My first peer-reviewed, first author paper has been published! “Niche Modeling of Dengue Fever Using Remotely Sensed Environmental Factors and Boosted Regression Trees” has been published in the journal Remote Sensing by MDPI. The links to the abstract and paper are:

PDF Version:


GIS and Science

ghGeospatial Health, Volume 8, Number 2, May 2014, Pages 429-435

By Jia-Cheng Zhang, Wen-Dong Liu, Qi Liang, Jian-Li Hu, Jessie Norris, Ying Wu, Chang-Jun Bao, Fen-Yang Tang, Peng Huang, Yang Zhao, Rong-Bin Yu, Ming-Hao Zhou, Hong-Bing Shen, Feng Chen, and Zhi-Hang Peng

“Influenza poses a constant, heavy burden on society. Recent research has focused on ecological factors associated with influenza incidence and has also studied influenza with respect to its geographic spread at different scales. This research explores the temporal and spatial parameters of influenza and identifies factors influencing its transmission.

Spatial clusters of annual incidence of influenza (hotspots) in Jiangsu province, P.R. China, for the years 2004 (a), 2 006 (b), 2009 (c) and 2011 (d). Spatial clusters of annual incidence of influenza (hotspots) in Jiangsu province, P.R. China, for the years 2004 (a), 2006 (b), 2009 (c) and 2011 (d).

“A spatial autocorrelation analysis, a spatial-temporal cluster analysis and a spatial regression analysis of influenza rates, carried out in Jiangsu province from 2004 to 2011, found that influenza rates to be spatially dependent…

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To test the feasibility of a low cost, mobile environmental sensor system that could be used to sample air quality as needed and in areas where conventional sensor systems may not be available or cost effective.

Based around the low-cost Arduino microcontroller, a GPS shield for capturing geographic location was paired with a relative humidity and temperature sensor to act as a mobile data logger. The relative humidity and temperature sensors were chosen for their cost and ease of implementation as an initial set of sensors. The sensors were mounted at the end of a five foot long section of one-inch PVC mast inside a one-inch to two inch tee fitting. The tee fitting was used to protect the sensors from direct sunlight and weather (Figure 1).


Figure 1

The entire unit is powered by a single 9-volt alkaline battery and housed inside a rigid plastic storage container to protect the equipment from handling and the elements. The 9-volt battery should power the unit for several hours and a 9-volt lithium may provide even more operating time (Figure 2).


Figure 2

Software was modified based on that supplied by Adafruit industries, the makers and suppliers of the sensors and GPS unit. The software reads the raw GPS datastream and parses out the $GPRMC string, reads the relative humidity and temperature sensor, then writes these values as a line to a comma separated value text file on a microSD card on the GPS shield. Each additional reading from the time the unit is started is appended to this text file. If power is interrupted to the unit, when it restarts it will create a new file before appending data.

For the initial test of the unit, it was placed inside a backpack with the mast rising to approximately seven feet above the ground. The trip was made on a standard mountain bike and ridden at a nominal pace. The initial test site chosen was a road that runs from north to south from West Walnut Street in Greencastle, IN to the DePauw Nature Park parking lot. There is a change in elevation of roughly fifteen feet where the road enters the forest area at the north end. Otherwise the road is nearly level throughout. The distance covered was approximately 1.7 miles roundtrip and the sensor unit gathered 1059 data points during this trip. Riding was done by staying as close as comfortable to the outside edges of the road for not only safety reasons, but to also help determine the accuracy of the GPS unit.

The unit was turned on and allowed to get a fix on the satellite constellation, then an additional five minutes was allowed to elapse to allow the sensors to acclimate to ambient conditions. Upon return to starting position, the unit was turned off and the file from the microSD card removed and the file copied off.

The data file was opened in Microsoft Excel and the GPRMC latitude and longitude coordinates converted to decimal degrees for use in the GIS. This was done by extracting the degree portion of the latitude string, dividing the rest of the string by 60, then adding the two back together. The temperature was also converted from degrees Celsius to degrees Fahrenheit using the standard formula. Table 1 shows a sample of the raw data file collected and Table 2 shows a sample of the finished spreadsheet.


