rest rotation grazing regime, fenced off riparian areas, and also built a reservoir to improve riparian habitat. Allshouse obtained a Landsat image from 2001 to establish baseline vegetation conditions and used the 2006 and 2011 images for monitoring and mapping how vegetation responded to the changes in management practices.

Students gained experience processing remotely sensed data and extracting information pertinent to their research questions by working independently on
their projects. They evaluated several vegetation indices derived from Landsat
data and determined the suitability for monitoring and mapping rangeland vegetation. Over the past few years, students enrolled in this course have used Landsat and other remotely sensed data for monitoring natural resources in Wyoming and other states. Several students have also presented their research work at the Wyoming Undergraduate Research Days.

As more and more students take advantage of the no-cost Landsat data, findings from their research projects may benefit the community by providing insights about the utility and limitations of Landsat data for natural resource monitoring in Wyoming and elsewhere.

UW Students Research Value of Satellite Images for Monitoring Wyoming Resources

Source: UW Extension Service's press release
By: Steven L. Miller, Senior Editor
Date: 21 May 2012


Students at the University of Wyoming found that aspen had budded earlier in a drought year, and that surface area estimates from satellite images matched well with corresponding water levels in Woodruff Narrows Reservoir near Evanston. Other students used information derived from remotely sensed images to monitor crop growth on a southeast Wyoming wheat farm and the effects of the 2004 Basin Draw fire in northeast Wyoming. The research taught students how to use satellite images and its effectiveness.

Every spring semester, three to five students -- in the Department of Ecosystem Science and Management in the UW College of Agriculture and Natural Resources -- conduct research using remotely sensed data on a topic of their interest, says Ramesh Sivanpillai, research scientist in the Wyoming Geographic Information Science Center. He teaches the college's digital image processing for natural resources management course.

"Most of these students select the farms or ranches owned by family members or forests and public land they have worked on during summer months," he says. "Familiarity about their study areas provides them a unique advantage when analyzing and interpreting satellite images, and for conveying the findings of their study to the landowners or agencies."

Matthew Thoman of Riverton worked on a dryland winter wheat farm east of Cheyenne and was familiar with the fields. By processing Landsat images from the growing seasons of 2007 and 2009, he found growth variations within fields -- despite higher soil moisture levels in 2009 than 2007.

He will share the information with the producer, who could devise plans to correct the deficiencies, Sivanpillai says.

Brandt Schiche of Buffalo used Landsat images to glean information about surface area changes on Woodruff Narrows Reservoir. Water from the reservoir is used for irrigation, recreation and industry, and is shared between Utah and Wyoming.

"He found a significant relationship between the surface area estimates derived from Landsat images and the corresponding water levels in the reservoir," Sivanpillai says.

Jason Pindell of Wheatland used MODIS (Moderate Resolution Imaging Spectroradiometer) data to assess differences in the growing pattern of aspen stands in the Medicine Bow National Forest. His research showed aspen put out leaves relatively earlier (bud-burst) in a drought year (2002) in comparison to the bud-burst in a normal year (2009).

Orin Hutchinson of Newcastle (pictured above) had worked with the U.S. Forest Service managing wildfires. He evaluated indices derived from Landsat images that highlighted burned (immediately) and revegetated (few years later) areas after the 2004 Basin Draw fire northwest of Aladdin in Crook County. The fire burned more than 4,500 acres in three days, but its impact and severity varied throughout the landscape.

"His results pointed out that burn severity index values were in good agreement with the data collected in the field," Sivanpillai says. "However, extraneous factors, such as precipitation and management practices, influenced the vegetation regrowth, limiting the effectiveness of satellite data for monitoring regrowth after several years."

Students presented their findings during UW's recent Undergraduate Research Day.

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Sixth graders learn the value of satellite images for highlighting changes in urban areas and water bodies

Fifty-one students at Laramie Junior High School (LJHS) saw how satellite images collected since the 1970s can be used to monitor changes in cities and water bodies such as rivers and lakes. In Jared Long’s social science class, students are learning about urban growth and changes in water bodies caused by natural processes and human actions. In particular, they were comparing these changes in developed, developing and under-developed countries.

WyomingView coordinator Ramesh Sivanpillai described how satellites and aircraft are used to acquire these birds-eye images.  Using images acquired by Landsat and TERRA satellites, he demonstrated the growth of cities in the U.S., Mexico, Uganda and middle-East. These images were acquired 10-30 years apart. Students saw how cropland and forests were converted to urban areas to accommodate urban growth. Students also saw the video created by NASA that showed the yearly expansion of Las Vegas from 1974 – 2011. This video highlighted the mushrooming of Las Vegas and the addition of subdivisions, golf-courses and commercial areas. Satellite images also showed the new dams and reservoirs, changes in their water storage over time, and impacts of catastrophic events, such as flooding, can have on cities.

