Maps
Categorical / unique-value map
Assigns geographic features distinct colours or symbols according to category.
- Map
- Geography
- Classification
What it answers
Where are different geographic categories located?
- Shape
- Features coloured by category
- What it shows
- Spatial distribution of classes.
Example
The question
Which sales team covers each region?
Regions by responsible sales team (categorical map)
Illustrative data. It belongs to no company.
When to use it
Use it when
Land use, administrative types or discrete classifications.
Avoid it when
Using a sequential palette that implies category order.
How to read it
Match feature colours or symbols with category labels.
Note
Use a categorical legend.
The data you need
- Layout
- Attribute table plus geographic boundaries
- Fields
- FeatureID: text; Category: text; geometry or geographic boundary reference
- One row is
- One geographic feature with a category. What is the grain?
- Rules
- Join category records to the matching features. Use consistent category labels and a categorical legend.
- Optional
- Names alone may be ambiguous. Geometry can be GeoJSON, a spatial file or a tool-supported boundary lookup.
- Preparation
- Validate the input grain and missing values. Join category records to the matching features. Use consistent category labels and a categorical legend.
- Units
- Categories have no numeric order or common denominator unless separately supplied.
Worked example
R1=Urban, R2=Rural. Assign distinct categorical fills; neither colour implies a larger amount.
| FeatureID | Category |
|---|---|
| R1 | Urban |
| R2 | Rural |