The resulting Microsoft Excel table was then opened in ArcGIS 10.1 and the XY data used to plot the points (Figure 3).


Figure 3

The projection used by the GPS constellation is WAS 1984 and that was what was used here. A basemap of aerial imagery was then added for reference. Finally, the point data was buffered to 25 meters, the points were kriged, and then the kriged raster was clipped using the buffer (Figure 4).


Figure 4

This project has shown the feasibility of using low cost, mobile arduino-based devices as environmental sensor systems that could be used to sample air quality as needed and in areas where conventional sensor systems may not be available or cost effective.

Several future considerations should be considered, including increasing the number and type of sensors such as adding benzene, NO2, or similar sensors. Additional or different sensors can be added or changed out with minimal effort in programming or hardware.

Another area of interest would be to outfit similar units with small solar panels and battery backup systems so that they could be placed in remote locations, thereby increasing the ability to monitor environmental pollution throughout a much wider area.

Now more than ever, we as users of Geographic Information Systems (GIS) – both professionals and non-professionals – need to be more vigilant in our use of these technologies. Big data, satellite imagery, social media, and GIS all come together to allow an unprecedented level of information sharing that has never before been available. What sparked this blog post is in response to several tweets and retweets today regarding a map that was published online and freely viewable in response to a recent tragedy. I will not share the link or point fingers, as this occurrence is just the latest in a trend I see becoming ever more prominent.

In this particular situation, the map shared with the public shows individual victim locations of the recent tragedy down to the parcel coded level (in other words, a clickable point was placed on the roof of the victims home). Along with this highly accurate location, personal information, including whether the victim is alive or dead or missing, their address and a photograph of them pop-up when clicking on any of the points. While the people who created the map I am sure had nothing but good intentions, and felt they were respecting the victims while doing a public service, the problem is that they were clearly not trained in the ethical use of GIS technologies. I see this as becoming an ever increasing problem as more and more information is made available about our lives, and the ease of creating maps that can be shared in near-real time over the Internet by anyone with a computer continue to evolve and mature. “Just because we can map something, does not mean we should map something.” This also goes beyond improper use of GIS, but also to poor GIS. A person with no training in spatial statistics, cartography, visualization, and a host of other skills, can now sit down, put together a map in a matter of minutes and share it with the world. While this is wonderful from an open-source point of view, it can also lead to erroneous or misleading conclusions and, in this case, violations in privacy.

So rather than just rant about this, here are some things to consider and think about the next time we sit down to create a map for public dissemination.

From the GIS Certification Institute’s “Code of Ethics” under Part IV Obligations to Individuals in Society

1. Respect Privacy

  • Protect individual privacy, especially about sensitive information.
  • Be especially careful with new information discovered about an individual through GIS-based manipulations (such as geocoding) or the combination of two or more databases.

2. Respect Individuals

  • Encourage individual autonomy.
  • Avoid undue intrusions into the lives of individuals.

From “The Ethics of GIS” by Jeremy Crampton, published in ‘Cartography and Geographic Information Systems’ Vol. 22, No. 1, 1995, page 87 “In relation to infringements of privacy by spatial data collection, a commonly made counterargument is that despite the wide availability of personal information in databases, people’s privacy cannot be infringed if analysis is at the aggregate (census block or neighborhood) level. It is argued that this ensures no personal information is ever made available, and that individuals are unaffected by aggregated data.”

Finally, From “Crisis Mapping Needs an Ethical Compass” by Nathaniel Raymond, Caitlin Howarth & Jonathan Hutson downloaded from, “These new uses of crowd-sourced data, the rise of social networking, and the integration of geographic information systems with satellite imagery have not only transformed rapid responses to political unrest and natural disasters, but have in fact begun to fundamentally alter the very nature and arc of the emergence themselves.” And also in that same publication, “It must be determined whether experimental projects that use satellite surveillance, crowd sourcing and interactive map-making in new ways during a crisis constitute human subjects research, and thus require institutional review board approval and oversight.”