“Our students greatly benefited from this presentation” said Jared Long, social science teacher LJHS. “The presentation had been tailored to topics that have been addressed in our class over the course of the year, specifically how water bodies and urban areas change over time … our students' knowledge and engagement with these topics increased substantially.”

This outreach activity was conducted as part of AmericaView’s Earth Observation Day activities aimed at introducing teachers and students to remote sensing science and applications.

Introducing Laramie Junior High School Students to Remote Sensing Concepts and Applications

One hundred and fourteen students in Ron Whitman’s eight grade physical and seventh grade biological sciences classes (three class periods each on April 4^th and 5^th, 2012) learned how remotely sensed images are acquired in different regions of the electromagnetic radiation (EMR) and their uses for monitoring earth surface features such as trees, crops, bare ground, water, roads, buildings, etc.

WyomingView coordinator Ramesh Sivanpillai described the differences in the interaction of earth surface features with EMR, and how those interactions result in their appearances or colors.  Students learned the uses of images collected by satellites and airplanes for monitoring the effects of beetle attacks on pine trees, deforestation, crop growth, and changes in the surface areas of lakes and reservoirs.  Mr. Whitman commented that the presentation helped “students understand the use of different electromagnetic waves for practical applications.”

In the lab, students working in teams used ALTA™ Spectrometers to measure spectral reflectance in 10 different regions of EMR.  Next, they calculated percent reflectance values, which were then plotted against wavelength to generate the spectral signature for each leaf.  

Analyses of these signatures led the students to conclude that the spectral signature of each leaf was distinct.  

Hands-on lab component for measuring and calculating “percent reflectance of the four types of leaves at different wavelengths, actively engaged the students the entire lab time” Mr. Whitman said.  Sivanpillai explained the differences in the spectral signatures of different earth surface features and remote sensing scientists rely on these signatures for mapping those features.

This educational outreach activity was conducted as part of AmericaView’s Earth Observation Day activities aimed at introducing teachers and students to remote sensing science and applications.

2010 FLOODING: LARAMIE, WYO.

The Laramie River topped its banks in June 2010 Albany County as a result of snowmelt, flooding several streets and parks in the City of Laramie (more information on Laramie Boomerang). City’s Greenbelt and several properties were severely impacted as a result of this flooding event. Albany County Emergency Management personnel had to divert water upstream of Laramie to protect properties in the city.

Data collected by Thematic Mapper on the Landsat 5 satellite on 21 June 2010 (above) shows the extent of flooding (water appears black in color). Laramie River appears as a narrow, meandering feature in the 29 June 2007 (normal flow) image also acquired by Landsat 5.

Data collected by Landsat and other moderate resolution satellites can be used to gain insights about past flooding patterns and devise plans to minimize the impacts of future floods.

Landsat satellites are jointly managed by USGS (http://landsat.usgs.gov/) and NASA (http://landsat.gsfc.nasa.gov/).

URBAN GROWTH: CHEYENNE, WYO.

In 1867, when it was granted a permanent city charter by the Dakota Territory legislature the City of Cheyenne was home to approximately 600 people. In 2010 its population was nearly 60,000 a 100-fold increase.

Data collected by Thematic Mapper sensor (on the Landsat 5 satellite) in 1985 (1980 Pop: 47,283) and 2011 (2010 Pop: 59,466) shows Cheyenne’s growth over 26 years. Highways I-80 and I-25 cross each other in southwest Cheyenne. Most of the growth has occurred in the northern and northeastern parts of the city. Green tones correspond to vegetation such as trees, shrubs, grasses, and croplands.

Ongoing construction activities are visible in the eastern side (County Fairgrounds) and southwest side (industrial complex) of the 2011 image. Change detection using imagery can help us understand the past and better plan for the future.

The Landsat 5 satellite was launched by NASA and operated by USGS for monitoring earth’s surface.

Sources: USGS (http://landsat.usgs.gov/) and Wyoming's Economic Analysis Division (http://eadiv.state.wy.us/demog_data/cntycity_hist.htm)

Using satellite images 5th and 6th grade students in UW Lab School learn about human impact on environment

With the help of satellite images fifth and sixth grade students at Mr. Tim Blum’s geography class (photo above) at the UW Lab School (31 January 2011) got a birds-eye view of how humans have impacted or modified their environments.  Images acquired by satellites decades apart showed cleared forests, irrigated crop fields in the middle of the deserts, altered landscapes (new roads and water bodies), and urban growth. 

