Monday, February 22, 2016

The effects of deforestation and climate variability on the streamflow of the Araguaia River, Brazil

Agricultural demand and deforestation has transformed land use in Tropical South America in the last four decades. Changes in land use affect the hydrology of the region and can lead to a variety of hydrological and geomorphological changes. Previous studies (Costa et al. 2003 and Coe et al. 2009) have used models to correlate the increase in water discharge rate to deforestation of the area and climate variability. Coe et al. (2011) uses these methods to analyze discharge data and climate data in an 82,600 km2 basin of the Araguaia River in South America which is the center of agricultural and cattle production for the region. Discharge and precipitation data between two time periods (1970-1979 and 1990-1999) were used to compare low and high density land cover respectively. Two different simulations with different land cover (but identical climate forcing) were used. The first was IBIS-POT wand the second was IBIS-GRASS which represented undisturbed and disturbed land cover respectively.  

Mean discharge for the basin increased by 25% between the two decades and the mean ratio of runoff to precipitation in each decade increased significantly by 4.8%. Although precipitation rate increased by 2.5% between the two investigated decades, this change was not enough to explain the increased discharge rate. This means that discharge increased between the two decades analyzed, but was  not attributed to increased precipitation. Coe eta al. believe this change is a result of changed land cover because the climate data that was used to model the two-time period were exactly the same. This can be explained by the fact that changing the plants of the area often leads to increased discharge and soil erosion because water is not infiltrating the ground because agricultural crops often do not have the same root depth or density.

Coe, M. T., Latrubesse, E. M., Ferreira, M. E., & Amsler, M. L. (2011). The effects of deforestation and climate variability on the streamflow of the Araguaia River, Brazil. Biogeochemistry105(1-3), 119-131.

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

Remotely sensed evidence of tropical peatland conversion to oil palm

Deforestation is being driven by global demand for food and biofuels. Oil palm is an edible vegetable oil from the oil palm tree that is primarily produced in Indonesia and Malaysia, accounting for 87% of global production. Although it has been proposed that the cultivation of oil palm has led to a decline in biodiversity, few studies have attempted to quantify the environmental impact. Koh et al. use GIS to analyze land use in Southeast Asia, quantify the amount of peatland transformed by oil palm production and quantify the effect of cultivation on biodiversity.

A land cover map (250-m spacial resolution) and digital elevation data was used to map the oil palm cultivation in Southeast Asia. Land cover was classified into clusters using an algorithm which were then assigned to one of five types of land cover (water, forest, plantation/ regrowth, mosaic or open) and 12 land cover classes. Accuracy of identification was assessed using satellite images at 1-m resolution. According to Koh et al., 98% of the area analyzed was correctly categorized to be oil palm and 85% of closed canopy oil palm could be identified. A majority of the land that was used for oil palm production was not peatland (90%) and only “6% of total peatlands within our study region had been planted with oil palm” (5129). Sub-regions had the highest percentages of peat-swamp loss to oil palm with the most affected regions being North Sumatra, Bengkulu and Peninsular Malaysia. These data show that the analysis used was able to correctly identify large (>200 ha) oil palm plantations and that plantations have had a larger impact on the sub-region level than on the regional level.

Koh, L. P., Miettinen, J., Liew, S. C., & Ghazoul, J. (2011). Remotely sensed evidence of tropical peatland conversion to oil palm. Proceedings of the National Academy of Sciences108(12), 5127-5132.

