Guidance for arth Tool

Find out how different widgets work

Left Navigation Bar:

Plus Symbol – use this to zoom into the map.

Minus Symbol – use this to zoom out of the map.

Home – click to return to the default map view.

GPS – find your current location on the map. This requires the enabling of GPS location data in the dialogue box that appears automatically.

Right Navigation Bar:

Eye – open a small overview map in the corner of the screen, showing the current screen view in context on the global map.

Print – print out the current map view.

Chart – generate a chart of aggregated water risk for river basins or urban population for a selected area. Urban agglomerate areas or river basins are highlighted within the selected region.

Basemap gallery – select the basemap with which to overlay the additional water and population layers.

Chart Tool:

The chart tool graphs the projected population for a selected area on the map, or the aggregated water risk for river basins. Additionally, the areas of urban agglomeration or river basins within the selected region are highlighted on the map.

  1. Launch the chart tool by clicking on the chart icon. Next, select the feature to chart.
  2. Check the ‘Use spatial filter to limit features’ box, and then ‘Only features intersecting a user-defined area’. This brings up the polygon options shown above.


  1. Select a polygon with which to outline an area on the map. Once outlined, click ‘apply’ in the top right of the chart tool box to calculate the results for, and graph the area. To remove the shape from the map before it is applied, use the red bin icon.


  1. When ‘apply’ has been selected, this is the output. The chart results shows a graph of the urban population of the selected area, projected over 2010, 2020 and 2030. To see the exact population figure of a column, hover over it. The areas in orange highlighted on the map are the urban agglomerations in the area.


  1. To expand the chart, use the magnifying glass icon in the top right of the chart tool box.


This is how the same actions look with the river basin selection:


The yellow shapes outline the river basins in the selected area.



Anchor Toolbar:

  1. Layer list tool – select the layers to overlay onto the map. The available layers visualise water risk and urban population data.
  2. Legend – identify the meaning of the colours used in each layer.
  3. Geoprocessing – retrieve specific data of water scarcity risk for 2010, 2020 and 2030 for a selected location.
  4. Summary – see an overview of the screen in view in terms of the number of urban agglomerates and the population in 2010, 2020 and 2030.
  5. About – read information regarding the use and background of the Global Water Risk tool and some of the data sources used for the layers in the tool.

Basemap Gallery:

The Basemap Gallery tool allows users to change the map, and hence the associated features, for the background of the tool. The water risk and urban population layers are superimposed onto this basemap.

Here are some examples of the maps available:

Dark Gray Canvas: A basic map, separated along political boundaries and labelled by country, and up to town level when zoomed in. This is the default Global Water Risk Tool basemap.


Topographic: This is a map of terrain, showing geological features such as mountain ranges and lakes.


Imagery with labels: Detailed satellite imagery is combined with the labelling of urban markers to a very specific degree in this map.



Layer List Tool:

The layer list tool allows you to overlap the basemap with water risk and/or urban population maps. These are colour coded surfaces that display the general status of areas in terms of water scarcity risk and population size.

The layer list tool shows these options when opened. To add a layer to the map, select the box next to the layer name.


Urban population (2030): This layer outlines areas of urban agglomeration by 2030. It is activated upon zooming into a particular area, so it cannot be seen at default map view.


Urban population (2015): This layer shows the distribution of the urban populations on earth, and the size of the population is indicated by the colour of the pixel.


Water risk 2030: This is the central layer of the Global Water Risk Tool. It shows the probability of water scarcity by area in 2030. The severity of the risk is indicated by the pixel colours.


For the Urban population current and Water risk 2030 layers, the first layer title must be expanded by clicking on the small arrow to the left of the title. The subtitle that then comes up should be selected also in order for the layer to be loaded onto the basemap.

urban-population-layer-2-0 water-risk-layer-2-0

Geoprocessing Tool:

The geoprocessing tool is the main feature of the Global Water Risk Tool. This gives specific water scarcity information for a selected area in the form of a probability of water demand exceeding water supply between 2010 and 2030.


Launch the geoprocessing tool and select the polygon with which to select an area on the map.








Outline the required area with the polygon. To remove the polygon selection, use the red bin icon. When the correct area has been highlighted, click execute to generate the data.





The output looks like this. The sum column shows the total population in the selected area over 2010, 2020 and 2030 respectively.







Scroll down to see the table to water scarcity data. The mean column shows the average water scarcity risk over the selected area as a probability out of 1. These are for 2010, 2020 and 2030 respectively.

Summary Tool:

The summary tool shows overall data for the full extent of the screen. The output of the tool looks like this and is displayed directly above the bottom toolbar.


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