An Introduction to Quantum GIS · PDF fileWhat is Quantum GIS? •Developed in 2002 and...
Transcript of An Introduction to Quantum GIS · PDF fileWhat is Quantum GIS? •Developed in 2002 and...
An Introduction to Quantum GIS
Lachlan Smeed, QUT
What is Quantum GIS?
• Developed in 2002 and undergone significant development.
• Open source, community driven geographic information system.
• Runs on Linux, Windows and/or MacOS.
• Fully functioning desktop geographic information system.
Features of QGIS• Features of QGIS include;
• Importing data from multiple sources
• Digitizing
• Editing
• On the fly reprojection
• Geoprocessing
• Database connectivity; and
• Raster processing
• Professional and easy print layout function
• QGIS is a free program
• Very user friendly
• Simplified version of expensive GIS based software
• Program negotiation is straight forward
• Help tips for new users
• Professional layout opportunities
• Works on laptops
Benefits of QGIS
Data Capture
• Queensland Spatial Portal and Queensland Government Information System
• A large free spatial database
• Thousands of datasets relating to Queensland and individual regions
• Easy to negotiate for appropriate data
• Metadata normally attached to data for ease in later analysis
Importing Data• QGIS is able to import multiple data sets, including;
• Vector and Raster
• Post GIS tables
• Databases
• MSSQL tables
• WMS and WCS server layers
• Layer creation from a deliminated text file
• Creation of new spatialite layer
Raster Data Source
• USGS Earth Explorer, a site for free raster data
• Contains Large amount of;
• Landsat Imagery
• Aerial Photography
• Heat Signature data; and
• Much more data
• Raster data require georeferencing
• USGS provide metadata showing coordinates
Plugins and Georeferencing• QGIS requires the
installment of the Georeferencer plugin
• Georeferencer is a free QGIS plugin
• Requires the coordinates of the corners of raster image
• Makes vector and shape files match up appropriatley.
• Vector data and shape files require geographic datum of Australia (GDA 94)
Filtering Features • To get selected vector layer
or shape file features filter equation required
• Filter equation much like that of a query equation in ArcGIS
• Example;
• A filter equation was used to show the only town feature named Roma
Print Composer • QGIS tool to present maps on paper
• There are three main types of map projection
• These include;
• Cache
• Rendering
• Rectangular
• Cache- Prevents movement of map, allows zooming only
• Rendering- Movement of map around like main window
• Rectangular- Displays ‘Map Printed Here’ only
Features of Print Composer
• Easy creation of professional map layouts and presentations
• Essential map features and secondary maps
• This Includes;• A scale bar
• Legend
• Title
• Orientation Features
• Ability to insert custom images, change paper size, background colour, orientation and measurement units.
• Ability to export images as JPEG, PDF and SVG file types
Example Map SeriesSurat Basin, Queensland
Benefits of QGIS
Students Professionals
• Detailed analysis of specific data
• Simplified version of other complicated GIS software
• Easy to understand• it’s free
• Detailed analysis of specific data
• It’s free• Development of more in-
depth and detailed programs
• Extended analytical opportunities
• Advanced mapping opportunities
Any Questions?