QGIS – Vector Data Layers Creation

  • Intro
  • Adding layers
  • Creating vector data
  • Adding vectors
  • Useful links

Information

Primary software used QGIS
Software version 1.0
Course QGIS – Vector Data Layers Creation
Primary subject 3D Modelling
Secondary subject Geospatial and Geographic Information Systems
Level Intermediate
Last updated November 11, 2024
Keywords

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QGIS – Vector Data Layers Creation 0/4

QGIS – Vector Data Layers Creation link copied

Vector data can be used directly to analyse geographical data, but it might also be useful to first compute new data like area data. The following tutorials show some analyses and computations that can be done with vector data.

Vector layer added to map canvas
Vector layer added to map canvas

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Adding layers link copied

When you first open the QGIS interface, the map canvas will be empty. In order to view items on the map, you will need to add some layers to the project. This tutorial will explain the basics of adding vector and raster layers to the map.

Related tutorials:

Background

Vectors and rasters are the two main types of data supported by GIS (Geographic Information Systems). Vectors represent geospatial data as geometrical shapes. Vectors can either be polygons, lines or points. Rasters, on the other hand, are made up of pixels rather than discrete geometrical shapes and are basically any type of digital image. For example, digital aerial photographs, satellite imagery or scans of maps. The differences between the two data types mean that vectors are generally better for representing discrete features, while rasters are better for representing data that varies continuously such as elevation or chemical concentrations.

Vector vs. raster data model
Vector vs. raster data model

You can see whether layers in a project are vectors or rasters by looking at the symbol next to the layer’s name in the layer list on the left of the QGIS interface. Rasters are symbolised by a checkerboard pattern. Vectors are symbolised depending on their geometry type: polygon (square with solid fill), line or point.

Adding layers: drag and drop method

The quickest and easiest way to add any type of layer to QGIS is by simply dragging the file from its computer folder and dropping it onto the the QGIS interface.

The more “official” methods for adding vector and raster layers are explained in the following sections.

Adding vector layers

This part of the tutorial will show you how to add a vector layer to your project. The most common file formats for vector data are: GeoJSON, GeoPackage and Esri Shapefile. This example will show how to load a GeoJSON file into QGIS, but the procedure is the same for any other vector file format.

Add vector layer via QGIS menu
Add vector layer via QGIS menu
  • Step 1: Obtain the data. In this example we will be loading a dataset from the city of Amsterdam into QGIS. If you want to follow along, download the GeoJSON file from the following site
  • Step 2: Open QGIS and navigate to Add vector layer….

    Alternatively you can click on the “Add vector layer” button in the side toolbar.

Layer
Add Layer
Add vector layer
Add raster layer via side bar button
Add raster layer via side bar button
Add vector layer pop-up window - browse to data location
Add vector layer pop-up window – browse to data location
  • Step 3: Choose the file path of the data you want to add to the project using the “browse” button.
Vector layer added to map canvas
Vector layer added to map canvas
  • Step 4: Click “add” and you will see the layer added to the layers list and the data displayed in the map canvas.

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Creating vector data link copied

As well as simply opening existing data using QGIS, you can also create your own vector data. This tutorial will explain the basic steps of digitising a raster map image, using an example from TU Delft campus. For more information on creating and editing vector data, see the useful links below.

Create a new vector dataset
Create a new vector dataset

Basic digitising

Step 1: Create a new vector dataset.

  • Open QGIS and create a new project.
  • Navigate to Layer » Create Layer » New Shapefile Layer…
    Click the … icon beside the file name field in order to set the file name and path.
Layer
Create Layer
New Shapefile Layer
  • Set the geometry type (polygon / line / point) from the drop-down menu. In this tutorial we will be creating a polygon vector layer.
  • Choose the coordinate reference system. In this tutorial we will be using EPSG:28992 – Amersfoort / RD New (the Dutch coordinate system).
  • Click “OK”.

 

Step 2: Add a layer to the project that can be used as a data source.

  • In this tutorial we will use an aerial photograph of the Netherlands as a data source.
  • The Adding WMS/WFS connections tutorial explains how to access the aerial photograph using QGIS.

Step 3: Navigate to the area that you would like to create a vector dataset for.

  • In this example we have navigated to the area around the TU Delft aula and library.
Enable toggle editing
Enable toggle editing

Step 4: Enable toggle editing using the digitizing toolbar.

  • Click on your vector layer in the layers list and then click on the yellow pencil icon in the toolbar. This will make the layer editable.
  • If you do not see the yellow pencil icon, enable the digitizing toolbar via Digitizing toolbar
    View
    Toolbars
    Digitizing toolbar
Add polygon feature
Add polygon feature

Step 5: Draw a polygon on the map canvas.

