Databases Reference
In-Depth Information
The boundary data viewer
The boundary data viewer is a specialized viewer for comparing data measures
by geographic or political boundaries. Current boundaries supported are US
states, US congressional districts, US counties, three-digit US zip codes, and
five-digit US zip codes. The viewer also supports datasets containing both a
boundary component and a temporal component. For example, you may have a
dataset containing population by state (the boundary component) and by year
(the temporal component). If your dataset does not contain a temporal
component, then in order to use this viewer, a boundary identifier (state,
county, etc.) must be present, and it must uniquely identify observations in the
dataset. For example, if you want to compare data by state, then there must be
an attribute in the dataset to identify the state (state name, state abbreviation,
or state FIPS code) and there must be just one observation per state in the
dataset. If your data also contains a temporal component, then each observa-
tion in the dataset must be uniquely identified by a combination of the
boundary value and the temporal value. For example, if you want to compare
data by state from year to year, then there must be an attribute to identify
the state and a second to identify the year. The combination of state and year
must uniquely identify an observation.
Open the file DataByState.csv.
View the summary statistics for the dataset.
Notice that there are 52 rows in the dataset (it includes Washington DC and
Puerto Rico). The attribute named State contains the state name. There are six
other numeric data measures in the dataset that have abbreviated names. For
example, the attribute PcntCollegeGradOvr25 is the percentage of the popula-
tion over 25 years of age that are college graduates.
Close the summary statistics.
To start the viewer, drag the dataset to a display, and select “Boundary Plot”.
Before opening the actual viewer, you will be prompted, in a pop-up dialog,
to specify some parameter values that the viewer will need to organize the data.
See Figure 2.29.
The first requested parameter is the boundary for which your dataset
contains its data. For this dataset choose “State”.
The second parameter requested is the name of the attribute in the dataset
containing the boundary identifier. In this dataset choose the attribute
named State.
