Digital Earth Australia (DEA) Wetlands Insight Tool (QLD)

The data developed via the Wetlands Insight Tool presents a combined view of Water Observations from Space, Tasseled Cap Wetness and Fractional Cover measurements from the Landsat series of satellites for each palustrine and lacustrine wetland in the Queensland wetland mapping*. The data is summarised as a series of hydrological attributes and visualised as stacked line plots.

Please note

The DEA Wetlands Insight Tool is based on remotely sensed satellite imagery and requires field validation so care should be used when interpreting results as increases/decreases in cover types can (1) conflate technical limitations with on-ground change, and/or (2) be associated with different processes. For example an increase in green cover could indicate canopy recovery of desirable wetland species or an increase in the presence of invasive weeds.

Data quality may vary. The stack line plot will display periods of low data quality (defined as less than 4 observations in a 6 month period) as pale overlays. An attribute on data quality has also been provided in the mapping data to indicate data quality. The period between when Landsat 5 ceased operations (November 2011) and Landsat 8 data became routinely available (May 2013) has been identified in the stacked line plot as a low data quality period. The 30-metre resolution of Landsat imposes an intrinsic limitation on the Wetlands Insight Tool.  Wetland areas that are small, or long and narrow in nature are likely to be inaccurate (due to inclusion of neighbouring non-wetland pixels) or difficult to interpret (stack line plots for areas with a small number of pixels have sharp steps in them).

For more information - see Wetlands Insight Tool: Characterising the Surface Water and Vegetation Cover Dynamics of Individual Wetlands Using Multidecadal Landsat Satellite Data.

How to use - WetlandMaps

To access hydrological attributes and the stacked line plot

1. Open WetlandMaps
2. Zoom to your area of interest within Queensland (performance will be affected if viewing the layer on a large scale)
3. Tick the box next to “Queensland Wetland Mapping" > "Wetland Data Version 6.0 - areas"



 

4. Click on a lacustrine (indicated by hatched or non-hatched yellow polygons) or palustrine (indicated by hatched or non-hatched maroon polygons) wetland to open the information pop-up box
 


 

5. Scroll through the attributes to find those related to wetland hydrology including permanence of water, residence time, and residence extent. Please note, additional attributes may be available when the mapping data is downloaded from QSpatial and viewed in GIS software.
6. Click on the “Display wetland hydrology” button as seen below:
 



 

7. This will open a new window displaying the stacked line plot chart, at the bottom of the screen, for that specific wetland:



 

* Note that a minimise size threshold is applied due to limitations in the spatial resolution of satellite imagery.

How to use - WetlandSummary

WetlandSummary contains a stacked line plot chart for every area of interest provided (such as Local Government Area, or Drainage Basin). The stacked line plot charts display the amount of open water, wet, green vegetation, dry vegetation and bare soil over time within each wetland. For WetlandSummary, the stacked line plot charts visually represent all the wetland areas in the area of interest.

The stacked line plot charts have an interactive slider that helps to display the chart with the wetland size of interest (for example, to omit large structures like dams). This allows the user to understand the open water within the identified wetlands of an area (termed fractional cover). The stacked line plot charts can be used to visualise droughts, major hydrological events, floods and how water in wetlands is changing over time.

To access hydrological attributes and the stacked line plot:

1. Open WetlandSummary and choose an area of interest.



 

2. Scroll down the page to the stacked line plot chart. Adjust the sizes as needed to see results for the size of wetlands of interest.


 

3. The stacked line plot charts can also be separated by area in hectares of wetland sizes to easily compare the fractional cover amounts between different types and sizes of wetlands (small, medium and large). This allows the user to set their own thresholds for small, medium and large wetlands. To do this, click on the link below the chart that says Show comparison charts.
4. Use the two slider options on the top and bottom of the slider on the right of the chart. Moving the top slider around will set the small wetland size range, and the bottom slider will set the large wetland size range. The middle chart will automatically show wetland sizes between the large and small custom size. See below for an example with <5ha as the small range, and >500ha as the large range.

Please note the stacked line plot charts are a data visualisation tool - any analysis of this data should be undertaken using the source data from GeoScience Australia.

DEA Wetlands Insight Tool - Notebook

Geoscience Australia has published a Github notebook page with instructions on how to generate customised charts based on an area of interest.

References

1. ^ Dunn, B, Ai, E, Alger, MJ, Fanson, B, Fickas, KC, Krause, CE, Lymburner, L, Nanson, R, Papas, P, Ronan, M & Thomas, RF (April 2023), 'Wetlands Insight Tool: Characterising the Surface Water and Vegetation Cover Dynamics of Individual Wetlands Using Multidecadal Landsat Satellite Data', Wetlands. [online], vol. 43, no. 4, p. 37. Available at: https://link.springer.com/10.1007/s13157-023-01682-7 [Accessed 11 October 2023].

Last updated: 11 October 2023