  • Click on the “add polygon feature” icon in the toolbar.
  • Click anywhere on the map canvas to start drawing a polygon.
Draw a polygon, right-click to finish editing. Click OK in the window that opens.
Draw a polygon, right-click to finish editing. Click OK in the window that opens.
  • When you are finished drawing the polygon, right-click and then click “OK” in the window that opens.
  • If you make a mistake while drawing, simply press “esc” and you can start again.
Save layer edits
Save layer edits

Step 6: Save the edits and stop editing.

  • Click on the “save layer edits” icon to save the polygon that you have added to the layer.
Polygon added to vector layer
Polygon added to vector layer
  • Click on the yellow pencil icon again to stop editing.

Digitising specific shapes

Shape digitising toolbar icons
Shape digitising toolbar icons

You can also use the shape digitising toolbar to precisely digitise specific geometrical shapes.

  • Open the toolbar via Shape Digitizing Toolbar
    View
    Toolbars
    Shape Digitizing Toolbar
Different options for drawing a circle
Different options for drawing a circle
  • Follow the same steps as above but draw a polygon using use one of the options from the shape digitising toolbar (instead of using “add polygon feature”).
  • For example, you can draw a circle using the 2nd icon from the left.
    You can use the drop-down menu beside each icon to see the options for drawing the different shapes.

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Adding vectors link copied

Network analysis


Network analysis can be used to find distances, travel times and shortest paths between two locations.  

Define the shortest and fastest path  

  • QGIS Training manual: “6.3. Network Analysis”
    you can access this manual using this link 
    Language(s): English 

    Chapters:

    • follow along: the tools and the data
    • calculate the shortest path (point to point)
    • try yourself fastest path
    • follow along: advanced options
    • shortest path with speed limit
    • service area (from layer)
    • in conclusion
    • what’s next  

Build a road network and define the shortest path between two points in the city of Washington DC

  •   Ujaval Gandhi: “Basic Network Visualization and Routing (QGIS3)”/”Basis netwerk visualisatie en routeren (QGIS3)”
    you can access the English tutorial using this link
    you can access the Dutch tutorial using this link
    Language(s): English, Dutch

    Chapters:

    • overview of the task
    • get the data
    • procedure 
       
       

Find out the facility with the least travel distance from each address in the city of Washington DC

  •  Ujaval Gandhi: “Locating Nearest Facility with Origin-Destination Matrix (QGIS3)”/ “Dichtstbijzijnde faciliteit zoeken met Origin-Destination Matrix (QGIS3)” 
    you can access the English tutorial using this link
    you can access the Dutch tutorial using this link  
    Language(s): English, Dutch

    Chapters:

    • overview of the task
    • get the data
    • procedure 
        

Define areas within 15-minutes of walking distance in the metro rail station data for Kochi, India

  •  Ujaval Gandhi: “Service Area Analysis using Openrouteservice (QGIS3)”/”Analyse Servicegebied met Openrouteservice (QGIS3)”
    you can access the English tutorial using this link
    you can access the Dutch tutorial using this link   
    Language(s): English, Dutch
     
    Chapters:
    • overview of the task
    • get the data
    • procedure 
         

Determine the travel times to a chosen location in the city of Bangalore, India

  •  Ujaval Gandhi: “Travel Time Analysis with Uber Movement (QGIS3)”/”Reistijd-analyse met Uber Movement (QGIS3)” 
    you can access the English tutorial using this link
    you can access the Dutch tutorial using this link
    Language(s): English, Dutch
     
    Chapters:
    • overview of the task
    • get the data
    • procedure 

Define the shortest path  

  • Erik Meerburg (3D geoinformation research group): “Urbanism GIS Course 16: Network analysis” 
    you can access this video using this link
    Language(s): English
     
    Chapters:
    • introduction (start-1:30)
    • geofabric download website (1:30-2:32)
    • OpenStreetMap (2:32-5:13)
    • network analysis (5:13-9:01)
    • open root service (9:01-end) 

Line length calculation and statistics 

Lines can also be analysed in QGIS. The length can be calculated and some statistics can be performed on them.   

Computation of the total length of railroads in the United States

  •  Ujaval Gandhi: “Calculating Line Lengths and Statistics (QGIS3)”/”Lengten van lijnen en statistieken berekenen (QGIS3)” 
    you can access the English tutorial using this link
    you can access the Dutch tutorial using this link
    Language(s): English, Dutch
     
    Chapters:
    • overview of the task
    • get the data
    • procedure   

Nearest neighbor analysis 

 

The nearest neighbour analysis allows to determine the features that are the closest to a given feature.

