In Lab 4 our goal was to take data originally accessed from the Michigan Department of Natural resources combine with our ArcGIS suite of programs to generate a cartographic representation of bear habitat in part of Marquette County, Michigan. Along with a map we were tasked with creating a digital data flow model representing the tools and paths used to analyze the given data and adapt features in order to create our map. In the process of this we gained further experience with vector analysis tools including clip, erase, intersect, and dissolve.
Objective I
The first step for this lab was getting to know our data. This involved checking the file types we were given and what coordinate system the would be represented in in the ArcMap program.
We were provided with a file of X,Y coordinates for bear locations within a study area in Marquette county, Michigan. We were also provided with other relevant features of the study area including the study area itself, land cover types, streams, and DNR management areas. The features were originally added to the program as a feature dataset that was not permanent and had limitations as to the tools that could be used. To get around this we simply exported the feature and data, making them a permanent feature class.
Objective II
Next we started adding some of the major features including the bear locations, streams and the study areas. By performing a spatial join of the bear coordinate data and the land cover data, we were able to determine what type of cover each of the bears was found in. By summarizing the joined data tables we determined what three habitats the bears were found in most often; mixed forest land, evergreen forest land, and forested wetlands.
Knowing that streams are usually an important resource for bears, we calculated the percentage of these bears that were spotted near a stream. To do this we simply selected, by location, bears within 500 meters of a stream and found that 49 of the 68 bears we sighted within this distance of streams. This constituted 72% of the sightings which would lead us to believe it is an important habitat characteristic to bears.
Objective III
The data gained in objective two was next used to find possible habitat for bears based on cover types in this study area. To do this we selected the three types where the most bears were found and created a new layer from those selected features. This gave us a new representation of them, but there were still lines that visually separated the types from one another within the single feature. We used the dissolve tool in ArcMap which allowed us to remove all of the lines separating cover types.
Next, we needed to define the area within 500 meters of all streams as a possible habitat for bears. The original streams feature was expanded using the buffer tool. This tool can create a feature that includes an area of a specified distance around a feature, so we simply chose the streams feature to buffer and specified an area of 500 meters arouund it as the "buffer zone".
Now we needed to define the area that the bears used for habitat by selecting features that shared both the proximity of 500 meters and the appropriate area of cover. To do this we intersected to two layers created so far in objective three. The intersect tool takes areas of the two features that overlap and turns those sections into another new feature. We now had a feature that displayed areas of bear habitat that had both the right type of cover and the correct proximity to streams while eliminating areas that didn't have both of those properties.
Objective IV
For objective four we wanted to find areas of bear habitat that were located within DNR management lands. We simply needed to use the intersect tool again. This would create a new feature showing areas where both the DNR management areas and the proposed bear habitat overlapped.
To make things a bit more difficult, the feature showing DNR management areas that we were given was segmented into separate units. We used the dissolve tool again to remove all boundary lines inside of the new feature of DNR managed bear habitat.
Obective V
The DNR would likely not want to maintain habitat for bears too close to urban areas as it could bring them in close proximity to people. Therefore we were next assigned to remove any bear management areas within five kilometers of urban or built up areas.
To remove management areas within this distance we first defined what areas were urban or built up by selecting them from the land cover feature. We then created a new feature out of that selection just as we did in objective three with the habitat cover types. Next we added a five kilometer buffer like we did for areas near streams in objective three.
We now had a feature of an area that could be removed from our map of DNR managed bear habitat. In order to do this we used the erase tool. This tool allows us to select one feature, and then remove areas of another feature that overlap it. We did just this and removed the five kilometer area around urban buildup and erased its features that overlapped the map created in objective four.
Objective VI
Finally we were tasked with creating a cartoghraphically pleasing map that showed our proposed bear habitat and areas of it that could be managed by the DNR. This also involved adding a visual reference of the study area within Marquette county and within the state of Michigan. Other necessary elements such as a title, legend, scale bar, and north arrow were then added along with features defining the bear locations and streams in the study area.
(Fig. 1)
We were also asked to create a data flow model of all of the tools and processes we used to create our map. This can be done using a number of programs that visually aid such a process, but I chose to use the ModelBuilder element of the ArcMap program. This program allows users to select tools from the ArcToolbox directly and drop them into the model being built. It automatically creates representations of the tools that can edited to show input and output representations.
Each process can be visually linked in this way to create a model of how the map was developed. The model can also be used in the program to process initial data in the exact manner we did. So if someone were to have data from another county they would simply need to define each variable and this model could run through the process for them. (Fig. 2)
Results
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| Figure 1. Final map including Proposed bear habitat along with areas managed by the Michigan DNR that are within that habitat. Due to their relevance streams and bear locations were also added. |
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| Figure 2. Data flow model used to show what tools (yellow squares) and the input features for those tools (circles). The blue circles represent original sourced features while the green circles represent adapted features created by the tools shown. |
Michigan Center for Geographic Information; Michigan 1992 NLCD Shapefile by County; 01 November, 2002; <http://www.mcgi.state.mi.us/mgdl/nlcd/metadata/nlcdshp.html>; (04 December, 2014)
Michigan Department of Natural Resources; wildlife_mgmt_units; August, 2001; <http://www.dnr.state.mi.us/spatialdatalibrary/metadata/wildlife_mgmt_units.html>; (04 December, 2014)
Center for Shared Solutions and Technology Partnerships; Michigan Geographic Framework: Marquette County; 01 June, 2014; <http://www.mcgi.state.mi.us/mgdl/framework/metadata/Marquette.html> (04 December, 2014)
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