Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

Introduction to using QGIS

December 8, 2015

Contents

1 Introduction 2

2 Getting familiar with the Interface 2

3 Adding a layer 3

4 Attribute data 54.1 Viewing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54.2 Selecting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.3 Editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5 Symbology/Styling 85.1 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85.2 Labeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

6 Additional Resources 10

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

1 Introduction

This lab session will be a basic Introduction to QGIS. We will see how to addand view map layers, view and edit its data, various styling options availableand how to create printable maps.

2 Getting familiar with the Interface

Figure 2.1: QGIS Interface

As can be seen in the figure, the QGIS interface has five major components-

• Menu: It provides access to various QGIS features including all the func-tions and plugins in the form of an orderly dropdown menu.

• Toolbar : It provides easy one click access to more commonly used QGISfunctions. This toolbar can be customized easily as per the user’s need.

• Map Canvas: It provides a dynamic run-time visualisation of the layersloaded and active in the layer list. Any operation performed is instantlyreflected int the map canvas.

• Layer list : Contains the list of layers currently open in the project. Also,the order in which they are listed conforms to the order of the renderingon the map canvas.

• Status-bar : This part of the interface provides vital information regardingthe view on the map canvas. It shows the co-ordinates wherethe mousepointer is, the scale of the map as well as the projection system in whichthe map is being rendered.

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

3 Adding a layer

To add a layer in QGIS, either -

• Go to Layer option in the Menu and select Add Layer → Add VectorLayer.

• Or, Select the option Add Vector Layer from the toolbar.

Figure 3.1:

In the pop-up window, browse and select the shapefile1 (with a .shp exten-sion) and click open. Now the layer can be seen in the ‘Layer List’ as well asits visualisation on the canvas.

A few important tools related to the map canvas -

• Pan: Move the hand-shaped cursor over the MAP view, then click anddrag to PAN the map. Letting go of the click button will set the mapview the new position.

• Zoom: There are multiple options for zooming.

– Zoom-in

– Zoom-out

– Zoom to the extent of the layer

1Credits : Western Ghats SDI portal (http://wgsdi.kaiinos.com)

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

Figure 3.2: Add layer

Figure 3.3: Pan

Figure 3.4: Zoom In and Out

Figure 3.5: Zoom to layer extent

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

4 Attribute data

4.1 Viewing

To view the attribute of a layer, right click on the layer from Layer list andclick on the option Open Attribute Table. Alternatively the same option can beaccessed from the Toolbar menu.

Figure 4.1.1: Open Attribute table

Figure 4.1.2: Attribute data

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

4.2 Selecting

These attributes correspond to the vector features and are used to describethem. To see which feature is being described by an attribute, we can select arow and the corresponding feature is highlighted in yellow on the canvas.

Figure 4.2.1: Selecting Attributes

Another way of selecting features is through Select features using Expression.Also, the toolbar menu provides various options to select features by clicking onthen on the map canvas.

Figure 4.2.2: Select options

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

4.3 Editing

Before editing the data, first enable the editing mode by clicking on ToggleEditing button.

• To add a new column, click on the New Column button and fill in therelevant entries.

Figure 4.3.1: Add a column

• To edit the attribute values just double click on the respective cell.

Figure 4.3.2: Edit Attribute data

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

Make sure to save the edits and click on the Toggle Editing button to avoidaccidental edits.

Figure 4.3.3: Save edits

5 Symbology/Styling

In this section we’ll see how to visualise the maps in a different manner basedon their properties. For viewing the styling options, right click on the layer andgo to Properties → Style. There multiple viewing and styling options can beseen.

5.1 Classification

We can classify different features of the layer based on the attribute data.

• Categorized : This is useful when a paritcular column describes a groupor category in which the feature belongs. Example: State name, District,Land use.

• Graduated : This option is useful when we we want to classifying in inter-vals of some numeric attribute value. Example: Area, Population.

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

Figure 5.1.1: Categorized

Figure 5.1.2: Graduated

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Western Ghats Biodiversity : Capacity Building Workshop8th-19th December, 2015

5.2 Labeling

QGIS provides an option to label the features of the layer based on its attributedata. This option can be accessed from Properties → Labels.

Figure 5.2.1: Labeling

6 Additional Resources

• QGIS training manual - Module : Interfacehttp://docs.qgis.org/2.8/en/docs/training_manual/introduction/

index.html

• QGIS training manual - Module : Creating a Basic Maphttp://docs.qgis.org/2.8/en/docs/training_manual/basic_map/index.

html

• QGIS training manual - Module : Classifying Vector Datahttp://docs.qgis.org/2.8/en/docs/training_manual/vector_classification/

index.html

• Working with Attributeshttp://www.qgistutorials.com/en/docs/working_with_attributes.

html

• Basic Vector Stylinghttp://www.qgistutorials.com/en/docs/basic_vector_styling.html

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