Monday, February 8, 2016

Topographic Solar Radiation Models for GIS

Solar radiation is an important natural phenomenon that impacts many aspects of the environment and human life. The ability to model this radiation accurately is crucial in numerous fields, including agriculture, ecology, engineering, and forestry. 

In their article, Dubayah and Rich seek to understand the performance of GIS when used as a tool to model solar radiation on the Earth’s surface. Several different factors influence solar radiation at a particular point on the Earth: topography, illumination angle, obstruction of the sky by nearby terrain, and reflectance of radiation by surrounding terrain. Dubayah and Rich argue that all of these factors can be modeled in a GIS to create a “sophisticated” solar radiation model. In their research, they evaluate two different GIS models currently used by scientists: ATM and SOLARFLUX. ATM is a raster-based model focused on atmospheric radiation that can “generate detailed topoclimatologies for large areas at arbitrary time intervals.” SOLARFLUX uses input of elevation, latitude, and atmospheric conditions to calculate the level and duration of direct radiation to each point.

Both of these models are useful, especially when used in tandem, but Dubayah and Rich emphasize there are still many problems to be solved if GIS is to improve its radiation modeling capabilities. These problems include better integration with other programs, the need for basic solar radiation modeling in new versions of software, and the capability to model clouds (which greatly affect radiation). They also comment on the problem of significant errors in public digital elevation data. As calculations based on this data are performed, this error propagates, potentially leading to inaccurate conclusions. Despite these future challenges, Dubayah and Rich conclude that GIS has the potential to “provide the ideal modeling environment for … solar radiation models.”

Dubayah, R., & Rich, P. M. (1995). Topographic solar radiation models for GIS. International Journal of Geographical Information Systems, 9(4), 405-419.

I have acted with honesty and integrity in producing this work and am unaware of anyone who has not. 
Simone Yoxall

GIS Application for Soil Erosion Assessment

The study focused on assessing quantitatively the soil erosion using the Revised Universal Soil Loss Eq. 2 (RUSLE2)  model with the help of remote sensing and GIS in a subwatershed in the catchment of Krishnagiri reservoir in Tamil Nadu, India. “Land degradation from water-induced soil erosion is a serious problem in India and thus it forms an important social and economic problem.” (p.83)

Soil erosion affects soil fertility and crop yields by removing organic matter from the soil and breaking down the soil structure. It is a “three-stage process: detachment,transport and deposition. The factors that influence the rate of soil erosion include rainfall, runoff, slope, land cover and the presence or absence of conservation strategies.” (p.84) Thus, the study estimated erosion for each hill slope unit by considering “intensity of rainfall, type of soil, land use classification, and the existing soil conservation practices.” (p.84)

“A data base was created with all the subfactor values for the hill slope units. Incorporation of remote sensing technique and Geographic Information System (GIS) made the spatial analysis of the study more reliable and accurate. The annual average soil erosion rate is estimated as 25 t/ha/year, which is on a higher range.” (p. 83)
Four topographic maps of the region were scanned to cover the whole subwatershed  and then georeferenced. “The subwatershed boundary was delineated and digitized. The drainage patterns, contour lines, roads, towns etc. were identified and digitized to create different thematic layers. Based on the order of the streams and terrain characteristics the whole area is subdivided into small hill slope units. The number of hill slope units chosen is 48 and is shown in Fig. 2.” (p. 94)

After aggregating the different factors such as soil erodibility and slope length and steepness the researchers estimated and annual average erosity of 81.6 (MJ mm)/(ha h) for the Veppanapalli subwatershed during the year 2003. (p. 99) The map below shows different soil loss ranges in sub-watershed divided into the 48 hill slope units.

With the help of erosion models and GIS excessive soil loss can be predicted. Therefore better conservation strategies can be undertaken to prevent it benefiting  in this case Tamil Nadu and India as a whole socially and economically.

Source: Ismail, J., & Ravichandran, S. (2008). RUSLE2 model application for soil erosion assessment using remote sensing and GIS. Water resources management, 22(1), 83-102.

