Boston Area Zip Codes and Highway
The map document is a representation of Massachusetts interstate highways and the zip codes they run through in the Boston area. The table of contents in ArcGIS is a tabbed list of data frames and layers on a map that shows how the data is symbolized, the source of the data, along with whether or not each layer is selective.
A data frame is a map element that defines the page extent, the geographic extent and other properties that consist of layers in the table of contents. A data-set can be represented in one or more data frames as well.
A map layer are groups of point, line, or polygon features representing a particular class or type of real-world entities such as population, roads, or postal codes. A layer contains the visual representation of each feature.
An attribute table is a data-set containing information about geographic features, usually arranged so that each row represents a feature and each column represents one feature attribute.
Black Communities in Boston Area
The map above is a representation of the black communities in the Boston area where graduated symbols represent the density of the back population.
Some issues that I explored on the Esri site are slow performance and after adding several data-sets to an ArcMap Data Frame, features in some layers do not align correctly with other layers. I have experienced the both issues addressed on the site as many others and it converts an easy task to a difficult one.