PORTAL USER GUIDE
Choropleth (Custom Ranges)
The Choropleth (Custom Ranges) tool allows you to specify the values that define the upper and lower limits of the intermediate classes of your “classes” or “bins” that show up on the legend of your map. All of the other classifiers calculate where these breaks lie, based on the different classification method.
The only limitation placed on you is that the lowest limit of the lowest class cannot be lower than the lowest value in your dataset, and the highest limit cannot be higher than the highest value.
For this worked example, we will look at the distribution of Gini Coefficient values across Victoria’s SA2s in 2016.
To do this:
- Select Victoria (ste/2) as your area
- Select NATSEM – Social and Economic Indicators – Synthetic Estimates SA2 2016 as your dataset with the following variables:
- SA2 Code
- SA2 Name
- Gini Coefficient
Once you have added this dataset, you are ready to create your Choropleth. Follow the inputs instructions below to see how to do this.
Now that you have added your datasets you are ready to create a Custom Range Choropleth map.
To do this, click on the Choropleth (Custom Ranges) tool (Interactive Maps & Charts → Mapping Areas/Polygons → Choropleth (Custom Ranges)) in the Visualise pop up window (shown below). This will bring up a range of fields that need to be populated. Enter your parameters as you see them below.
There is an additional step for these parameters shown in the pop-out box. These are explained with the other parameters below
- Select a dataset: Here you can choose which of the datasets you would like to display as a map. Select NATSEM – Social and Economic Indicators – Synthetic Estimates SA2 2016.
- Select an attribute: This is the field that you want to map. If you want your map to make sense, and actually display the variable you are interested in, it is important to make sure you have selected the right attribute to map together with right classifier. Select Gini Coefficient.
- Import parameters from: This allows you to bring in the classification parameters from another layer in your session. This is useful if you want to be able to compare two map layers using the same classification. Select None.
- Number of Classes: This slider allows you to define the number of breaks in your data (minimum of 3, maximum of 12). The number that you choose should depend on the distribution of your values, the number of data points (areas) and the information that you are trying to portray with your data. Select 5.
- Class ranges: This will open up the pop-up box as shown above, which allows you to edit both the values which specify your legend “bins” or “classes”, as well as the names of those bins. Rename them Lowest, Second Lowest, Middle, Second Highest, and Highest. Select the bins to be 0.28, 0.31, 0.35 and 0.38.
- Select a palette type: Here you can choose the type of colour scheme for your data. Select Sequential. The other options are listed below:
- Sequential: Which shifts from a shade of one colour to another;
- Qualitative: Where the colours are unique along the palette (used for Pre-classified); and
- Diverging: Where colours shift to two colours from a central point along a natural spectrum
- Palette: This allows you to choose the actual colours of your palette (you can switch the ends of the palette around by clicking the Reverse Palette box at the bottom of the box. AURIN uses colours generated by Colour Brewer. Select Greens.
- Default Opacity: This slider allows you to define how opaque your map is over the base map. 0.00 indicates completely transparent, 1.00 indicates completely opaque. Select 0.5.
- Hover Opacity: This slider allows you to define how opaque you want specific areas to be when you hover over them with a mouse, with the same values as for Default Opacity. Select 0.85.
- Stroke/Line Opacity: This slider allows you to define how opaque your polygon borders will be, with the same values as the Default and Hover Opacity. Select 1.0.
- Reverse palette: This reverses the order of the colour in its palette which may be useful if you want its colours on opposing ends. Untick this box.
- Hide Null Values: This will not give a class to any null values if they exist in your dataset. Untick this box.
- Save Visualisation as: The default for this field is “[Attribute] -1” It’s a good idea to change the name of this to something that reflects the data, particularly if you plan on having multiple choropleth maps from different datasets. The name that you choose here will also be displayed in the legend automatically generated for your map. Type Gini Coefficient.
Once you have selected your parameters click Add.
Once you click Add on the input box, a map will appear automatically in your viewer which should look something like the map shown below. If you hover over any of the areas, the value for the attribute that you have mapped will show, as well as which group in the legend that specific area belongs to.
Hovering over a certain class within the legend will also bring up all of the areas that belong to that specific class (shown below, on a zoomed in version of the above).