CHLOROPLETH MAPPING IN GIS

 

 

Instructions:

Build a chloropleth map (using a given base layer) in ARC GIS for the lower 48 states only.  Using the data field and classification method of your choice, organize your data set into 5 classifications. Be sure the numbers in your legend make sense to readers.

 

Methods:

The base map we were given contained information from the 2000 U.S. census. By opening the properties within the 'counties' layer in the table of contents, I was able to open symbology at the top of the screen. From there I could choose any value from a dropdown menu to map. Also, under the quantities heading in the layers bar, I selected graduated colors (in accordance with the instructions)and then chose my color ramp on the main layer properties screen.

I chose to make most of the map in ArcGIS. I was able to add my legend, title, and explanatory material directly from ArcGIS using the Insert dropdown menu. In order to make this map well,
I had to locate more type options similar to what you have in Word and Adobe Illustrator. By choosing customize at the top of the screen I was able to locate the draw toolbar. This gave me more aesthetic options to choose from.

Challenges:
In order to normalize the data for readers of this map I had to manually change the range and the label for my 5 classifications on the main layer properties screen.

When I built my legend, there were unhelpful headings included. I had to cover them with something. By selecting the box symbol in the draw toolbar I had pulled down, I was able to hide the material. I then drew my own Legend Headings over the top of my box.

I tried inserting a light backdrop within ArcGIS. Unfortunately the color showed through the lighter colors on my chloropleth map. In order to resolve this, I exported my map as an Ai file and opened it in Adobe Illustrator. I placed a backdrop on my map in Illustrator only to notice the typed material from ArcGIS was missing. I had to go back to ArcGIS and export the file as a PDF in order for the typed material to be visible.

I chose not to include any explanatory material as this was not a subject I felt qualified to explain. Clearly I saw a pattern of older median ages in the midwest, and in retirement hotspots like Florida, parts of Texas, Arizona, and Nevada. I felt it better suited the map to allow readers to draw their own conclusions.