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


Karen Willett and Eric Sanderson

Over the past 10 years, the use of GIS as an analytical and visualization tool for conservation purposes has experienced dramatic growth. As a conservation application, GIS has been used for population estimates of forest elephants, planning nature reserves, evaluating management scenarios in space and time, and range-wide priority setting for tigers and jaguars. Increases in the use of GIS applications have been caused by improvements in software and hardware that make GIS easier to use and cost less. Easier use and affordable cost allows some small nonprofit organizations and even individual scientists and researchers to have access to a tool that was primarily only accessible to large agencies and experts(primarily the government). Due to the improvements seen today, analysis with GIS is accessible to most ecologists, land managers, and conservationists (even those who work out of the country). Because GIS has become more useful to researchers and conservationists it is being brought out to those who work out in the field, in particular the Wildlife Conservation Society (WCS)(Founded in 1895 as the NY Zoological Society headquartered at NYC Bronx Zoo, works to save wildlife and wild lands around the world). The Geographic Information and Analysis Program of the WCS consists of a landscape ecologist, a GIS Analyst, GIS interns, postdoctoral associates, and 300 supporting field biologists practicing conservation in over 50 countries. The program is dedicated to supporting landscape ecology, and geographic analysis including GIS, remote sensing and GPS. The goal of most scientific conservation efforts is to apply information to influence anthropogenic impact natural resources. Data collected by conservation biologists is usually spatially explicit, meaning where the population is observed, where the park boundary is located, and which village is closest. This data is often collected in remote and rural areas but it needs to be communicated quickly in order to help wildlife and wild lands. While training conservation scientists about GIS, it’s been noted that although GIS instructional books and textbooks are easy to understand they can sometimes give unrealistic impressions of how GIS is actually utilized. Tutorials make the use of GIS seem a lot easier than it is in reality when conduction real spacial analyses. In order to effectively use GIS, field scientists need to possess a core set of ideas, vocabulary, and skills attained from literature on spatial analysis techniques. This set of ideas can also be acquired from geography, geodetics, computer science and landscape ecology. The WCS helps scientists acquire GIS skills be providing workshops twice a year in New York, and in different countries that they may be conducting research on. Their curriculum is focused on vocabulary and operations such as raster vs. vector, spatial primitives, spatial data layers and associated data tables, map projections, scale, and other compete at the center of GIS applications. Other topics such as the importance of metadata and the use of remote sensing is also taught. Other than language barriers, some challenges that WCS have encountered while teaching field researchers is that they come to their lessons with preconceived ideas about GIS that are untrue. One such misconception is that “doing research in a carpeted and air-conditioned room will be less frustrating than their field work”(Willett, "Ecology 101: Bulletin of the Ecological Society of America", 2000), others think that GIS is “primarily a tool to print big, pretty maps”(Willett, "Ecology 101: Bulletin of the Ecological Society of America", 2000). GIS is a tool for comprehending and analyzing spatial information, not just an art tool. 

Images from article

Willett, K., & Sanderson, E. (2000). TAKING GIS INTO THE WILD: TEACHING GIS TO PRACTICING INTERNATIONAL CONSERVATION BIOLOGISTS. Ecology 101: Bulletin of the Ecological Society of America.

Five Essential Properties of Disease Maps

Five Essential Properties of Disease Maps
Kirsten M. M. Beyer,∗ Chetan Tiwari,† and Gerard Rushton‡

