Web Plot Digitizer & Graph Data Extraction

What is Plot Digitization?

Plot digitization is the process of extracting numerical data from graph images, charts, and scientific plots.

Common Scenarios

Why Plot Digitization?

Problem:

You need data from a graph, but only have an image:

📊 Graph Image → ❓ → 📈 Numerical Data

📊 Graph Image → ❓ → 📈 Numerical Data

Solution:

Plot digitization tools reverse-engineer the graph to extract coordinates.

Types of Plots You Can Digitize

1. Line Charts

• Time series data
• Continuous functions
• Trends and forecasts

2. Scatter Plots

• XY data points
• Correlations
• Statistical distributions

3. Bar Charts

• Category comparisons
• Discrete values
• Histograms

4. Other Chart Types

• Pie charts (angles to percentages)
• Polar plots
• Ternary diagrams
• Map data (with projections)

How Plot Digitization Works

Step-by-step process:

1. Load Image

   • Upload or paste graph image

2. Set Coordinate System

   • Define X and Y axis ranges
   • Calibrate scale

3. Extract Data Points

   • Manually click points
   • Auto-detect (advanced tools)
   • Trace lines

4. Export Data

   • CSV, JSON, Excel
   • Copy to clipboard

Tools Available

No-Code Tools

Programmatic Tools

When to Use Plot Digitization

✅ Good use cases:

• Academic research (with proper citation)
• Personal analysis
• Data recovery from old sources
• When original data is unavailable

⚠️ Consider alternatives:

• Check if raw data is available in supplementary materials
• Email authors for original data
• Look for API or database sources
• Check data repositories (Figshare, Zenodo, Dryad)

❌ Don't use for:

• Bypassing paywalls to extract proprietary data
• Copyright infringement
• Misrepresenting data sources

Accuracy Considerations

Factors affecting accuracy:

Expected accuracy:

• High-quality digital images: ±1-2% error
• Scanned paper graphs: ±3-5% error
• Low-resolution screenshots: ±5-10% error

Legal & Ethical Considerations

Copyright:

• Graphs may be copyrighted
• Always cite original source
• Fair use may apply for research

Best practices:

• Acknowledge data source
• Note that data was digitized
• Compare with original when possible
• Don't redistribute as your own data