Spectrum - Custom Thematic Map

This document provides step-by-step instructions for adding a custom thematic map to an existing layer in Spectrum Spatial. In this example, the road centre line layer is modified so that roads are coloured based on their surface material type rather than by management ownership.

By default, the road centre line layer in Spectrum Spatial is coloured according to the road owner or managing authority authority. This guide shows you how to customise the symbology by applying a new thematic map based on a different attribute—specifically, the surface material type.

1. Open the Road Centre Line Layer

Locate the layer: Ensure the road centre line layer is visible in Spectrum Spatial.
Access options: Click the three dots next to the Rd centre line layer to reveal additional options.

2. Create a Thematic Map

Select "Thematic Map": From the options menu, choose the "Thematic Map" option.
Choose an attribute: Pick another column from the table. For this tutorial, select the column that contains the surface material type for each road.

3. Configure the Thematic Map

Mode: Select the "Individual" option.
Naming: Enter a name for the new thematic map (e.g., "Rd Surface Type").
Assign Colours:
- Click on the colour swatch for each unique value in the surface material type field.
- Choose your desired colours. For example:
  - Spray Seal: Your chosen colour.
  - Asphalt: Your chosen colour.
  - Gravel: A darker brown is recommended.
  - Concrete: A grey tone.

Important: Set the colours Exactly as desired, since changes cannot be made afterwards.

4. Apply the Changes

Save the configuration: Click "Apply" then "Create" to generate the new thematic map layer.
Layer visibility: You will now see both the original and new thematic map layers.
- Tip: Uncheck the original Rd centre line layer to view only the new thematic map.

Handling Blank Values

Observation: Some roads may appear with no thematic mapping if their surface material type attribute is blank (e.g., Department of State Growth roads).
Explanation: Roads managed by other entities (like the Department of State Growth) might not have the necessary attribute data and will default to the original colour.
Note: To change these, you might need to update the attribute values manually in your GIS data.

Conclusion

By following these steps, you can customise the symbology of the road centre line layer in Spectrum Spatial to reflect different attributes, such as surface material type.