As part of the Earth Observation Day (EOD) activities, WyomingView coordinator Ramesh Sivanpillai described the utility of images acquired by satellites are useful for monitoring changes on earth’s surface.   

For example, Landsat images acquired in 2000 (bottom left) and 2009 (bottom right) shows the newly constructed roads, drilling pads, and ponds for an area within the Powder River Basin.

The goal of EOD activities is to introduce teachers and students to remote sensing science and technology and is promoted by AmericaView.  Sivanpillai works with individual teachers in Laramie-area schools and develops remote sensing course materials that relate to the topics taught to students.

Blum and his student teachers introduced students to the human impact on the environment.  The remote sensing “presentation fit with our curriculum and the students were captivated,” Blum commented.  “Your presentation certainly made an impression on our students because the information you provided was referenced in several discussions that occurred later in our unit.”  Tailoring materials to individual class needs increases student engagement and learning.

Laramie Junior High School Students learn about Remote Sensing Science and Career Opportunities

Infrared images acquired by Landsat
shows active fires "through-the-smoke".
Images acquired in human visible
region will be "covered with smoke".

One hundred and two students in Mr. Ron Whitman’s eighth (physical sciences) and seventh (biological sciences) grade classes (three class periods each on April 5th and 6th 2011) learned how remotely sensed data collected in different regions of the electromagnetic radiation (EMR) are used for looking at changes on the surface of the earth.

WyomingView coordinator Ramesh Sivanpillai showed satellite and aerial images collected in the visible region (for human beings) and beyond (infrared) and their utility for monitoring the surface of earth and the changes occurring in it.  Examples included monitoring water quality, deforestation, and wildfire damages (see Landsat images acquired during and after a wildfire event in Wyoming).

The post-fire infrared images acquired
by Landsat shows both the extent
and severity of the wildfire. US
Forest Service and other federal agencies
use Landsat and similar images for
assessing burn severity classes.

“Identifying the practical applications of remote sensing and how physical science concepts are used in remote sensing has been very beneficial to my class” commented Mr. Whitman.“Using different electromagnetic waves other than visible light to make observations is always intriguing to my class” he added.


Sivanpillai also discussed career opportunities in remote sensing and how students can academically prepare for them.  “Many students see the occupation opportunities involved with this field, especially the potential to travel and view many other geographic areas” said Mr. Whitman.  “Having professionals visit my classroom or going to their occupation site always motivates my students to try a little harder in my academically rigorous class”.

This educational outreach activity was conducted on April 5th and 6th (6 individual talks) as part of AmericaView’s Earth Observation Day activities aimed at introducing teachers and students to remote sensing science and applications.

Satellite Images show how Humans Impact their Environment: Earth Observation Day Event at Slade Elementary School

Sixth graders at Slade Elementary School (SES) saw how remotely sensed images collected by satellites orbiting the earth can be used for monitoring how humans are impacting their environment.  Students in Mr. Jared Long's and Mr. Andy Pannell's classes were learning about how humans are modifying their environment through their activities.

Mr. Pannell (left) and Mr. Long (right), 6th grade teachers
at Slade Elementary School, Laramie Wyoming.

Using satellite images acquired at different times, WyomingView coordinator Ramesh Sivanpillai highlighted human-made changes in different parts of the world.

For example, Landsat images showed how agriculture activities have expanded in Namibia, deforestation in Brazil and Rwanda, urban growth in Pearl River Delta (China), and Dubai, and shrimp farming in Ecuador.

Sivanpillai described the long history of remote sensing and the different platforms (pigeons, balloons, airplanes and satellites) that were used for collecting images in the visible and invisible (infrared) parts of the electromagnetic spectrum.

Student responses were "Learned a lot about earth (Zach)", "Different views of leaves! Really cool (Brianna)", "Change over time on earth very interesting (Liz)", "Wildfire pictures (Tamer)", and "very interesting, informative (Phoenix)", when asked "what stuck out" most from this presentation.  Mr. Long commented that "students and I really enjoyed" the presentation.

This outreach activity was conducted on February 22, 2011 as part of AmericaView’s Earth Observation Day activities aimed at introducing teachers and students to remote sensing science and applications.

WyomingView interns present their research findings in the 2010 GIS in the Rockies Conference

WyomingView interns (spring 2010 semester) Paul Arendt and William (Bill) Gray presented their research findings in the 23rd annual GIS in the Rockies Conference in Loveland, CO.

