Compare and rank
Parallel coordinates plot
Draws each observation across an axis for every variable.
- Plot
- Multivariate comparison
- Relationship
What it answers
How do many numeric profiles differ?
- Shape
- Polylines across parallel axes
- What it shows
- Clusters, trade-offs and unusual profiles.
Example
The question
Which products stand out across price, margin, sales and returns?
Eight products across four measures (parallel coordinates)
Illustrative data. It belongs to no company.
When to use it
Use it when
Exploring multivariate profiles with comparable scaling.
Avoid it when
Many overlapping lines without highlighting or incompatible scales.
How to read it
Follow an observation across axes and compare bundles or crossings.
Note
Axis order and normalisation affect patterns.
The data you need
- Layout
- Wide observation table
- Fields
- ObservationID: text; V1...Vp: numeric columns
- One row is
- One observation with several measured numeric variables. What is the grain?
- Rules
- Align variables by observation. Decide scaling, missing-data handling and which columns are features.
- Optional
- Optional Group. PCA, clustering and correlations require calculations before rendering their derived results.
- Preparation
- Align measurements by observation ID, select relevant variables and handle missingness. Scale or standardise only where the analytical method requires it.
- Units
- State the unit of every coordinate/variable. A unitless transformed or standardised scale must be identified; no common denominator is assumed.
Worked example
Normalised profileA=(0.2,0.8,0.4), B=(0.7,0.3,0.6). Lines cross between first two axes, indicating opposing profiles.
| ID | V1 | V2 | V3 |
|---|---|---|---|
| A | 10 | 30 | 5 |
| B | 12 | 20 | 8 |
| C | 18 | 25 | 6 |