The past 10 years have seen increased production of disease and mortality maps throughout
the world. Although the spread of these maps exist alongside research on the fundamentals of map design and production, some essential properties of these maps have received relatively little attention, paid specifically from geographers.
These properties include the selection of color schemes, display units, variability of disease rates, brushing techniques, micromaps, and continuous representation. To combat these issues commonly found in disease maps Beyer et. al implemented a method known as adaptive spatial filtering, an adaptive filter of uniform shape that grows inversely with population density for disease rate calculation. In adaptive spatial filtering, a grid is placed over the area. Each grid point is calculated by using a circular filter that expands to obtain observations used in order to calculate stable rates. The user then defines a threshold value to guide the filter bandwidth size (example: expected number of disease events or population size that will result in a stable rate value). The area between grid points is inserted to create a surface representation of a diseased area. The geographic scale of the measured rates of disease vary across the map due to population density and risk of sites. Even though methods such as the census exist, they may not accurately provide data for the use of disease maps. Spatial support for calculation is an important feature of creating accurate disease maps. The differences between age groups, sex and geographical displacement all factor into a population’s susceptibility of disease. Closely related to the control of spatial support is the visual representation of disease. True presentation of disease rates will effectively portray what disease risk patterns look like. Disease maps use bounded measurements, however spatial patterns of risk might actually not follow bounded units. Beyer et. al believe that “risk surfaces are more continuous in nature, varying along with biological, social and environmental characteristics of populations”(Kirsten M. M. Beyer, Chetan Tiwari & Gerard Rushton (2012): Five Essential Properties of Disease Maps). Maps that use bounded units actually prevent the observation of varied risk that might occur in populations. To combat this, Beyer et. al suggest that using an intensity function will represent a continuous surface. On major criticism of disease maps is that defined boundaries remove some spatial details from the map. However, using spatial support methods are in units that are too small to contain enough observations for an accurate calculation in rural areas. By increasing or decreasing the number of filters based on population density, the heterogenous nature of population distribution allows that distribution to guide the spatial detail. Traditionally in the United States, disease mapping is constructed by direct age adjustment, which multiples local disease rates by standard population rates. This is effective when the local area being measured has the same age-sex composition as the standard population. However, when the purpose of the map is to compare different disease rates on local populations, direct adjustment is ineffective. Indirect methods should be applied because it has the advantage of rate stability and maximizes geographic detail reliably for small area populations. Because disease maps should be available to public health practitioners as well as the general public, it’s important that they can be read easily. The scale and color scheme of each map should effetely portray the information in a way that a person without a medical practitioner back ground can understand. Heart Disease Death Rates for 2011 through 2013 for Adults Aged 35 Years and Older by County. The map shows that concentrations of counties with the highest heart disease death rates - meaning the top quintile - are located primarily in Mississippi, Oklahoma, Louisiana, Arkansas, and Alabama. Pockets of high-rate counties also were found in Georgia, Kentucky, Tennessee, Missouri, and Nevada.
Image from:

Kirsten M. M. Beyer, Chetan Tiwari & Gerard Rushton (2012): Five Essential Properties of Disease Maps, Annals of the Association of American Geographers, 102:5, 1067-1075

GIS and Tornadoes

Tornado characteristics and mapping are fundamentally a GIS based field of work due to heavy reliance on “geographic space” to map out tornado densities (Deng, Wallace, & Maasseen, 2016, p. 284).  Because of this GIS influence, Deng et. al worked to provide a definition of tornadoes in GIS terms. They essentially outlined three facets of such definition arguing that a tornado is:
  • “Dynamic event in space-time”
  • “Truly three-dimensional in geographic space”
  • “Has its own geometric, thematic, and temporal properties”  (p. 284)
In order to identify tornadoes and their density, an area must be specified. The “adjustment of the area in shape and size” alters the “density reading” (p.284) of tornadoes for the locations. The image below depicts tornado densities of the Eastern United States at 12 variations of neighborhood scales “ranging from 20-360 km” (p. 294). The distance decay function used in this analysis affects the amount of “smoothing” of the projection. The bigger the distance is between sites chosen, the more amount of smoothing occurs affecting the interpretation of each map.

The overall argument to the work of Deng et al. is that tornado density models are “relative” and the models depend on the “neighborhood size, the choice of the distance decay function, and the involved tornado properties” (p.294). Understanding the methodology behind certain maps and GIS information allows for higher understanding of the subject, decreases potential false readings, and allows for alterations in maps using the same data to be comprehended.