Determine the nearest populated place for each location where an earthquake happened

  • Ujaval Gandhi: “Nearest Neighbor Analysis (QGIS3)”/”Analyse Nearest Neighbor (QGIS3)” 
    you can access the English tutorial using this link
    you can access the Dutch tutorial using this link
    Language(s): English, Dutch
     
    Chapters:
    • overview of the task
    • get the data
    • procedure 

Use QGIS spatial statistics within the Processing Toolbox

  •  QGIS Training manual: “6.4. Spatial Statistics”
    you can access this manual using this link
    Language(s): English
     
    Chapters:
    • follow along: create a test dataset
    • creating random points
    • sampling the data
    • follow along: basic statistics
    • follow along: compute statistics on distances between points
    • follow along: nearest neighbour analysis (within layer)
    • follow along: mean coordinates
    • follow along: image histograms
    • follow along: spatial interpolation
    • try yourself different interpolation methods
    • in conclusion
    • what’s next  

Area calculation

 The area of a surface can be calculated.

Calculate surface area of polygons

  •  Hans van der Kwast: “Calculate Areas of Polygons in QGIS” 
    you can access this video using this link
    Language(s): English 
    Time: 1min 32s 
      

Compute area  

  • Erik Meerburg (Geogoeroe): “Oppervlakken berekenen” 
    you can access this video using this link
    Language(s): Dutch 
    Time: 13min 25s 
     

Compute total usable area of each building

  •  Erik Meerburg (Geogoeroe): “BAG: totaal gebruiksoppervlak per pand berekenen” 
    you can access this video using this link
    Language(s): Dutch 
    Time: 10min 15s  

Class percentages

 The percentage of features per class can be determined within polygons. 

Derive percentage of land use within polygons from CORINE 2018

  •  Hans van der Kwast: “Calculate percentage of land use per subcatchment in QGIS 3”
    you can access this video using this link 
    Language(s): English 
    Time: 17min 38s
     
    Chapters:
    • introduction (start-1:20)
    • style (1:20-2:15)
    • catchment polygons (2:15-3:00)
    • unique numbers (3:00-3:40)
    • catchment area (3:40-4:30)
    • more steps (4:30-5:15)
    • exporting (5:15-6:35)
    • expression (7:10-9:25)
    • dissolve (9:25-11:50)
    • intersect (11:50-12:40)
    • fix geometry error (12:40-14:00)
    • fix intersection error (14:00-end) 
       

Derive percentage of land use using the field calculator

  •  Hans van der Kwast: “Calculate Percentage Land Cover per Subcatchment in QGIS”
    you can access this video using this link  
    Language(s): English 
    Time: 3min
     
    Chapters:
    • introduction (start-0:20)
    • calculate percentage (0:20-1:30)
    • add class names (1:30-end) 

Street intersection density computations

 Street intersection density computations refer to determining the number of streets per area.  

Calculate the street intersection density for the city of Chennai in India

  •   Ujaval Gandhi: “Calculating Street Intersection Density (QGIS3)”/”Dichtheid van straatkruisingen berekenen (QGIS3)” 
    you can access the English tutorial using this link
    you can access the Dutch tutorial using this link
    Language(s): English, Dutch
     
    Chapters:
    • overview of the task
    • get the data
    • procedure 

Analysis tools from the processing toolbox

 The processing toolbox can also be used to perform spatial statistics. Basic statistics (e.g. mean, sum, median calculation) can be done, but also more advanced ones (e.g. nearest neighbour analysis).  

Use QGIS spatial statistics within the Processing Toolbox
 

  • QGIS Training manual: “6.4. Spatial Statistics”
    you can access this manual using this link 
    Language(s): English
     
    Chapters:
    • follow along: create a test dataset
    • follow along: basic statistics
    • follow along: compute statistics on distances between points
    • follow along: nearest neighbour analysis (within layer)
    • follow along: mean coordinates
    • follow along: image histograms
    • follow along: spatial interpolation
    • try yourself different interpolation methods
    • in conclusion
    • what’s next  

Height analysis

 The height of walls can be analysed by using a vector file with lines and Actueel Hoogtebestand Nederland (AHN) data, which contains the elevation data of the Netherlands. 

Height analysis based on lines and AHN data in Amsterdam

  •  Erik Meerburg (Geogoeroe): “Hoogte analyse kademuren in QGIS” 
    you can access this video using this link  
    Language(s): Dutch 
    Time: 24min 53s    

Population density analysis 

The population density can be computed and analysed.  

Population density analysis

  •  Erik Meerburg (Geogoeroe): “Is de Voorhof de dichtstbevolkte buurt van Nederland?” 
    you can access this video using this link  
    Language(s): Dutch 
    Time: 3min 37s