DEA Waterbodies User Guide
Your guide to Digital Earth Australia (DEA) Waterbodies
Published:11 February 2021
4. Select ‘Surface Water’, then ‘Digital Earth Australia Waterbodies’. Click on the plus symbol, or the blue ‘Add to the map’ button on the top right corner of the popup to load the data into the map.
5. You will now see a map of Australia with blue waterbodies plotted on it.
6. You can scroll in and out of the map using the scroll wheel on your mouse. Drag the map around to reposition it. There are also navigation tools down the top right hand-side of the map window. If you want to return to this view of all of Australia at any time, click the ‘zoom to extent’ button on the left-hand legend panel.
7. You can get a time series of the change in the percentage of total surface area observed as wet for each waterbody. To get this time series, click on the waterbody you want to explore. Once you’ve clicked on a waterbody the outline of the waterbody you have clicked will turn white, and you will see a pop-up window with a preview of the time series.
8. The pop-up window contains important information about the time series data, and provides a preview of the time series.
9. If you would like to explore the data in more detail, click on the blue ‘expand’ button in the pop-up window. This will open up a graph along the bottom of the screen, and will add an entry to the left-hand legend panel. If you want to download the data within the time series, click on the blue down arrow in the pop-up window.
10. If you hover your cursor over the graph that opens at the bottom of the page, a pop-up window will show you the values of the graph at each observation time step. Note that the graph draws a straight line between subsequent observations; you can see where valid observations actually exist by hovering your cursor over the graph and moving forwards and backwards in time.
11. There are two time series available for each waterbody, which can be seen in the legend panel on the left-hand side once a waterbody has been selected, and the time series expanded:
- 'Percentage of total surface area observed as wet': the percentage of the total surface area of the waterbody that has been classified as 'wet' for each time step. (Note: this is not a volume)
- 'Wet Pixel Count': the total number of pixels that have been classified as 'wet' for each time step. This value is useful if you need to calculate an area of wet pixels. Each pixel is 25 metres by 25 metres.
You can toggle these different time series on and off by clicking on the square boxes next to the names.
12. If you want to compare two different waterbodies, you can use your mouse to find the waterbody you want to add to the time series, click it, click on ‘expand’ in the pop-up window, and it will be added to the existing plot.
The colour of the dot on the map (here green or orange), corresponds to the colour of the time series in the graph at the bottom of the page, and the colour of the text in the left-hand legend panel.
You can easily remove time series from the graph at the bottom of the page by either switching them off by clicking the square next to the ‘Waterbody’ label, or by removing it completely from the graph by selecting ‘Remove’.
13. If you would like to download the data within the graph window at the bottom of the page, click on the ‘Download’ button on the top right of the graph window. This will download all of the time series you have currently plotted in the graph as a .csv file.