Deng, Y., Wallace, B., Maassen, D., & Werner, J. (2016). A Few GIS Clarifications on Tornado Density Mapping. Journal Of Applied Meteorology & Climatology, 55(2), 283-296. doi:10.1175/JAMC-D-15-0141.1

I have acted with honesty and integrity in producing this work, and am unaware of anyone who has not - Hailey Johnson

Applied GIS: Web GIS Serving Public Safety in Central Asia

    Central Asia as well as a surrounding web of nations are widely affected by illicit drug trafficking, specifically due to the “poppy seed cultivation in Afghanistan” (Kurbanov, 2015, p. 69). The wide trafficking of this drug continues to cause  issues within Afghanistan and surrounding nations relating to “security, good governance, and socio-economic development” (p. 69) causing instability within these countries as a result. By making spatial analysis and GIS based databases more accessible across the public, the United Nations on Drug and Crime worked to combat this issue.
    The Drugs Monitoring Program (DMP) is one GIS web sharing tool that specializes in “collecting, monitoring, and sharing drug-related data” (p. 70).  This tool is comprised of a layering system including the “user interface layer, application layer, and database layer” (p.79). Interactive maps concerning drug trafficking has resulted from this tool providing not only a  “provincial and district” measure of drug data within Afghanistan, but also current drug data and analysis worldwide as well. According Kurbanov (2015), “As of June 2015, over 180,000 drug seizure cases are registered on the [DMP] platform” (p.70). Below depicts worldwide global seizures of drugs.
Additionally, information such as “drug and precursor substance prices” as well as the significant drug affecting as specific area within an individual country can also be provided using the DMP.

With tools such as Web-based GIS providing up-to-date statistics, trends, and “hot spots” on issues such as illicit drug trafficking, a comprehensive analysis of these issues can be made and the results of such analysis can be widely accessible to both GIS experts and non experts. Global awareness and collaboration provided by such accessibility would allow for more logical, effective policies to be made in order to combat the impacts that crimes such as drug trafficking are having on populations and environments affected.

Kurbanov, O. (2015). Applied GIS: Web GIS Serving Public Safety in Central Asia. International Journal Of Geoinformatics, 11(4), 69-74.

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

Sunday, February 21, 2016

Accuracy of GPS positioning on the iPhone 3g

This study presents an evaluation of the accuracy of locations obtained using Assisted GPS (A-GPS), WiFi positioning, and cellular network positioning modes on the 3G iPhone. Results indicate that A-GPS locations obtained using the 3G iPhone are much less accurate than those from regular autonomous GPS units (average median error of 8 m for ten 20-minute field tests) but appear sufficient for most Location Based Services (LBS). WiFi locations using the 3G iPhone are much less accurate and fail to meet the published accuracy specifications.
Positional errors in WiFi also reveal erratic spatial patterns resulting from the design of the calibration effort underlying the WiFi positioning system. Cellular positioning with the 3G iPhone measures as the least predictable and least accurate positioning method. It can sometimes be off be several miles. The above pictures shows from a GIS perspective the positioning and accuracy of each type of GPS tracking. It clearly shows that GPS positioning is the most accurate, however, even still it can be hard to pinpoint the exact location. However, as time goes on, these GPS systems, including cellular positioning, will continue to become more advanced and more accurate.

Zandbergen, P. A. (2009). Accuracy of iPhone locations: A comparison of assisted GPS, WiFi and cellular positioning. Transactions in GIS13(s1), 5-25.
I have acted with honesty and integrity in producing this work and am unaware of anyone who has not. - Daniel Buffington

Mapping Invasive Trees By Satellite

Saltcedar, also called tamarisk, is an invasive plant originally from Eurasia and Africa. Tamarisks were introduced as windbreaks and to control erosion. They've dominated areas of the arid southwest, outcompeting native cottonwoods and other trees. 

Le Wang, Silvan-Cárdenas, Yang, and Frazier used high spatial resolution technology to map these invasive species by identifying them based on visible canopies. This technique has also been used to map other invasive tree species with a good degree of success. This particular study was focused on an area of the Rio Grande near the town of Candelaria. Each pixel on the map was given a value, for example: green saltcedar, brown saltcedar, mesquite, unknown bush, water, road, et cetera. These were consolidated into three categories: invasive, noninvasive, and clear. 

When analyzing the accuracy of this mapping technique, the study found that the degree of accuracy definitely correlated with atmospheric conditions, and that the differentiation of different life-stages of the target tree (green saltcedar versus brown, dry saltcedar) greatly improved accuracy. 

