Objective

This is an exploration of how polar charts (aka radar chart or spider diagram) can help visualize different characteristics of similar observations.

Data

This example will use the Colorado Fourteener dataset, which describes 58 mountain peaks in Colorado that rise above 14,000 ft (4,270 meters) in elevation.

The data includes variables that reflect hiker experiences climbing various peaks including,

The table below lists the first five peaks in the dataset including the relevant variables.

Mountain.Peak Mountain.Range Elevation_ft Standard.Route Distance_mi Elevation.Gain_ft Difficulty Traffic.Low Traffic.High
Mount Elbert Sawatch Range 14440 Northeast Ridge 9.50 4700 Class 1 20000 25000
Mount Massive Sawatch Range 14428 East Slopes 14.50 4500 Class 2 7000 10000
Mount Harvard Sawatch Range 14421 South Slopes 14.00 4600 Class 2 5000 7000
Blanca Peak Sangre de Cristo Range 14351 Northwest Ridge 17.00 6500 Hard Class 2 1000 3000
La Plata Peak Sawatch Range 14343 Northwest Ridge 9.25 4500 Class 2 5000 7000

Approach

Each mountain peak is ranked by each of the four key variables that reflect hiker experience. For example, the mountains can be sorted by the distance of the mountains standard route. From the shortest route to the longest. The rankings are then grouped into six bands. The peaks in band one have the shortest distance while the peaks in band six have the longest. The same is done for elevation gain, difficulty, and traffic.

The purpose of the bands is to provide a simple comparison of hiker experience characteristics between peaks. They also provide a common scale for variables of different measures.

The table below lists the first five peaks with the grouped ranking of hiker experience variables,

Mountain.Peak Mountain.Range Elevation_ft r_distance r_gain r_difficulty r_traffic
Mount Elbert Sawatch Range 14440 3 4 1 5
Mount Massive Sawatch Range 14428 5 4 2 3
Mount Harvard Sawatch Range 14421 4 4 2 3
Blanca Peak Sangre de Cristo Range 14351 6 6 3 1
La Plata Peak Sawatch Range 14343 3 4 2 3

The Chart

Here is a polar chart for Mount Elbert, the highest peak in Colorado. It shows the technical difficulty is low while the trail length and elevation gain is about average among other Colorado fourteeners. Possibly because the peak is accessible or perhaps because of its prominence, it is one of the most popular fourteeners.

Longs Peak is another prominent peak given its mark on the horizon West of the Front Range / Denver area. The chart shows that the trail distance, elevation gain, and difficulty are all higher for this peak than most other fourteeners. Nonetheless, Longs Peak is still a busy fourteener.

Capitol Peak is considered one of Colorado’s most difficult Fourteeners. That combined with its location near Aspen, CO positions this peak a long distance from Denver and other populated areas. The shape of this chart reflects the difficulty and relatively low traffic.

The End