Urban thermal map design considerations: color, shading, and resolution

ABSTRACT

While satellite-based remote sensing techniques are often used for studying and visualizing the heat distribution in cities, they are limited in terms of spatial resolution, view bias, and revisit times. In comparison, modern Unmanned Aerial Vehicles (UAVs) equipped with infrared sensors allow very fine-scale (cm) data to be collected over smaller areas. We present a user study (n = 66) that outlines how satellite and drone-sourced thermal pseudo-color images compare in terms of map reading performance on three representative map reading tasks, how the choice of colormap affects map reading, and how a new shading augmentation to thermal maps based on high-resolution digital surface models can support interaction. Additionally, users provided explicit preferences indicating an inclination toward the shading augmentation, for the recently designed rainbow-style colormap turbo, and the cmocean thermal/FLIR ironbow colormap. However, we detail how user preferences and map reading performance are not always well aligned and are linked to issues of information content and visual clutter.

KEYWORDS:

• Colormaps
• perception study
• structure from motion
• thermal maps
• urban heat Island

Acknowledgments

The authors wish to thank Dr Stephanie Zick and Dr Santosh Rijal for their valuable comments and feedback during the project. The authors would also like to thank Max Dillon for his assistance during the UAV data collection.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data is not available.

Additional information

Funding

This research was supported by a grant from the Virginia Tech Institute for Society, Culture, and Environment.