Treading Gently Into QGIS
QGIS is a legitimate contender to dethrone Esri ArcGIS. Don’t believe it?
Here are 27 key differences between QGIS and ArcGIS to give you the incentive to give it a shot.
But really, the best part is that you require:
…To get started with this powerful software.
Without further ado:
QGIS Software Review
-Beautiful labeling options
-Wide range of GIS analysis tools
-Amazing data consumption
-Plugins help your customized tasks
-Graphical modeller is buggy
-No automatic topology error fixing
Write your own customized QGIS review below.
Where Can You Download QGIS Software?
QGIS can be downloaded from qgis.org. It’s available for all major operating systems – Windows 32 and 64 bit and also Mac.
When you start QGIS, you will see a large window called the map canvas. The map canvas will contain all of your map features.
The panel on the left is used to browse for and manage GIS data. Panels can be moved and docked at different locations.
Toolbars are located above the map canvas. Toolbars have different functionality and they can be undocked and moved where you’d like them to be.
As is the case with most software, a menu bar is at the top. It has drop-downs to control QGIS including Project, Edit, View, Layer, Settings, Plugins, Vector, Raster, Database, Web and Help.
When you save a QGIS, it will have a .QGS extension. This file type can be opened later similar to .TXT or .XLS file.
QGIS is making rapid strides forward.
QGIS is free and open source relying on volunteer efforts with huge support. Each version has improved since its debut in 2002.
Remember its name because it’s here to stay:
Quantum GIS 0.1In July 2002 Gary Sherman in Alaska starting writing open source QGIS 0.0.1 (pan, zoom, draw, line colors) (releases with pets on splash screen)
Quantum GIS 1.0January 2009 – Quantum GIS 1.0 (explore data, compose maps, create data, publish maps on the internet, Python plugins)
QGIS 2.0September 2013 - New vector API, integration of SEXTANTE geoprocessor, symbology and labelling overhaul
Have No Fear, the QGIS Plugins are Here
To quickly get started, this QGIS guide will show how you to download a QGIS plugin. There are about 500 plugins available in the QGIS repository. The number of plugins are growing every day to add even more functionality to QGIS.
Click Plugins > Manage and Install Plugins…
This will open your plugin manager. In the plugin manager, this where you can download, update, activate and deactivate them.
Let’s add some data to the map canvas:
Search for OpenLayers Plugin in the plugin manager. (The open layers plugin makes a variety of online data available to you). Click Install Plugin.
After this plugin is installed, it will be available to you in the top menu bar by clicking Web > OpenLayers Plugin.
You will see different layers to choose from including:
- OpenStreetMaps (Topographic, Cycle Map, Landscape and Public Transportation)
- Google (Physical, Streets, Hybrid and Satellite)
- Bing (Road, Aerial and Aerial with Labels)
- MapQuest (Open Aerial)
- Stamen (Toner, Watercolor and Terrain)
- Apple iPhotos (IPhotos Map)
Add a layer to the map canvas by selecting it from the drop-down menu. You can navigate in the map canvas using the pan and zoom tools. These tools can be found in the map navigation toolbar.
Scrolling the wheel on your mouse up and down will zoom in and out. Holding the wheel on your mouse down will pan left, right, up and down.
QGIS Plugins Examples
Make sure you take full advantage of QGIS plugins. Whether you’re looking to go 3D, build webmaps or classify satellite imagery, QGIS will supply you with a valuable collection of GIS-boosting functionality.
Visualize Data in the Three Dimensions
2D can be a bit lame at times. There I said it. The Qgis2threejs plugin catapults you to three-dimensions. This amazing plugin allow you to create an awesome 3D map in minute. After downloading and installing the plugin, here’s how to 3D visualize in QGIS:
Step 1: Download elevation data (DEM) from USGS Earth Explorer
Step 2: Add vector features or imagery to the map canvas.
Step 3: In the DEM tab, you can add vertical exaggeration to the DEM. In the point tab, add height to the map features.
Semi-Automatic Classification Plugin
Have you ever wanted to do supervised classification of remote sensing images?
The Semi-Automatic Classification Plugin is a QGIS plugin designed to process and classify multispectral or hyperspectral remote sensing images. A neat feature is that it can extract spectral signatures from the USGS Spectral Library , which is a set of spectral reflectance measurements of hundreds of materials in the lab.
Other QGIS Plugins
Displays QGIS view and features with attributes into Google Earth
Allows users to search for an address and get its coordinates
…and MANY more.
The Basics: Add, Create and Edit Vector Layers
Data creation, manipulation and updating is essential in GIS. This QGIS shows you how to do this with the Manage Layers toolbar. This toolbar allows you to add vector, raster and various other types of layers. You can also edit and create vector layers in Esri shapefile or SpatialLite format.