Using Landsat images Paul Arendt (BA Geography) analyzed the spectral reflectance patterns of areas impacted by the Mountain pine beetle in the Medicine Bow National Forest, Wyoming.  He combined Landsat observations with aerial survey data collected by the US Forest Service to identify differences in the reflectance patterns of beetle infected (n=77) and non-infected (n=50) areas. He calculated Normalized Difference Vegetation Index (NDVI) and Tasseled Cap Wetness Index for these sites and found that both indices had lower values at affected sites and these differences were statistically significant (p < 0.01). Within the 77 beetle infected sites, the mean NDVI and Tasseled Cap wetness values were higher (p < 0.01) in the patchy lower forest (< 2567 m) in comparison to the subalpine lodgepole pine (>2568 m) forest.  Describing the value of this research, Paul commented "...this project served as an excellent introduction to the process of scientific research".

Bill Gray (MA Planning) used Landsat images acquired from 1984 through 2009 to map changes in the surface area of Ocean Lake in Freemont County, Wyoming. Using images acquired in spring and fall for 27 years, he mapped changes in the surface area and compared the within- and between-year variations.  His findings revealed that the lake's surface area in spring (2442 hectares) was less in comparison to the surface area in fall or autumn (2457 hectares).  The overall area showed a declining trend from 2536 ha (fall 1986) to 2392 ha (fall 2009).

Both studies were possible due to the availability of no-cost Landsat data.  Prior to the no-cost Landsat data era, purchasing 54 images that Bill Gray used in his study, would have cost him US$ 35,000 which would be beyond the reach of any graduate student.  "A unique aspect of this study is that it offers the end-user a technique to use the free archive of LandSat images in a time series for analysis..." said Bill Gray.

Every semester WyomingView offers internships to UW undergraduate and graduate students to work on projects that use remotely sensed data for addressing natural resource management issues in Wyoming.

Enhanced learning through student selected agricultural remote sensing projects

Article originally published in Reflections a publication of the UW College of Agriculture and Natural Resources (Publication date: June 2010; pages 56-58)

Access the issue online at: http://www.uwyo.edu/uwexpstn/publications/reflections/2010/reflections_2010.pdf (5.3 MB)

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Enhanced learning through student selected agricultural remote sensing projects

Students utilize high-tech opportunities to examine Wyoming crop, ranch, and forest areas 

Carla Grefroh of Douglas, WY compares vegetation on her family’s ranch during drought and wet years

Images from earth observation satellites provide valuable information for students and researchers interested in monitoring natural resources. These remotely sensed images provide a bird-eye’s view of the earth’s surface and enable monitoring of rangelands, shrublands, and forests.

Many remote sensing satellites collect images at regular intervals, giving researchers an opportunity to monitor changes on the earth’s surface.  They can also be used to characterize variability in vegetation conditions within an agricultural field, ranch, or forest.  Vegetation growth stage (emergent vs. full canopy) and condition (healthy vs. stressed) can be determined by examining reflected infrared light, which is measured by many remote sensing satellites.

In general, remotely sensed images contain a wealth of information about the earth’s surface and are valuable for a wide range of users.

Remotely sensed satellites divide the earth surface into a uniform grid comprised of pixels and record the amount of reflected visible and infrared light coming to the satellite from each pixel.  Analysts examine the pattern of reflected light across a range of wavelengths to extract information about places in an image.  For example, a farmer can monitor changes in crop growth during the growing season using a series of Landsat images (Box 1).  A rancher can map forage conditions on a ranch and also identify areas of poor or no vegetation growth.

Box 1: Landsat images

Landsat images have been collected by a series of remote sensing satellites operated by the U.S. government since early 1970s (http://landsat.usgs.gov) and represent an extensive civilian archive in terms of duration (more than 36 years) and geographic coverage. Landsat collects a new image every 16 days for every place on earth.  Each image covers a relatively large geographic area (approximately 90 miles x 90 miles). Landsat records information from the visible region and the infrared regions of the spectrum, which is useful for monitoring vegetation condition and for a wide variety of other applications. Countless studies have demonstrated the value of Landsat data for monitoring changes in croplands, rangelands and forests. Landsat images are useful when monitoring rangelands and croplands through conventional field surveys is not feasible due to cost or access issues.

Increasing student employment potential

Changes introduced by natural disturbances, such as wildfires and droughts, and anthropogenic activities, such as land conversion, are creating new applications of remotely sensed imagery.  Because the imagery is so valuable, several countries have launched remotely sensed satellites to collect earth observation data.  In the U.S., federal and state government agencies, as well as private companies, are launching and operating remote sensing satellites. Students who learn image processing and interpretation skills as part of their academic training often increase their employment potential.

