# Spiral Strip
## 1 Introduction  
In the field of climate change, there is a great need to provide effective visual material that shows the changes in the environment that are already happening or will be happening, which would be easy to grasp and intuitively understood by the majority of the general public. One excellent example of such material is the warming stripes infographic (sometimes also referred to as climate stripes, climate timelines, or stripe graphics) designed and published by University of Reading climate scientist [PERSON] in 2019 [1]. The warming stripe features a very minimalistic rectangular design consisting of narrow color-coded vertical segments (stripes) arranged horizontally from left to right showing a temporal sequence of temperatures. The colder temperatures are represented by blue shades, while red shades represent warmer temperatures. This typically results in a nonmonotonic color transition from blue to red, clearly showing the warming trend of Earth's climate and the inherent variability of the climate system. The meaning of the graphic is very easy to grasp and can be intuitively understood by a casual observer. The author later created a website, showyourstipes.info (accessed on 1 May 2022) where stripe images can be generated for many regions around the globe. The images have been downloaded more than a million times, have been widely shared online, and are used to decorate ties, cufflinks, and cars [1]. Here, we present a new type of visual graphic we call a Spiral Strip. Its design is loosely based on the warming stripe, but instead of a horizontal geometry, the color-coded segments are arranged in an Archimedean spiral [2]. With spiral geometry, the length of individual segment can be larger compared to the warming stripe, facilitating displaying a longer series, and providing more textual and numerical information along each segment. The new graphic is more square, whereas the warming stripe typically has a larger horizontal dimension than the vertical. The spiral can also start some way off the center, leaving the central region empty, so a title or supporting text can be added in the middle. The width and length of each segment can be different, which can be used to convey additional information (in addition to the one shown by the color-coding). There have been multiple previous attempts to use spiral geometry to visualize data. One of the earliest examples can be found in [3], where a line-type graph in spiral geometry was used to visualize a time series data. The authors in [4] used a 3D spiral for calendar visualization, while in [5], the authors tried various approaches with spiral visualization, including displaying data in various forms in 3D. In [6] the authors tested various spiral-geometry-based approaches to visualize time series data, with a special focus on enhancing the identification of periodic patterns. They tested various approaches, such as changing the visual appearance of the spiral, drawing multiple spirals, and displaying them all together or sequentially in animation, using interaction techniques, or displaying it in 3D as a helix. The authors in [7] presented a tool for fixed-width spiral track visualization based on a two-tone pseudocoloring approach. Quite recently, the authors in [8] presented a spiral visualization tool called spiralize, which is available as a R package. The tool supports the visualization of multiple fixed-width tracks running along the spiral, where each track serves as an independent plotting region, thereby allowing for building very complex graphics. Our focus was the development of a graphic that would not be too complex and could thus be intuitively understood by a casual observer. Our aim was also to publish a freely available Python software package that would be easy to use by the users to draw their own spiral strip images. While some other tools, such as the spiralize package, already exist, they do not offer the complete set of functionalities we were trying to implement.