I have acted with honesty and integrity in producing this work and am unaware of anyone who has not. -Ilka Vega

Mice Outbreak in Austrailia and Solutions

Recently in Australia a mice outbreak has disrupted crop production and infested farmlands. Southern Australia, as shown in the figure below, is the most affected region from the outbreak. With costs reaching substantial balances of upwards to three hundred million dollars in losses of agricultural production, researchers were able to compare the map of both the region of the outbreak of mice to a map showing the most prominent crop grown in that region to conclude which type of crop the mice are most attracted to. In the Southeastern region of Australia, grain crops were found to be the most abundantly grown therefore reaching conclusions that the mice are most attracted to the grain. As well as the specific type of crop attracting these mice, researchers have also analyzed climate maps of the Southeastern region to find that as the climate grows hotter and hotter, the mice population grows more. At the same time of the most severe outbreak, climate maps proved that higher temperature and record-low rainfall years prompted the outbreak for mice cannot survive as well in cold, damp climates. Through this evidence, researchers can promote artificial climates for these fields of infested crops.
O'Rourke, J. "Farmers' bane returns". The Sydney Morning Herald- Environment. October 2011. p. NA
I have acted with honesty and integrity in producing this
 work and am unaware of anyone who has not- Austyn Laird

Topography-based Analysis of Hurricane Katrina Inundation of New Orleans

Lidar is a remote sensing technology that collects detailed, high-precision measurements of land elevation. Recently, the U.S. Geological Survey has collected election data into the National Elevation Dataset. The elevation measurements were already added to NED before hurricane Katrina struck, so they were able to have the data available immediately after hurricane Katrina.
The figure above shows the elevation data collected using Lidar. This representation shows Lake Pontchartrain and the Mississippi River to be higher than the land in the middle of the city, which is referring to the bowl shape of New Orleans. Often Lidar incorrectly measures areas over water, so the elevation of the water surface is inferred with areas surrounding it. 

I have acted with honesty and integrity in producing this work and am unaware of anyone who has not. Nataley Ford

Gesch, D. (2005). Topography-based analysis of Hurricane Katrina inundation of New Orleans. Science and the Storms: the USGS Response to the Hurricanes of, 53-56.

Locating farmers’ markets with an incorporation of spatio-temporal variation

With an increase in the amount of people that are health conscious or “green”, more of the population are looking for high-quality and environment-friendly foods. This has lead to a surge of consumers’ interest for locally grown food and farmers’ markets. But, many small scale growers are still unable to attend farmers’ markets with time constraints and trivial travel. Using GIS and spatio-temporal variation the authors of the journal mapped out high population areas, and attempted to evenly space out farmers’ markets in order to find a more efficient way to support local grown foods, while also limiting travel distances.

Using GIS to Predict Emergency Situations

Place and health are not “fixed realities but are situated and socially produced in particular contexts. What this means is that GIS are being used in public health studies to model where people live and the environments they experience through their day to day lives. With this information, it can be mapped out where the higher health risk areas are and where emergency services are needed. Understanding issues ranging from medical epidemiology to health care access requires a comprehensive understanding of their spatial distribution as well as the physical, social, and psychological environments with which they occur in. Researchers, public health professionals, and policymakers use GIS to better understand the geographic relationships that affect health outcomes, public health risks, disease transmission, access to health care, and other public health concerns.

This study presents a methodology for performing health emergency assessments and generating hazard maps that show areas that are potentially at high risk for health emergencies. The goal of collected this data is to take action on the planning, management, and prevention levels of emergency situations. Using neural networks and GIS theory researchers and analysts are able to create intelligence. This intelligence is then used to predict the mathematical patterns regarding the locations of emergency events. The power of GIS comes from the ability to relate different information in a spatial context and to reach a conclusion about the relationship.

Grekousis, G., & Photis, Y. N. (2014). Analyzing high-risk emergency areas with GIS and neural networks: The case of Athens, Greece. The Professional Geographer66(1), 124-137.

I have acted with honesty and integrity in producing this work and am unaware of anyone who has not. -Daniel Buffington

Unmanaged Cat Colony Distribution in Auckland, New Zealand Over 20 Years

In New Zealand, feral cat populations have steadily increased with urbanization. The increasing cat populations have led to the development of feral cat colonies. While many of these colonies have people that exert some degree of ownership and thus act as caretakers, many others are no one managing them. This situation is damaging to both the cats and wildlife. These colonies often negatively impact wildlife populations through over-hunting, and due to no human intervention providing necessary veterinary care, these cats are often much less healthy than both cats in managed colonies and non-colony feral cats.

To examine what determines distribution of unmanaged colonies in Auckland, New Zealand, Glenn Aguilar and Mark Farnworth collected data from the Lonely Miaow Association Incorporated for the years 1991 through 2011. They determined the density of cat colonies in Auckland and compared this data to the human population density, land use, and the New Zealand Deprivation Index (NDZI).

