GIS Terms List

Geography
GIS
An organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze and display all forms of geographically referenced information
Vector data
Consists of points, lines and polygons with attributes (name, population, area)
Point examples: school locations, burglaries, ATM locations, addresses
Line examples: Streams, roads
Polygon examples: Census tracts, county boundaries, tax parcels
Raster data
Consists of a matrix of cells or pixels organized into a grid where each cell contains a value. Example: Aerial photography
Geodatabase
“data warehouse”. Stores a collection of datasets (feature classes, tables, raster images)
File geodatabase
Can hold lots of data. Can be compressed. Recommended for use
Personal geodatabase
Limited on storage. Can’t share with others
Choropleth map
A map in which polygon areas are shown with varying colors to represent attribute values. The values are grouped into classes and each class is identified by a particular color.
Map elements
What goes on your final map. Legend, Scale bar, North Arrow, Title
Data Frame
Displays layers drawn on the map. The table of contents on the left side of the map shows the list of layers within that data frame.
Data Frame is REA. Can have multiple data frames but only 1 active at a time.
Data View
Use for exploring data. Real-world coordinates and measurements
Layout view
Use for creating map layouts. Add map elements in layout view. Size is in page units (inches)
GIS joins
Associate records in one table with records in another table through a common field.
Data table join
Both tables must have a field with the same values. The name of the field doesn’t have to be the same, but the data type has to be the same. (Numbers to numbers, text to text)
Spatial join
Use when map layers don’t share a common field. Joins attributes of two layers based on the location.
Group layer
Contains other data layers. Helps organized related data.
Tax Parcels <3600 is the Group layer. The other data is organized under the group layer

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