This map arose from a GIS project on sinkhole development. I created during that time, but really did nothing special to it. It was created to display the varying density of caves in the state of Missouri. so that I might observe their relationship to sinkhole development.
The data for this map were collected from the Missouri Spatial Data Information Service (MSDIS), and it seems just in the knick of time. The shapefile I had originally downloaded is no longer available from their service. Fortunately, there is not much of a contrast between the sinkholes and caves. They both pretty much exist in the same circumstances.
The manner in which this map was created is slightly fascinating to me. Essentially, it displays the spatial join of a County shapefile and a Cave Density by Quadrangle polygon (not points) shapefile. MSDIS indicated that the reason the Cave Density file is shown in this manner, to protect the locations of private and dangerous caves. Regardless, the two files were joined, and I chose a dot density format for display. Initially, I did this just to see if the software would do it. After I discovered that it would, I played with the density options, and discovered that I could “mask” the dots to the original quadrangle file, for a greater degree of accuracy. Indeed, I perceive it to have done just that, and the distribution appears to be very similar to sinkhole locations.
While struggling to figure out what I was going to do for this assignment, I rediscovered this map, but was at a loss as to how to spice it up. I tried several things, inserting lakes, rivers, cities, etc, but nothing really seemed to fit with this map. It was almost as if it demanded to be left in its most raw format. Consequently, I decided it would be a simple and basic cartographic display of dot density, by county; and actually, by quadrangle.
I choose the color for the counties because it is somewhat of a standard color in maps of this type. It is non-intrusive to the data, and not distracting in the least. Actually, it was simply “beige,” but I decided that even that was too much of a glare, and imposed a 50% transparency. The only other item I could think to add to the map was the county names, for better location comprehension.
Stepping outside of the usual choices, which I had made in other maps, for scale and north arrow; I chose something just a little different. The north arrow, with a simple northern indicator was really all that was needed, and it was obvious. However, my own choice of scale bar surprised me in its effectiveness. By dicing up the division in the intervals that I did, and the alternating “low/high” effect it has, created a simple scale bar that is very easy to visually translate to the map, without having to pinch your fingers together, or get out a ruler. The remainder of the map is simply title and data credits. The projection was also added, as Transverse Mercator, likely the best projection for the state of Missouri. The only issue I had, which I still do not care for, is the legend.
I found the legend be particularly annoying. Every time the legend is moved, the dots move around inside the box. That is not so much the problem, as ArcGIS forces the user to have an extra unnecessary item, that which the dots represent. It seems enough to have “1 dot = 5;” I can always tack “caves” to the end of that with the built-in tool set. I do not see the necessity for that, but perhaps I do not understand it enough, or I am completely missing how to rid myself of that extra line. In either case, I could have easily erased it in Photoshop, but thought that it might have some significance that I was missing.
Finally, I noticed that the map did not really fit the page nicely, no matter where I placed the elements. Ultimately, I decided that it would be a square sheet, for no other reason than to contain all of the elements more nicely. In addition, as with every map, the final product was created ready for press, in 300 dpi JPG image format.
Overall, with an understanding of how it was created, I find this to be an interesting map and would be very curious to know how accurate the dots are in relation to actual cave sites.
GGP330 - Cartography
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