Notes

• Input data is assumed to follow the geographic convention, where angles are measured in degrees and clockwise from north (i.e., the positive Y-axis).
• Colors were deliberately avoided to ensure the charts remain legible in printed (grayscale) form.
• The statistics in the Raw Data Plot are defined as:
  • md: mean direction (in degrees)
  • mrl: mean resultant length (range: 0 to 1)
  • csd: circular standard deviation (range: 0 to 2)
• In the Rose Diagram, the radius of each sector is proportional to the square root of the group's relative frequency. This means the area of each sector reflects the actual group frequency. In contrast, the Wind Rose diagrams use bar lengths and sectors that are directly proportional to the group's relative frequencies.
• The percentage of zero (0) speed values, representing calm conditions, is displayed in the charts. Calm conditions must be recorded as the numeric value 0. Do not use placeholder values such as -1, -999, or NaN. When speed is zero, the corresponding direction values have no physical meaning and are ignored in the analysis.
• While somewhat rudimentary, the Vector Stick plot can be made more readable by adjusting the vector length and separation parameters.
• The Unit Vector Path chart differs from the Progressive Vector Diagram in that it assumes all speeds have a magnitude of one. In other words, it represents direction only. In contrast, the Progressive Vector Diagram uses both the measured speed and direction. Because all vectors have equal length in the unit chart, it can provide a clearer view of the directional sequence without the influence of varying speeds.
• The Unit Vector Path, Vector Stick and Progressive Vector Diagram charts display the index (row number) of the data record next to the corresponding point. The numbering starts at zero.

Credits

Libraries and frameworks used in Directional Charts:

• Bootstrap 5 - CSS Framework

• Papa Parse - CSV data parsing

• Konva - canvas rendering and visualization

About

Directional Charts is a website dedicated to providing free and useful directional data visualizations. The site is developed and maintained by Skarn Consulting, a firm specializing in data analysis and geospatial technologies.

If you need custom data analysis, specialized charting, or help with technical data workflows, professional consulting services are available through Skarn Consulting.

Suggestions for improvements or bug reports are always welcome. Please feel free to email contact@skarnconsulting.com. If possible, include the dataset that caused the issue.

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