The colors that are shown on the spatial map are determined by a two-step process:
You indicate in the UI what value should be used to determine the color
Color by Number of assets or Number of records: the visual analytics page will count the number of records or assets, and use that numeric value to determine a color
Color by Occurrence: use a boolean value to determine whether the pixel should be colored. All pixels that are colored will use the same color.
Color by Attribute value: select the value of an attribute or property in your data, and use that value to determine the color
Map the value to a color:
When the value is numeric, this is done through a color map.
This color map can for example specify that all values between 3 and 5 should be red, values between 5 and 7 blue, … .
When the value is an enum or string, you also use a color map but one that maps strings onto colors (which we call a color palette).
The color palette can for example map "Fishing vessel" to green and "Oil tanker" to red
When the value is a boolean, it is mapped onto a fixed color.
All the numeric color maps allow to:
Define a color map for a specific range
Define a fixed color to use when the value falls outside that range
Define a color to use when there is no value available for the chosen property.
For example when styling your data according to a speed property:
You can specify a color mapping for the speeds between 0 and 100 km/h
Specify a color for all speeds < 0 km/h
Specify another color for all speeds > 100 km/h
Specify the color to use when there is no speed information available
The following options are available for the color maps:
Interval based color maps
Gradient color maps
Additive color maps
In an interval based color map, you specify numeric intervals and the corresponding color.
An example use-case for this type of color map is visualizing the speed of cars. Cars travelling on public roads have to adhere to the speed limits. For example in Belgium the speed limit for the majority of the roads is either 30, 50, 70, 90 or 120 km/h.
In this example, you could use the following intervals in your color map:
When using such a color map and looking at an area where cars are only allowed to drive 50 km/h, you will easily spot the ones breaching the speed limit.
In a gradient color map, you select the start and end color, and all other colors in the range will automatically get derived by interpolating between those 2 colors.
An example use-case for this is if you are not interested in the exact value, but rather want to get a feeling for where the low and high values are.
Very similar to a gradient color map, but instead of selecting a start and end color you only select the start color. That start color is then added up until reaching white.
These are some very specific color mappings that are well-known and widely used in visualization software.
Examples are the Jet and Hot color maps.
In a color palette, you define a mapping from a string value to a color.
When the value equals Oil Tanker, use green
When the value equals Fishing Vessel, use pink
For the string values that are not present in the mapping, you have the option to:
Use a fixed color
Use a random color
Color them transparent
You can also select the color in case there is no value for the property available.