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Related Experiment Video

Updated: May 29, 2026

Applying Hyperspectral Reflectance Imaging to Investigate the Palettes and the Techniques of Painters

Applying Hyperspectral Reflectance Imaging to Investigate the Palettes and the Techniques of Painters

Published on: June 18, 2021

Value-by-alpha maps: An alternative technique to the cartogram.

Robert E Roth¹, Andrew W Woodruff, Zachary F Johnson

¹GeoVISTA Center, Penn State University, 302 Walker Building, University Park, PA 16802.

The Cartographic Journal

|September 20, 2011

Summary

This summary is machine-generated.

Value-by-area maps (cartograms) distort geography to represent data. A new value-by-alpha map method avoids this distortion by adjusting transparency, preserving map shape and topology for better data visualization.

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Facilitating the Analysis of Immunological Data with Visual Analytic Techniques

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Published on: January 2, 2011

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Facilitating the Analysis of Immunological Data with Visual Analytic Techniques

Facilitating the Analysis of Immunological Data with Visual Analytic Techniques

Published on: January 2, 2011

Area of Science:

Cartography
Geographic Information Systems (GIS)
Data Visualization

Background:

Cartograms, or value-by-area maps, are widely used for social data representation.
These maps adjust enumeration unit size based on a variable, but distort geographic shape and topology.
This distortion compromises map-reading effectiveness for elemental and general tasks.

Purpose of the Study:

Introduce a novel cartographic technique: the value-by-alpha map.
To overcome the shape and topology compromises inherent in traditional cartograms.
To enhance data visualization by preserving geographic integrity.

Main Methods:

Developed a value-by-alpha map representation.
This method adjusts the alpha channel (transparency) of map units, not their size.
Enumeration units are visually equalized based on a secondary variable via transparency.

Main Results:

The value-by-alpha map successfully equalizes the basemap visually.
This technique preserves the original shape and topology of the geography.
It offers an alternative to size-adjusted cartograms, mitigating distortion.

Conclusions:

Value-by-alpha maps provide a viable alternative to traditional cartograms.
This method enhances data visualization by maintaining geographic accuracy.
It offers improved effectiveness for map-reading tasks without compromising spatial integrity.