# Spiral Strip
## 3 Results  
Here, we show some examples of the new graphic. All the examples were drawn using the Spiral Strip Python package described in Section 2.2. The source code and the data for all examples are available in the package. Figure 2 shows the first four examples that are based on the temperature data from Ljubljana, Slovenia. They all show a hundred-year sequence of average yearly 2-m temperatures in Ljubljana in the period of 1917-2017. The yearly averages were calculated from the monthly average temperature data in the same period, which the Slovenian Environment Agency kindly provided. Figure 2a shows a rather thin spiral strip that makes approximately five and a half loops around the center from start to finish. The most recent year in the dataset (2017) is positioned at the start of the spiral near the center, while the first year (1917) is positioned at the other end of spiral. The spiral strip was drawn using the following parameter values: \(r_{0}=10\), \(\varphi_{0}=45^{\circ}\), \(w=20\), \(l=40\) and \(s=15\). Matplotlib's _coolwarm_ color map, which includes a transition from blue to red, was used to define the segment colors. Similar to the warming stripes, the colder years are thus represented in more bluish colors and the warmer in more reddish. The coldest year was 1940, when the average temperature was only 8.4 \({}^{\circ}\)C, and the warmest year was 2014, with a temperature of 12.6 \({}^{\circ}\)C. Like the warming stripes, there is a color transition from the bluish colors at the outskirts of the spiral toward more reddish colors near the center, thus clearly showing the warming trend of Earth's climate and the inherent variability of the climate system. As long as the observer knows that the colors reflect the temperatures, and that the time increases towards the middle, the meaning of the graphic is very easy to grasp and can be intuitively understood. Figure 2b is identical to Figure 2a, with the exception that labels were added near each segment indicating the year. The orientation of the text is along vector \(\mathbf{e}_{l}\). In order to keep the spiral strip the main focus of the graphic, the label font size is small, and the colors of the labels are identical to the colors of the corresponding polygons. An alternative option could be to display the yearly temperature values instead of the years, display both, or intermittently display the year and the temperature. Figure 2c shows a strip with wider and shorter segments. Compared to the strips shown in Figure 2a, the segment width was increased from \(w=20\) to \(30\) and the length reduced from \(l=40\) to \(10\), with the rest of the parameters being the same. Due to the shorter segments, the spiral strip makes only two full loops around the center from start to finish. Similar to Figure 2b, the labels show the years in small font and are color-coded identically to the polygons in order for the spiral strip to remain the main focus of the graphic. Figure 2d is similar to Figure 2a, but with the spiral strip starting some way off the center. The only parameter that changed compared to Figure 2a is \(r_{0}\), which was increased from 10 to 120. Since the spiral does not start near the center, the middle region is empty, allowing for adding a title. The title _Ljubljana temperature_ was manually added to the image after it had been produced. The title clarifies for the casual observer what is shown on the graphic. The last two examples are not related to climate. Figure 3 shows the increase in global population in the period of 1900-2021, with each segment representing one year. The image is based on the freely available population data published at ourworldindata.org ([[https://ourworldindata.org/world-population-growth](https://ourworldindata.org/world-population-growth)]([https://ourworldindata.org/world-population-growth](https://ourworldindata.org/world-population-growth)) (access  
Figure 2: Four spiral strips all showing a hundred years of average yearly 2-m temperatures in Ljubljana in the period of 1917–2017.