The NDZI is calculated using, in decreasing weight, home ownership, employment status, age, qualifications (New Zealand term for the level of education), living space, access to communication, and access to a car.

Aguilar and Farnworth found that cat colony densities strongly correlate with both human population density and Settlement land use, and weakly correlated with NDZI. While they did not find causation, these correlations are important because they can help guide policy and management of these colonies, current and future.

Aguilar, G. D., & Farnworth, M. J. (2013). Distribution characteristics of unmanaged cat colonies over a 20 year period in Auckland, New Zealand.Applied Geography37, 160-167.

I have acted with honesty and integrity in producing this work and am unaware of anyone who has not.

Designing a Structured and Interactive Learning Environment Based on GIS for Secondary Geography Education

GIS can be useful in a number of different ways, collecting, storing, exploring and using geographic data; developing, and presenting geographic concepts;  making, using, and interpreting maps; investigating geographic issues and solving problems.This article reviews the current status of GIS use in schools, the benefits of using GIS information for exploration in everyday learning and the construction of knowledge GIS creates. In the past, not many GIS software packages were specifically designed for school education, however with greater mapping development and GIS tools, more and more schools are able to use this software as an educational tool for teaching and learning activities (typically World Explorer as shown in the map below).

The use of GIS in a classroom setting can change the way students gather and analyze geographic information. School education has also been progressing into more of a hands on and inquiry based learning rather than all lecture. This puts an emphasis on constructivism, which emphasizes problem solving and inquiry-based learning rather than instructional sequences for learning of certain content skills. GIS is used for geographic data analysis, exploration, and visualization which has made it perfect for constructive learning. By organizing data found by using GIS processes, students are able to connect to themes in the syllabus content, and apply geographic skills. So as GIS software and supporting hardware become more readily available at affordable prices, all levels of GIS applications for education continue to expand. creating a more constructive learning environment.  

Suxia, L., & Xuan, Z. (2008). Designing a Structured and Interactive Learning Environment Based on GIS for Secondary Geography Education. Journal Of Geography107(1), 12-19. doi:10.1080/00221340801944425

I have acted with honesty and integrity in producing this work and am unaware of anyone who has not.

Socioeconomic Status and Prevalence of Obesity and Diabetes in a Mexican American Community

Despite the increase of health qualities in the United States over the past 10 years, socioeconomic status still is a major cofounding variable in obesity and diabetes relevance. The consequences of obesity and diabetes are overbearing for taxpayers across the country. As this study was done, the underlying question becomes evident, why are lower economic status families along the Mexican American border plagued with weight related issues? According to the journal, Mexican Americans within the first four household income quartiles had no difference in obesity frequency. But, the first quartiles had much higher chances of having diabetes compared to the third quartile.

As shown in the image above, most of the families living within the first quartile (most poor), lived along or closest to the border between the United States and Mexico. Whereas the third (more rich) quartile, lives farther in Texas.

Fisher-Hoch, Susan P., et al. "Socioeconomic status and prevalence of obesity and diabetes in a Mexican American community, Cameron County, Texas, 2004–2007." Prev Chronic Dis 7.3 (2010): A53.

Strengthening the GIS Profession

The field of Geographical Information Systems is ever-growing at technology continues to develop. For GIS professionals, the solidification of a firm definition for what qualifies as a GIS profession has proven beneficial. The benefits provided by an outlined definition of the field include easier access to appropriate technology and certifications that carry weight. Recently, the US Department of Labor Employment and Training Administration (DOLETA) created a system to categorize different subsections within GIS to provide a rough estimate for how many professionals might be found in the GIS workforce. Although the estimated number accounts for potential overlap, the projected number is impressive: around 425,000 individuals were estimated to work in the GIS profession in 2010, and 150,000 more are expected by 2020.

 A specialized test was developed to check competency in the field that will allow future generations of GIS workers to have a certification with more meaning. In addition, more and more colleges and universities are developing degree plans around Geographical Information Systems, with a particular interest in the professional ethics and morals of the discipline.The field is young, but has extensive potential for growth and contribution.

DiBiase, D., Goranson, C., Harvey, F., & Wright, D. (2009, November). Strengthening the GIS Profession.

I have acted with honesty and integrity in producing this work and am unaware of anyone who has not. Mattie Cryer