Module 6B--Flow Line Mapping

This was an optional exercise that utilized Adobe Illustrator in total to produce a map that shows immigration by continent and by percentage to U.S. states.

The assignment was great practice using AI and developing flow lines. Once all the objects were placed on the map, I chose to separate my continents and place them in an arc around the inset map of the United States (which already displayed the states as a choropleth map using five manually derived classes.

The biggest portion of the exercise was actually drawing the flow maps and modifying them to an appropriate shape. This was easy using the line tool in AI and then manipulating the anchor points. The challenge was determining the stroke of the line, which was proportional to the amount of immigrants to the United States. In order to determine the stroke width, I used an Excel spreadsheet that provided the immigration numbers for each region. I then determined the proportional weight by first determining the square root of each region's immigration numbers. From there, I used the following formula:

Width of Line Symbol = (Size of Largest Line I Want) * (SQRT of Region Immig/SQRT Max Value)

Though it seems difficult, it was very easy using excel. The only challenge to this was for converging lines, where you split the difference of the lines so that they converge to the proper width. The only reason this was difficult for me was because I tried to use lines that had transparency adjusted. This caused an overlap which I could not remove. If the lines are solid, this is not an issue. Another consideration is to make sure the lines do not overlap other lines or terrain and are presented appropriately. I chose to build my flow lines in a new layer and then placed this layer below the continents layer so that the flow lines originated from behind the continent and stopped short of the inset map. I then changed the colors of the lines to match the color of the continents. 

Once the essential map elements were built, I then modified the flow lines to show an inner glow, a drop shadow, and a bevel. The lesson here was that in the appearance tab, the bevel and extrude effect had to be above the inner glow and drop shadow so that the bevel was on the line and not the other effects. I then adjusted the bevel to make them look three dimensional and in perspective.

A word of caution, many of these effects (especially 3-D) use a lot of memory, which can slow processes or reduce the ability to add new effects. To finish the map, I used file-export to export the map to a .png file.

Flow Map depicting 2008 Immigration Numbers by Region and Percentage to each State.
Projection: Winkel Tripel