This sort of technique only works on particular types of species, namely those whose canopies are both visible and easily distinguished from other trees. However, for the species this does work on, this would be a very useful tool for observing and managing invasive species. 

Le Wang, José L. Silván-Cárdenas, Jun Yang & Amy E. Frazier (2012): Invasive Saltcedar (Tamarisk spp.) Distribution Mapping Using Multiresolution Remote Sensing Imagery, The Professional Geographer, DOI:10.1080/00330124.2012.679440

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

Communicating Geographic Information in a Digital Age

Communicating Geographic Information in a Digital Age
Michael F. Goodchild

The term Geographic Information has multiple definitions, but is easily defined as “information about the distribution of phenomena on the surface of the earth (and the near-surface)" (Goodchild,Communicating Geographic Information in a Digital Age). Loosely, the term refers to any information used to describe the Earth’s surface and the human happenings that occur on it that is communicated between people using technological terms and formats shared between the sender and the receiver. When the communication of geographic information was first introduced, it was seen as a metaphor for a processing engine. Analysis was seen as the motivating force behind GIS. The user was seen to be empowered through hardware, software, and date integrated through the user interface. However the metaphor view has been challenged by the introduction and development of the internet. In this new digital environment, “computing technology’s primary function has become the mediation and facilitation of communication between people”(Goodchild). Long term impacts of the digital transition have been obvious do to the social and institutional arrangements it has caused. GIS software has become more affordable and digital communication more accessible. In his article, Goodchild observes how computing is dominated by a “paradigm of human communication”, and that the processing engine does not explain the rapid growth in the adoption and use of computing technology. 

Image from

 Goodchild, M. F. (2000). Communicating Geographic Information in a Digital Age. Annals of the Association of American Geographers, 90(2), 344-355. Retrieved February 21, 2016.

Teaching GeoDesign: A Campus-Wide Initiative by Ming-Chun Lee, Ph.D.

Teaching GeoDesign: A Campus-Wide Initiative by Ming-Chun Lee, Ph.D. 

In recent years, GeoDesign has become a popular topic in the GIS community. Academics, practicing GIS communities, design and planning activists, and geospatial technology industries are all working together to create a definition to what GeoDesign encompasses and develop it into a practical design and planning framework. There are different opinions to what GeoDesign actually is, but in short GeoDesign combines GIS with designing the environment. In one way GeoDesign is an application that comes from geospatial analytics. In another it can allow us to “see through” earth’s landscape in order to understand the planet as a living system. Ultimately every party that collaborated on defining this term decided that it was just what it sounds like, something that combines GIS with design. GeoDesign allows people to design more closely to the environment, providing a “more synergistic coexistence”. Students involved in GeoDesign are taught to gain an awareness of the planet that will allow them to engage with the environment by learning relationships between the physical landscape and human systems. GeoDesign aims to “create and maintain more sustainable environments, communities and landscapes for the benefit of future generations”. 

Lee, M. C., Ph.D. (n.d.). Teaching GeoDesign: A Campus-Wide Initiative. Sustainability on the UT Campus: A Symposium, 1-4. Retrieved January 25, 2016, from file:///Users/perikincaid/Downloads/Lee-2012-Geodesign.pdf.

Mapping Commemorations of Black Historical Figures

How are Black historical figures commemorated within a white power structure? A study by Eliot Tretter used GIS to map places in the United States named after Black historical figures. What he found shows patterns of how our society fits black historical figures into our historical memory.

