"Globe Gores" explores the challenge of representing a spherical Earth on a flat map. The blog post focuses on globe gores, which are the individual, often lens-shaped, segments printed and then meticulously applied to a sphere to create a globe. It highlights the distortions inherent in flattening these gores for printing, referencing various historical gore patterns and explaining how their shapes attempt to minimize these distortions. The post showcases examples from the Library of Congress's collection, emphasizing the craftsmanship and precision required to create these essential components of historical globes.
Spacetime maps visualize travel time by distorting geographical maps. Instead of showing distances, these maps warp space so that the distance to any point represents the time it takes to travel there from a chosen origin. Faster travel methods result in less distortion, while slower methods exaggerate distances. The map demonstrates how travel time, rather than physical distance, shapes our perception and accessibility of different locations. It allows users to select various transportation modes (car, walking, public transit) and adjust the starting point to explore how travel time changes the perceived world.
HN users generally praised the map's concept and execution. Several appreciated its ability to visualize travel time in a novel way, highlighting the dominance of air travel over geographical distance in modern times. Some pointed out interesting details revealed by the map, such as the relative isolation of Australia and New Zealand. A few users suggested potential improvements, like the inclusion of high-speed rail lines, ferry routes, and more granular city-level data. There was also discussion of the projection used and its potential distortion effects. Finally, some comments offered alternative methods for visualizing similar data, referencing existing tools or suggesting different approaches.
The blog post explores whether the names of lakes accurately reflect their physical properties, specifically color. The author analyzes a dataset of lake names and satellite imagery, using natural language processing to categorize names based on color terms (like "blue," "green," or "red") and image processing to determine the actual water color. Ultimately, the analysis reveals a statistically significant correlation: lakes with names suggesting a particular color are, on average, more likely to exhibit that color than lakes with unrelated names. This suggests a degree of folk wisdom embedded in place names, reflecting long-term observations of environmental features.
Hacker News users discussed the methodology and potential biases in the original article's analysis of lake color and names. Several commenters pointed out the limitations of using Google Maps data, noting that the perceived color can be influenced by factors like time of day, cloud cover, and algae blooms. Others questioned the reliability of using lake names as a proxy for actual color, suggesting that names can be historical, metaphorical, or even misleading. Some users proposed alternative approaches, like using satellite imagery for color analysis and incorporating local knowledge for name interpretation. The discussion also touched upon the influence of language and cultural perceptions on color naming conventions, with some users offering examples of lakes whose names don't accurately reflect their visual appearance. Finally, a few commenters appreciated the article as a starting point for further investigation, acknowledging its limitations while finding the topic intriguing.
Mercator: Extreme pushes the boundaries of the web Mercator projection by visualizing the entire world map at incredibly high zoom levels, far beyond traditional map applications. It demonstrates the inherent distortion of Mercator as landmasses become increasingly stretched and warped, especially near the poles. The project uses custom tiling and rendering techniques to handle the immense detail required for such extreme zoom levels and allows users to interactively explore this unusual cartographic perspective.
Hacker News users discuss the extreme Mercator projection, mostly focusing on its comedic distortion of landmasses at higher latitudes. Some commenters appreciate the project as a clear demonstration of how Mercator's cylindrical projection stretches areas away from the equator. Others highlight the educational value, contrasting it with the common misconception of Greenland's size relative to Africa. A few users suggest alternative visualizations, such as a globe or comparing the distorted areas to their true size on a map using different projections. One commenter notes the inherent difficulty in accurately representing a sphere on a flat surface, while another points out the project creator's other interesting work. There's also brief discussion of the historical context and usage of Mercator projections, including its suitability for navigation.
Esri has released the USA Hydro Network v1.0, the most detailed open map of US surface water ever created. Derived from the 3D Elevation Program's 1-meter resolution data, this hydro network boasts unparalleled accuracy and granularity, providing a much clearer picture of water flow compared to previous datasets. It features over 100 million flowline segments and includes detailed information on flow direction, stream order, and watershed boundaries, offering valuable insights for applications like hydrologic modeling, environmental management, and infrastructure planning. The data is freely available for download and use.
HN commenters generally expressed enthusiasm for the detailed water map, praising its visual appeal and potential uses for conservation, research, and recreation. Some raised concerns about the map's accuracy, particularly regarding ephemeral streams and the potential impact on regulatory determinations. A few commenters discussed the underlying data sources and technical aspects of the map's creation, including its resolution and the challenges of mapping dynamic water systems. Others shared links to related resources like the National Hydrography Dataset (NHD) and other mapping tools, comparing and contrasting them to the featured map. Several commenters also highlighted the importance of accurate water data for addressing various environmental challenges.
Summary of Comments ( 1 )
https://news.ycombinator.com/item?id=43546607
HN users discuss the practical aspects of creating globes from gores, touching on the distortions inherent in representing a 3D sphere on a 2D surface. Some commenters delve into the history of globe-making and the different projections used, while others suggest software and techniques for generating gore patterns, including open-source options like QGIS and G.Projector. A few express fascination with the intricate geometry involved, and some share personal anecdotes about building their own globes. The challenges of aligning and assembling the gores are also highlighted, with tips offered for achieving a smooth, accurate final product. Several users appreciate the Library of Congress's detailed blog post, finding it informative and inspiring.
The Hacker News post "Globe Gores" (https://news.ycombinator.com/item?id=43546607) linking to a Library of Congress blog post about globe gores has a modest number of comments, offering a few different perspectives on the topic.
Several comments focus on the practical aspects of globe construction. One user highlights the ingenuity of the gore design, allowing a flat map to be transformed into a three-dimensional sphere. Another points out the inherent distortions involved in representing a spherical surface on a flat plane, referencing the Mercator projection as a common example and mentioning how gores offer a different approach to this problem. A further comment elaborates on the challenges of creating distortion-free maps, mentioning the impossibility of perfectly representing the Earth's surface on a flat medium and linking this to the mathematics of manifolds.
Another commenter discusses the historical context of globe making, referencing the long history of this craft and its significance in navigation and exploration. They specifically note how the creation of accurate globes was a challenging technical feat in earlier eras.
One comment thread delves into the specific geometry of globe gores, discussing the calculations and considerations involved in designing them. One user questions the specific number of gores used in the example and initiates a discussion about the tradeoffs between the number of gores and the resulting distortion. Another user provides mathematical insights into these tradeoffs.
A few comments express general appreciation for the elegance and ingenuity of globe gores. One simply expresses delight at learning about this topic, while another appreciates the visual appeal of the gores themselves.
Finally, one comment pivots the discussion to digital globes, comparing and contrasting traditional globe-making techniques with modern digital representations of the Earth. They mention the prevalence of digital globes and the potential for interactive exploration offered by these tools.