GIS 1 : Lab 3

Bears, Python, and Habitats

By: Joseph Mandelko

The focus of Lab 3 is to successfully use various geoprocessing tools to analyze vector data in ArcGIS to find appropriate habitats for black bears in central Marquette County in Michigan. The scenario is that I am working for the Michigan DNR to find where the black bear population they have in Marquette County is currently and what types of land the bears tend to prefer as a habitat. I was then tasked to find the areas of that habitat that were included in the land the DNR is already managing. Lastly they wanted the areas of bear habitat on their land to be at least 5 kilometers away from any urban areas.

To complete the objectives laid out for me I used the tools in Arctoolbox to intersect, clip, erase, join, buffer, and dissolve what I needed to in order to get the information on the map display as simple as possible while still displaying the required information. Perhaps one of the most important and useful tools learned in this lab was the intersect tool. It was needed to put two data sets together on the map display temporarily so I could work with one simple data set not two data sets. For example, after finding the land that belonged to the DNR, where bears tend to live, and in the areas near streams, I could intersect them all together to create one simple dataset. After I had that feature I could subtract the data feature I had created displaying urban areas. From that point I simply had to erase the intersected data set from the areas covered by the urban areas buffer. What remained was my final answer of where bears could live on DNR land.

I also used Python to test a few of the tools using a different input method. My paired down written code is an example of tool use from python. This code creates a buffer of 1 kilometer around streams in the study area. Then the urban areas are subtracted to get areas near streams that are not urban areas (figure 1). The entire collection of tools and data sets I used can be seen and followed in my data flow model (figure 2).

What I found is that there is ample area for an established black bear habitat in central Marquette County in Michigan. The bear habitat is seen in the green crosshatching feature on the map. This is the area that can be on DNR management land, near streams, and suitable for bears as well as being at least 5 kilometers from urban areas. The red striped area is the suitable bear habitat fitting all of the requirements except that of being far enough away from urban areas and populations (figure 3).