GIS Flashcards
Define GIS
Geographic Information Systems.
A computerized system that store, manage, analyze, model and output geo-spatial and non-geospatial data according to the methods defined by the user to support decision making.
What are the key components of GIS? (5)
- Hardware
- Software
- Data
- Policies and approaches
- People
Give 4 GIS software.
- ArcGIS
- SuperGeo
- Quantum GIS
- GRASS
List GIS hardware. (4)
- Computers (VGA, RAM, Storage, Monitor, Input devices)
- Other peripheral devices (printers, plotters, scanners)
- Data computing devices (GPS, filed PCs)
- Mainframe/super computers
List methods and approaches in GIS. (6)
- Data input
- Storage
- Management
- Transformation
- Analysis
- Output
List some people involved in GIS. (5)
- Cartographers
- Data collectors
- GIS consultants
- GIS managers
- GIS analysts
What is data in GIS?
Data in GIS is made up of geo-spatial data.
- Geo-spatial data is spatial data related to the Earth’s surface.
- Line, point, polygon data
List ways data can be collected in GIS. (3)
- GPS receivers
- Drones
- Satellites
List some data input methods. (5)
- Scanning
- Digitizing
- Typing
- Importing and converting
- Through DBs
Name the two types of data models in GIS and give a brief introduction.
- Vector data model - represents geographical data using lines, points and polygons
- Raster data model - represents geographical data as a surface divides into a regular grid of cells.
Vector VS Raster Data Model (10)
Vector
- stores data as mathematical formulae
- smaller in capacity
- accurate representation of locations
- more suitable for discrete data
- less suitable for continuous data
- topology can be built easily
- effective for network analysis
- using algorithms is complex
- overlaying is less effective
- uses computer graphics to manipulate
Raster
- stores data in a grid structure
- larger in capacity
- less accurate
- less suitable to represent discrete data
- more suitable for continuous data
- topology building is complex
- less effective for network analysis
- using algorithms is less complex
- overlaying is effective
- uses image processing to manipulate
Spatial VS Geo-spatial data
- Spatial data - Data that can be represented on a space where it can be 1D, 2D, 3D, 4D
- Geo-spacial data - Spatial data that can be represented on the Earth’s surface.
What is a GCP?
What is the use of it?
- Ground Control Point - A specific place on the Earth’s surface with precisely known geographic coordinates.
- Help in geo-referencing by providing reference points that can accurately align spatial data to correct geographical locations.
What is geo-referencing?
Process of assigning real-world geographic coordinates to images.