Tretter focused on "mundane" features, such as streets and parks, rather than museums and monuments. He found that Martin Luther King makes up the majority of commemorations - roughly two thirds. Commemorations other than MLK are few and far between. Very few of these commemorations were of women. Tretter explains that this reflects our perception of the Civil Rights movement as a movement led by a single powerful man, ignoring many of the local and powerful women leaders. This effective erasure of female leaders in the movement, explains Tretter, risks "stifling how we understand women's roles in present-day political and social life" (44). 
By quantity (1st map), the commemorations show up most in the South, in New York, and in California. When distributed by capita (2nd map), the South has by far the most commemorations. Over 20% (44% excluding King) are in large cities. Almost all figures were commemorated in their birth states (not all). Not all were commemorated in states they lived a long time in or died in. One example is Harriet Tubman, who spent much of her life in Pennsylvania and Delaware, but is not commemorated in either state. Hers and other examples show a Northern bias - African Americans were less likely to be commemorated in Northern states than Southern ones, even when they spent a significant portion of their lives there. This is problematic, explains Tretter. Combined with Martin Luther King as the single representative of Blacks in history, this portrays African Americans as only being part of history during the Civil Rights Movement, and absent from all other spheres of history. 

Tretter argues that monuments and commemorations help to create collective memory of the past. When Black historical figures are only represented when it comes to the Civil Rights Movement, white becomes a default to use in any other area of history, which is not a true or just portrayal at all.

Eliot M. Tretter (2011): The Power of Naming: The Toponymic Geographies of Commemorated African-Americans, The Professional Geographer, 63:1, 34-54

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

Socioeconomic status and obesity

    Socioeconomic Status and Prevalence of Obesity and Diabetes in a Mexican American Community      
      Studies have recently shown that the Mexican American population is at a higher risk for obesity and diabetes. A study was done in Cameron County, Texas from 2004 to 2007 to find more data to analyze the results of previous research. This study, which documented a county near the border of Mexico, surveyed a population of 810 Mexican Americans between the ages of 35 and 64. There are many factors that can affect obesity including economic class and the culture of the surrounding area. The areas bordering Mexico have some of the highest rates of obesity in the country.

            The 810 participants in the study were broken in to four socioeconomic groups in order to determine how much economic class affected obesity. The study showed that participants in the lower socioeconomic class had significantly higher chances of having undiagnosed diabetes, while those in higher classes were less likely. Also, higher income had a positive impact on health in this particular community. The graph below shows the percentage of participants with diabetes compared to age and socioeconomic status.

          Studies have also shown across the country that obesity can be affected by economic status. Many factors can support this conclusion, but one in particular is that cheap food is often very unhealthy. From this study we should continue to make healthy food more available and affordable in order to become a healthier society. 

Fisher-Hoch, S. P., Rentfro, A. R., Salinas, J. J., Pérez, A., Brown, H. S., Reininger, B. M., ... & Hanis, C. M. (2010). Socioeconomic status and prevalence of obesity and diabetes in a Mexican American community, Cameron County, Texas, 2004–2007. Prev Chronic Dis7(3), A53.

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

Saturday, February 20, 2016

Lawrence, Kansas Food Deserts

Awareness surrounding the notion of food deserts has steadily increased with time. More and more programs are being created to aid those living in food deserts. Food deserts are expansive areas, specifically in cities lacking full service grocery stores with nutritious food. If people live in a food desert they often have to travel longer distances to purchase food otherwise they’re limited to convenient stores and fast food for the majority of their meals.

“Quantifying the extent and cost of food deserts in Lawrence, Kansas, USA” explores food deserts and illustrates this specific example through the use of GIS. The researchers involved in this study attempt to better understand this given food desert, and map the grocery stores in reference to public transit and population distribution. They do so by sending out 1,000 surveys about their current situation- location, location in reference to the store, and mode of transportation. The research also considers the cost of traveling and the opportunity costs of those who have to travel out of the food desert to purchase their food. Essentially, there are several factors that influence food deserts and restrict access to nutritious food. As previously stated there are outreach programs aiming to rid communities of food deserts through farmers markets and spreading awareness to local governments.

Hallett, L. F., & McDermott, D. (2011). Quantifying the extent and cost of food deserts in Lawrence, Kansas, USA. Applied Geography, 31(4), 1210-1215. doi:10.1016/j.apgeog.2010.09.006