Creating vector data

Introduction

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.

Procedure

Basic digitising

Step 1: Create a new vector dataset.

Step 4: Enable toggle editing.

Step 5: Add polygon feature.

Step 5: Draw a polygon, right-click to finish editing. Click OK in the window that opens.

Step 6: Save layer edits.

Final result: Polygon added to vector layer

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.
• 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.
• This 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.

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 View » Toolbars » Digitizing toolbar

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.
• 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.

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.
• Click on the yellow pencil icon again to stop editing.

Digitising specific shapes

Shape digitising toolbar icons

Different options for drawing a circle

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

• Open the toolbar via View » Toolbars » Shape Digitizing Toolbar
• 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.

Useful links

• Module on creating vector data: https://docs.qgis.org/3.10/en/docs/training_manual/create_vector_data/index.html