QGIS » QGIS Application

This section is intended to show how to perform basic GIS operations in QGIS in the most straightforward way. It is modelled after “How do I do that in ArcGIS/Manifold?: illustrating classic GIS tasks”. That document illustrated a selection of tasks which were thought to be representative of common usage in 2004, and was itself derived from a checklist of essential GIS functions that was included in 1988 in “A Process for Selecting Geographic Information Systems”.

This document reflects the list of tasks found in the original "How do I do that in ArcGIS/Manifold?" document, and retains similar task titles and structure. A list covering additional tasks thought important, including these tasks, may be found in How do I do that in QGIS?

Introductory Notes¶

As much as possible these try and use the Alaska sample data. This means that if you want to try something, you can use see what things could look like.

• Introductory Notes
• Data Management
• Database Creation
• Data Manipulation and Analysis
• Data Display and Presentation
• Want to help?

Data Management¶

These relate to how to view and edit your tabular data.

• Adding a column to a table
• Sorting tabular or graphical data
• Calculating values for new fields using arithmetic or related tables - making calculations
• Relating data files and fields

Database Creation¶

This section details making and loading data for use in QGIS.

• Assigning topology
  • Digitizing
  • Identifying intersection points
  • Creating a polygon from line segments
  • Correcting topological errors
• Import and export
  • Importing database tables, raster data, and vector data

Data Manipulation and Analysis¶

• Data Retrieval
• Raster analysis: Select data by area masks
• Data Restructuring
  • Convert from raster to vector
  • Convert from vector to raster
  • Modify raster cell size by resampling
  • Data restructuring; changing raster values by selected area
  • Changing raster values by geographic feature
  • Reducing unnecessary coordinates - weeding
• Smoothing data to recover sinuosity
  • TIN from point data
  • Kriging from point data
  • Generate contour data from points
  • Generate contour data from raster
• Data Transformation
  • Mathematical transformation of raster data
  • Projection definition and coordinate transformation
• Vector overlay
  • Polygon in polygon overlay
  • Point in polygon overlay
  • Topological intersection
  • Line in polygon
• Raster Processing
  • Mathematical operations on one raster
  • Mathematical operations on two rasters
  • Neighbourhood functions
• Statistical function
  • Calculating areas, perimeters and lengths
  • Cross tabulation of two data categories
• General
  • Specify distance buffers
  • Polygons within distance of selected features
  • Find nearest features
• 3D Analysis
  • Generating slope and aspect
  • Identifying watersheds
• Network Functions
  • Choosing the optimal path through a network
  • Defining a drive-time zones
  • Geocoding addresses

Data Display and Presentation¶

• Map and map feature annotation

Want to help?¶

Feedback is welcome.
Notes on my-OS-does-it-differently and how-to-make-this-document-function-better are particularly welcome.

Or you can just pitch in and you'd be welcome.
Some guidance notes.

• Where possible try to use the Alaska Sample Data to demonstrate the examples.
• Any OS variation is welcome. I'm going to maintain a OS agnostic stance here, even though I know there are minor differences between menu layouts in linux, windows and mac.

• If you feel comfortable in the wiki-verse and have a login to the QGIS wiki I encourage you to add your changes.
• If you don't feel comfortable in the wiki-verse I'm happy for completed parts to be forwarded to me and I'll add them in when I have time.