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 Glossary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A
Adhoc data - Calculated data that is created by application of a mathematical or logical tranformation in the Analyzer.
B
C
Choropleth Map - A choropleth map is a map which shows regions or areas which have the same characteristics. Each area (county) is shaded according to the data. Technically, a choropleth map is based on a stepped statistical surface.
Conditioning - A primary dataset is conditioned on secondary data when conditions are imposed on the secondary data that slice the primary data. This is used to look for interactions between the datasets.
D
Data Cube - A collection of datasets having a common Topic, or theme. The Data Selection Box consists of several data cubes.
Data filter - This is a tool for subseting one dataset by conditioning it on another using inequalities to slice the data. This is done in DC Maps using sliders.
Data interaction - The interaction between two datasets can be visualized on a map by spatial correlation or dependence, or lack of it
Data Selection Box - The hierarchical data tree to the left of the choropleth map from which datasets are selected. The Data Selection Box contains data cubes which contain one or more datasets.
Data Set - A collection of data items.
Data Item - A single unit of data.
Data Warehouse - The data warehouse gathers all the information from the various legacy systems.
DC Maps - Dynamic Choropleth Maps.
Dimension - A measure of spatial extent. The dimensions of a data space is determined by the number of variables in the multidimensional vector forming that space. DC Maps operates in a five dimensional space in which two dimensions are spatial and three dimensions are data.
E
F
FedStats - The gateway to statistics from over 100 U.S. Federal agencies (see http://www.fedstats.gov/).
G
Geo - Earth, Geography: Geospatial
GIS - Geographic information system.
H
I
Information - is what a person uses to understand reality, or an abstraction. Information is conveyed efficiently by use of maps and charts that tell a data story.
Interactive - DC Maps allows a high degree of user interaction by its use of software Interface components such as Sliders, Zoom facility, Popup Menus, drill downs, floating legends, check boxes, data trees, and buttons.
J
K
L
M
Metadata - Data about data.
N
O
Office of Environmental Information - Helps ensure that EPA collects high quality environmental information and makes it available to the American public (see http://www.epa.gov/oei/). We provide guidance to assist the agency about the way we collect, manage, analyze and provide/allow access to environmental information. By fulfilling these activities we expect that the public and policymakers can make informed decisions.
P
Percentiles - When data is sorted in ascending order the percentiles are those data items which cut the data into 100 bins of equal frequency.
Principal data - The main dataset used to color the map, as compared to the data used to condition (filter) the principal data.
Q
R
S
Slider - A software interface control that allows the user to interact with the map.
Spatial analysis - The study of such constituent parts relating to space or a space.
T
Toxic Release Inventory (TRI) - A publicly available EPA database that contains information on toxic chemical releases and other waste management activities reported annually by certain covered industry groups as well as federal facilities. This inventory was established under the Emergenct Planning and Community Right-to-Know Act of 1986 (EPCRA) and expanded by the Pollution Prevention Act of 1990 (see http://www.epa.gov/tri).
Transformation - A mathematical or logical operation on data to produce calculated data.
U
V
Variables - A name used to represent data.
Value - The content of a data item. A number.
Visualize - In an image context, the eye-brain perception of the information that the image conveys.
W
X
Y
Z
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