test 1 Flashcards
GIS
Geographic Information System
Features
Real-World Objects seen on maps represented by symbols.
Point
Feature with a position but no dimensions
Polyline
Feature with a length but no width
Polygon
A two-dimensional feature representing an area. Each vertex has coordinates.
Spatial Data
Mappable data (shape and size)
Attribute Data
Descriptive information or characteristics of the spatial features stored in an attribute table
Record/Row
On an attribute table, a single “row” of data. Each feature has a corresponding record.
Table
A set of data elements that has horizontal and vertical dimensions (rows and columns)
Field/Column
A column in a table. Each field contains the values for a single attribute in the table.
Metadata
Background information about the GIS data (who created it, when it was created, how it was created, how accurate it is, coordinate system, etc).
Database
Structured set of data stored on a computer that can be easily accessed, managed, and updated
Spatial Database
A database that also contains location data
Geographic Coordinate Systems
Coordinates based on Lat and Long, and measured in Degrees. Good for navigation over long distance.
Projected Coordinate Systems
Coordinates based on metres or feet. Good for local navigation and for measuring distances and areas.
Quantitative Problem Statement
A problem stated in measurable terms for GIS analysis.
Web Mapping Service (WMS)
Standard protocol developed by the Open Geospatial Consortium for serving georeferenced map images over the internet (ie GeoDiscover Portal).
File Geodatabase (.GDB)
ESRI propriety spatial database format. Stored as collection of system files in a folder. Can access different datasets within the same geodatabase.
Database schema
A series of standard database tables, column types, indices, and other database objects at the core of the geodatabase.
ESRI
Environmental Systems Research Institute
Field Data Types
The different attribute field types that are possible in a Geodatabase Feature Class (ie text, short integer, float, date, etc)
Text (data type)
Letters, numbers, special characters. (ie a-z, A-Z, 1, 2, 3, &, (, @, etc)
Short Integer (data type)
Whole numbers from -32,768 to 32,768 (uses 2 bytes)
Long Integer (data type)
Whole numbers from -2,147,483,648 to 2,147,483,648 (uses 4 bytes)
Float (data type)
Fractional numbers: precise to 6 digits, then rounded (uses 4 bytes)
Double (data type)
Fractional numbers: precise to 15 digits, then rounded (uses 8 bytes)
Date (data type)
Dates and/or times
BLOB (data type)
Binary large objects, including special feature types such as geodatabase annotation
Raster (data type)
Small images embedded into attribute table