Flowline Maps and Static Movement

The concept of depicting movement with a static, 2 dimensional map may seem counter-intuitive, but cartography has an answer to this problem- the flowline map.  Using lines and/or arrows of varying size/thickness to depict relative (or absolute, depending on the data) size or volume of whatever characteristic portrayed, flowline maps can also use the arrow and line placement to give an idea of the origination and destination of movement.

The relative sizes of the arrows in this map are proportional to the number of immigrants to the U.S. from each region, with the actual numbers in the legend in the lower right-hand corner.  The inset choropleth map in the lower left corner depicts the percent of the total immigrants to each state- the amount increasing with the darkness of the color shade.  At a glance the map viewer gets an idea of the relative volume and origination region of immigrants moving to the U.S., using a static, 2-dimensional map.  I used a drop-shadow effect throughout, to give a bit of figure-ground contrast and emphasis for the arrows, inset map and title, without making them stand out too much. The overall visual impression is one of relative 3-dimension and movement, using an entirely 2-dimensional space.