This week we learned the ins and outs of running a Spatial Query as well as creating and working with buffers for multiple map features. We focused on creating a map displaying campsite options in De Soto National Forest near Hattiesburg, Mississippi, based on combined buffer zones within 150 meters of lakes or 500 meters of rivers as well as within 300 meters of a road. We used the union tool to only show areas where the water and road buffers overlapped.
We took the resulting map and made our map layout. This part
was challenging for me, the instructions were to include an inset map showing
the location of the National Forest within Mississippi. Up until now I have
either been given data or instructed on where to download it, but this time it
was up to me to source my own data. I wasn’t even sure where to begin. I
searched Mississippi’s state GIS website as a start but it looks like they’re
in the middle of transferring data to a new system so it took me awhile to find
the correct website, in the mean time I found the US Forest Service’s GIS
website and downloaded the National Forest Land Units data file and added it to
a new map. While gave me a visual of all the national forests in the US, I
wanted my information to be specific to Mississippi, unfortunately there was no
way in particular to specify state- the closest option was the headquarters of
the National Forest which appeared to be located in the capital of the state
the forest was located in, so I ran a query to select for forests where
headquarters was in Jackson, Mississippi. I quickly realized I really needed a
map with the Mississippi boundary so first I went and downloaded the National
Boundary Dataset from USGS but it wasn’t quite what I needed so I went back to
Mississippi GIS to try to find a boundary map. Success! In their MARIS database
I was able to download the Mississippi County Boundaries. At this point I had a
map with the Mississippi counties as well as the Mississippi National Forests.
I also downloaded and added a cities layer from the MARIS database. The cities
were polygons so I converted them to points. I then ran spatial queries to
narrow down my Mississippi map to only show the city of Hattiesburg and the De
Soto National Forest. After all of this it was just a matter of adding the
features I wanted on my map.
For the campsite map, I chose to display the possible campsites based on 5 different area sizes. I chose to customize the ranges because all of the other options (equal area, jenks, etc. Gave odd numbers. Basically I wanted to be able to easily see extremely small areas and extremely large and some in the middle but I wanted a round number for display purposes. I chose lighter colors for the smaller areas and increasingly darkening colors as the area got larger. I didn't want to choose colors in the exact same family because to me that makes it harder to differentiate between say a light light yellow and simply a light yellow when they aren't right next to each other.
I attempted to label road names to my main map of possible sites, but it was
very crowded looking, so then I tried to run a spatial query to narrow down to
only the longest roads, but they were among those that didn’t have names listed
in the attributes. I finally settled on running the intersect tool to isolate
roads that intersected with my selected campsite zones for labeling. I thought
this was necessary for people viewing the map to be able to orient themselves
and find the locations of the possible sites.
Here is my final map!
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