While I am not suggesting with that last comment that every mapping project like the one being discussed needs IRB approval, it highlights the importance of how careful we all must be before we release a map, especially during a natural disaster or other event, and consider those that are being mapped and how it will affect them and their families.

Back on January 6 of this year Kevin Butler posted a great article on converting Landsat 8 thermal bands to at-satellite brightness temperatures using the Raster Function Template Editor. The link to his article can be found here .
I will admit I have never used the raster function editor (ok, I didn’t even know it existed), so not being familiar with the raster editor, I had a hard time trying to follow Kevin’s instructions. I am familiar with ArcGIS’s Modelbuilder, though. Using the valuable information in Kevin’s article as a guide, I created a model that does the same thing. The result turned out pretty well and I have included it here as a toolbox that can be added to ArcGIS. You are free to use, modify, and/or change it all you want. All I ask is that if you find it useful or have any comments about it, let me know.
To use the tool, click on the link above and save the Landsat8.tbx file to your computer. Next, open ArcGIS and make sure the Toolbox side-panel is visible (The ESRI website has better instructions for adding toolboxes here . Right-click inside the panel and select “Add toolbox…” from the menu. Navigate to where you saved the Landsat8.tbx and select it (do not open it to show the model, just select the .tbx file). The Landsat8 toolbox is now added. Open it and inside there should be a model called LS8Therm.
Double click the LS8Therm model and enter the location of your Landsat 8 Band11 image, Band12 image, and where to save the output and what to call it (I used .tif files when I created the model).


Click ok and the tool should run;


I ran the tool using the LC80210322013121LGN01 dataset I downloaded from the USGS. Here is the result;


And zooming in for a closer look at Indianapolis, IN;


And then adding a quick symbology;


For anyone that wants to play around with the model, you can right click the model in the toolbox window and select edit. This will open the model in Modelbuilder.

One thing I did not do was preprocess the Landsat 8 data for cloud cover. On the left side of the above image you can see what looks like a series of lakes just to the west of the city. This is a line of clouds, so ideally you would preprocess to reduce cloud cover. The purpose of this was to show urban heat island effect, as can be seen by the darker red of the city compared to the outlying areas. If you were to add a shapefile of the administrative districts, they would follow the outlines of the high-heat areas very closely.


Allen, D. (2011). Getting to know ArcGIS Modelbuilder. Redlands, CA: Esri Press.

Butler, K. (Jan. 6, 2014). Deriving temperature from Landsat 8 thermal bands (TIRS). Retrieved from

Trapped in the house with the wife and two dogs during this recent winter storm, I watched the twelve inches of snow blow across the yard into three foot high drifts. I even took a few pictures and posted them to Picasa, you can peruse them at your leisure here (
What does this have to do with geography and GIS you ask? Glad you did, or were going to, or have been led to believe. The same processes that created the snow dunes and keep me from escaping, I mean, taking my wife out, I mean to the store, are the same processes that create the dunes we see in deserts and arid climates. In fact, the area around central Indiana was also created by the same eolian (wind driven) process as created the drifts in my yard. As the glaciers retreated from this area over 12,000 years ago, they left behind all the sediment they had scraped up along the way. The very lightest particles, the silts and clays, were then blown by the wind across the region, creating dunes which were covered with vegetation so that and all that is left behind are the gentle undulations and rolling countryside. So that is why snow dunes are worthy of a geography post. Now if you will excuse me, I hear the snow shovel calling my name again.

Well, the semester is over and it looks like I did very well (current cumulative GPA nudged up to 3.866). Now to kick back for a couple of weeks, enjoy the holidays, and catch up on all the things I got behind on lately.
To kick things off, here is a short video on projections. I saw a clip floating around the Internet from a TV show called the “West Wing” where a group was trying to get the most popular map projection used replaced with theirs, and thought “Hey, maybe I should explain this a little.”
As always, your feedback is welcome.