All you need to do to create a new shapefile is: Select the New Shapefile tool in the Manage Layers toolbar. From here, you can choose the feature geometry in points, lines or polygon. You can select the encoding and coordinate reference system too.
One difference that sets this apart from ArcMap is that you add attributes at this stage. Attribute data is information about your data in text, numbers or date format. You give your shapefile attributes a name, type (text, whole, decimal or date), width and precision. You can keep adding attributes by selecting the Add to attributes list button.
When you click OK, you will be prompted where and what name the new shapefile will be. After a shapefile is created, it will be added to the layer list in the left panel.
To edit a layer: Highlight the layer list and click the Toggle Editing tool in the Editor toolbar. This will enable the editing tools.
You add new nodes to geometry by clicking in the map canvas. To finish the geometry, you simply right-click in the map canvas. From here, you fill in the attributes and can save the geometry and attributes by clicking Save Layer button.
Adjust Symbols and Labels with Layer Properties
The layer properties is how you can change the style, labels, joins and even the metadata of your data. You can access your layer properties by either double-clicking the layer or by right-clicking the layer and selecting Properties.
On the left panel, there are tabs to change symbology, customize labels, modify joining tables and more.
In the layer properties, you can also create point, line and polygon symbols by adding several together. You can also adjust the transparency of features in the map.
In the labels tab, you can decide which labels to use. You can get surgical with labeling in QGIS. It’s not like any other GIS software. You can style labels with halos, transparencies, drop shadows and save it as a style file for later use. This is a high-level feature (similar to Adobe Photoshop) for beautiful cartographical output.
Export Images, PDFs and SVGs in QGIS Print Composer
In the composition panel, you can set the paper size, orientation, units and background color. Print composers are used to prepare maps for printing. To add a print composer in QGIS, click Project > New Print Composer. Give the new print composer a name.
To add your map in the print composer, select the “Add Map” tool. and drag an area in the canvas.
In the Item Properties tab, you can set the map scale, extents and even the rotation of the map.
The “Move Item” can move and resize the map window. The “Move Content” tool on the other hand, moves the geometry inside the map view.
The Layout menu gives the option to add labels, legends, scalebars, north arrows.All items can be adjusted in the item properties tab.
If you change something on the map, then you will have to refresh the view in print composer. To refresh your map in the print composer, click the “Update Preview” under the “Item Properties” tab.
Finally, to export a PDF map in QGIS: Click Composer > Export as PDF. If you export as SVG, this gives you the option to import the map in Adobe Illustrator and update further. You can also export the map in a wide variety of image formats including JPG, PNG and TIF.
Process Data Like a Boss with QGIS Geo-algorithms
It’s essential this QGIS guide gives the lowdown on all the readily available tools in QGIS. And there’s no shortage of tools straight out-of-the-box.
The easiest way to find a GIS processing tool is searching for it. At the top of the processing toolbox, the search bar enables you to locate the tools you need. There are over 600 tools available in the processing toolbox:
The Geoalgorithms are grouped into separate categories:
DOMAIN SPECIFIC TOOLS are discipline-specific tools like cost analysis, geostatistics, hydrology, terrain analysis, viewsheds and lighting.
IMAGES TOOLS is to manipulate, calibrate, analyze and segment satellite and aerial imagery.
RASTER TOOLS are designed for analysis, creation, filtering and generating statistics with raster data sets.
RASTER – VECTOR TOOLS are tools used for either the conversion or raster to vector (or vice versa) and tools used combining the use of raster grids and vector files.
VECTOR TOOLS is a mammoth collection of tools for analysis, creation, geometric overlay, statistics, table and selection algorithms for vector points, lines and polygons.
The most common GIS processing tools like buffering, clipping and unions can be found in vector and raster menu.
The QGIS processing toolbox can be accessed through the Processing menu item. In the processing menu, there is a graphical modeller – similar to ArcMap’s model builder interface. The graphical modeller assists users automate a sequence of operations and GIS processes.
QGIS Open Source: A Voluntary Project
In this QGIS guide, we covered all the essential information. From adding GIS data to creating it… from adding plugins to processing data with geoalgorithms… from symbolizing points, lines and polygons to exporting maps in print composer. You now have all the essential tools to maneuver yourself around in QGIS.
You can now sit in the driver’s seat, with a roadmap in hand, GPS on the dash, and put yourself in cruise control… using this QGIS guide.
QGIS succeeds in a big way because it’s an open source project. Volunteering developers stand by their product with pride.
People are encouraged to donate to the QGIS project and support the dedicated team of volunteers and organisations.
Now, it’s your turn:
We’ve provided you a blueprint for QGIS open source software. But this QGIS guide has just scratched the surface. Download QGIS today, leverage its tools and map with confidence.