Ag remote sensing projects

UW students are learning to implement many of the applications described above in the Applied Remote Sensing for Agricultural Management (BOT/RNEW 4130/5130 and AECL4130) course.  One requirement of this course is that students complete a class project using imagery to answer questions about a real-world agricultural issue. For example, some students use images of their parent’s farm or ranch to obtain a better understanding of crop growth patterns by comparing the images to conditions observed on the ground.

Students associate areas of poor growth (often characterized by low infrared reflectance) identified in the image to problems such as soil alkalinity or poor water drainage.  Similarly, several students obtained images acquired in normal and drought years for rangelands and mapped changes in vegetation condition.  Students enhanced their learning experience by selecting images for areas of interest to them rather than working on pre-defined laboratory exercises.

Mapping crop growth in the Big Horn River Basin

Garret Klein and Laramie Wiginton (rangeland ecology majors), Chris Heil (agroecology major) and Travis Yeik (geography major) used Landsat images for monitoring crop growth in agricultural fields in Freemont and Washakie counties.

Klein and Wiginton mapped crop growth by computing a vegetation index derived from the amount of reflected red and infrared light.  Based on their research, they concluded Landsat images could be used to accurately identify areas of poor and medium growth for different crops; however, they noticed some weed infested areas also had high infrared reflectance due to dense canopy, thereby reducing the utility of Landsat data under these circumstances.

Yeik analyzed growth patterns in sugar beets and alfalfa crops in Worland using Landsat images acquired from 2006, 2007, and 2008.  This multi-year analysis of crop growth patterns was necessary for identifying areas of poor and high growth and for devising appropriate management plans to help improve crop yields.

Assessing wildfire damage to forest vegetation

Using Landsat images, Cody Tully estimated wildfire burn severity of a fire in Medicine Bow National Forest, Brice Stanton and Adam Stephens for a fire in the Black Hills National Forest, and Anne Morabito for a fire in Southern California. Stanton and Tully worked on firefighting teams and had firsthand knowledge of the impacts of fire on forest vegetation.  This knowledge was valuable for interpreting the information derived from Landsat images about burn severity patterns.

Cody Tully of Sinclair, WY helped fight the 2006 Isabelle Fire that burned near
Lake Owen in Southeast Wyoming. He is examining satellite images of the burn

Tully fought the 2006 Isabelle Fire that burned 1 mile south of Lake Owen in southeast Wyoming.  Burn Ratio Indices derived from the Landsat images acquired before and after the wildfire enabled him to distinctly classify the burned areas and also group them by severity classes.

Using the same method, Morabito (a California native) generated burn severity maps depicting various levels of damage caused by the Station Fire near Los Angeles in Southern California during August 2009.   Methodology used by these students is identical to the methods used by federal and state land management agencies tasked with fighting wildfires and monitoring vegetation establishment in burned areas.

Monitoring Wyoming Rangelands

Most students used Landsat images for monitoring rangelands throughout Wyoming.  Students compared vegetation condition during drought years to normal years and estimated the differences in spectral reflectance in different regions of the electromagnetic spectrum.  For example, Carla Gefroh (rangeland ecology major) compared the vegetation condition for her family ranch using images acquired in June 2002 and 2009, representing drought and wet years, respectively.  Landsat images highlighted changes in vegetation condition during the drought and wet years.

Monitoring vegetation response to drought was one topic in the class.  Other projects included monitoring vegetation condition in a growing season for estimating forage availability and areas of overgrazing.  The synoptic view provided by Landsat images was invaluable for gaining insights about vegetation condition in rangelands, and repeat coverage helped students to map those changes.

USGS Offers Landsat Satellite Images for Free

In December 2008, the entire Landsat satellite image archive was made available for free through the U.S. Geological Survey.  Previously, images had to be purchased (terrain corrected images could cost as much as $800) unless they were archived by programs like AmericaView (http://www.americaview.org) or on dedicated public Web sites like that of the Global Land Cover Facility (http://glcf.umiacs.umd.edu).

The recent availability of no-cost Landsat images has created opportunities and enhanced learning experiences for students. When fewer no-cost Landsat images were available, students had to modify the scope of their projects to match data availability.  Now, students can download any number of images for anywhere on earth.

UW students enrolled in the Applied Remote Sensing for Agricultural Management course are taking advantage of this valuable opportunity and are using these images for monitoring and mapping Wyoming croplands, rangelands, and forests.