Cartographica has some powerful tools for creating and manipulating styles and for applying color palettes to a set of styles. This tip is about using these functions to create a smooth ramp across a range of values, without having to determine exactly how many steps to add. This is intended for use with relatively small (<256 feature) lists, such as provinces or counties, and values that are unlikely to be repeated, such as population or area.
- Double-click on your layer to open the Styles window
- Make sure you have a column selected in Based On
- Choose Distribute Unique Values from the gear menu
This will create a single sub-style for each individual value in the list. We won't be directly using these, this is just to approximate the number of styles we need to represent the data well.
- Choose Distribute Equal Intervals from the gear menu
This will redistribute across the entire range based on an equal number of weightings from lowest to highest.
- Choose Window > Show Color Palettes to display the color options
- Drag a suitable color palette from the Color Palettes window to your style list
This creates a relatively good ramp without having to manually create every entry. If you have a much larger set of values, it is better to manually create the number of styles you need to step the value correctly and then follow steps 4-6.