Understanding GIS Data and Making a Map

Lets start by loading some data.

In the folder ‘Tiwi_Training’ is the data for this tutorial. Skip to the video.

  1. In the browser window double-click on the layer ‘Tiwi_Boundary.shp‘.
  2. This layer will appear in the layers window. You can also see it displayed in the map window.
  3. You can turn on and off each layer by selecting and deselecting the tick boxes in the layers window.

Each vector data feature contains information about ‘attributes’ of that feature. In the case of the tenure data each feature is a bit of land with information about who owns it and how its managed. You can view information about each parcel of land using the information tool.

  1. Use the information tool to select (click on) some polygons to show their attributes.
  1. Explore the attributes for all the protected areas by opening the attribute table.
  1. Now open the Tiwi_Satellite_Image.png.
  1. Change the layer order: Drag the ‘Tiwi_Boundary’ layer above the satellite image layer in the ‘Layers’ window by selecting the layer then drag-and-drop

If you zoom in close you can see the individual pixels of the raster satellite image layer on the left. This is a raster data.

On the right in solid colour is the boundary layer. This is vector data.

  1. Select the ‘Zoom Full’ button to zoom to the full layer extent.
  1. Double-click on a layer to access its properties.

A ‘properties window’ opens. This window allows us to see information about the layer and change the way it is displayed. Explore the information by clicking on the different buttons on the left panel of the window.

  1. Change the symbology: Make the Tiwi boundary layer fill colour transparent so we can see the satellite imagery underneath. Select the ‘Symbology’ button.
  1. Select “Simple Fill” then “Fill Style” and set the fill style to “No Brush”
  1. Next change the outline or “Stroke Colour”: Click on the colour and another window ‘Select Stroke Color’ will open.
  1. Click on the wheel and then the triangle to select that colour.
  2. Finally press ‘OK’ and then ‘OK’ to see the result.
  1. Next add the ‘Tiwi_ClanGroups’ layer.
  1. Open the symbology properties window and make:·      
  • Fill style to no brush
  • In stroke colour set the opacity (Transparency) to around 40%
  • Stroke width to 1.6

Changing the opacity in the stroke colour selection window.

Move the ‘Opacity’ slider bar to ~40% then click ‘OK’

Click the ‘up’ button to increase the stroke width. Alternatively you could type in the desired width setting directly.

The symbology values should look something like this:

This produces a map where the boundary outline is broadly defined.

  1. Now add labels to the clan group layer.
  • Choose the label tab from the layer properties window
  • Set the type of label to ‘Single Labels’.
  •  Select the buffer option, to make it easier to see the labels then tick the ‘Draw text buffer’ option and change the buffer size if you wish. If you select the ‘Apply’ button at the bottom of the window you can check to see if the text is how you like it. When you are happy with the text; select ‘OK’ to finish.
  1. Add some place names using the Towns_Outstations layer.
  1. Change the town and places symbol to a white dot and change its size.
  1. Next add labels to the places in the same way that you added name labels to the clan boundaries.

The map is starting to look confursing with too many labels so turn ff the clan boundary layer by deselecting the tick box in the layer list.

  1. The satellite layer looks nice but it can be a bit distracting from other map information. You can reduce its prominence by adding some transparency in its layer properties ‘Transparency” setting.
  1. Finally add roads and tracks and make their line colour red. You should have a beautiful map that looks like this:
  1. At any time you can export your map for use in a document, presentation or even on Avenza maps as a geo-pdf.

Increasing the resolution of the image  will increase the size and detail of the output map.

Try exporting your image map at a couple of different resolutions.