Maps (2 of 3)

Tsetse Fly Hotspot Mapping

When I was finished with the Kereda Reservoir Map, I decided to set my sights on the Tsetse fly mapping. The data that I would need was with the ICIPE, so I needed to visit them before I could complete the maps (actually, I needed to get some of the data for the Reservoir project too). I set a meeting with the ICIPE (African Insect Science for Food and Health, http://www.icipe.org) , and within a few days I was off to their office on the east side of Addis.

At the ICIPE office, we had a short meeting where I told Dr. Shiffa and Gibsan (a GIS beginner at their office) about the map that I wanted to make for them. The map, which would predict where Tsetse flies would breed, had two problems. Changed to “One problem was that the data I needed might not actually exist yet (it was precipitation data that still needed to be collected). The second roadblock was that the GIS coordinator of ILRI, who was in control of all of the information for the project was away for a month, due to Ramadan. So I was in a bit of a bind. I asked Gibsan if she had any data I could use in the meantime.  She was able to give me part of the data that had already been collected from the traps, although this data had been severely diminished after viruses caused a set of computer crashes.

Anyways, the data that I wanted didn’t exist, the data that did exist wasn’t available, and the little data that I could have had been ruined by a computer virus. This trip across town was turning out to be a bit of a letdown. I think Dr. Shiffa and Gibsan realized this and so they invited me to get a coffee with them on the other side of the campus. On the way we dropped by the office where the ILRI coordinator usually worked (although he was now away) and Gibsan decided to see if anyone was there, just in case. In a stoke of good fortune, we did find someone who said that she could find the data that we needed the following morning (it was near the end of the day) if need be. We set up a time for the following day and all was set! Problem (well, one at least) solved!

With this good news and a well crafted coffee in me, I picked up the little data that ICIPE had recovered and went on my way. The following morning I went back to the ILRI campus, met with the ILRI GIS staff member and she was able to give me the data that I needed. I then went back to AgriService, added the data to the Kereda Reservoir map and began to look at the Tsetse fly data.

The Tsetse fly data that I had received had three months and a half of complete data. I decided to make a hotspot map of the collected fly populations for the three complete months and to make a side by side comparison of the data. This way a map could illustrate how the Tsetse fly population was correlated (or not) with seasonal changes. The incident rate of Tyrpansomiasis (Tsetse fly sickness) in cattle was often greatest in the summer months, and then declined towards the winter months, and I was hoping to show that with the time series in the maps.

Making the maps was pretty straightforward. I formatted the data in excel and imported the trap location and information into ArcMap easily. Then I created an IDW (Inverse Data Weighted) surface across the trap locations which showed the prevalence of common type of Tsetse fly, the G. Moranis. I made these maps for each of the three months; July, August and November. I also made graphs of the number of flies within each of the data categories I had used in the maps, and put those in the map layout. The final map (below) pretty clearly shows the way that the populations change through the three months, so mission accomplished.

Temporal and spatial distribution of the Tsetse Fly in the Gelana Valley

Next up: Small Scale Irrigation Schemes!