[HN Gopher] Oilslick - an elevation map showing fine detail in t... ___________________________________________________________________ Oilslick - an elevation map showing fine detail in terrain Author : mleonhard Score : 94 points Date : 2022-02-19 19:06 UTC (3 hours ago) (HTM) web link (mrgris.com) (TXT) w3m dump (mrgris.com) | pmichaud wrote: | This is awesome! I've spent a lot of time thinking about similar | issues and making do with 16bit grayscale, but reading | interactive maps or tiles from apis, I've seen all the problems | mentioned in the intro, and it only took me a couple minutes to | get the hang of reading the weird light bands. I don't know if | it'll catch on, but I think it's a really cool effort! | clairity wrote: | the potential effects of rising water levels are pretty clearly | outlined in coastal areas like california. most of silicon | valley, as well as LA, would be underwater and the central valley | would become a large inland sea. | tomjakubowski wrote: | No. Most of LA is shielded by bluffs and coastal hills and | mountains. Even at 10 feet of sea level rise, within LA County | only Long Beach and areas of Venice near the marina would | really be affected. Some beachfront property in the South Bay, | too. | | https://coast.noaa.gov/slr/#/layer/slr/10/-13087637.78362574... | clairity wrote: | no, it's not. LA is a river basin historically, and even with | some bluffs, it's not protected enough from ingress all | around (and water falls from the sky too!). | | the simulator you linked to makes no sense (or maybe it's | broken in my ad-blocking browser). it shows ingress on palos | verdes, which is basically a mini-mountain right on the shore | that would become an island with enough sea rise. | HPsquared wrote: | This is in general a really nice way to visualise datasets which | have both a wide range of values, and "relative" local variations | that comprise a small fraction of the overall range. | webstrand wrote: | I wish the map had some kind of reference key, or the ability to | query for height at any given point. It seems like the color- | scheme breaks down on very steep slopes, like those of the Andes | in Chile. | | I also wonder if Greenland is actually that smooth, or if the | elevation sample rate is just much lower for inland Greenland. | martyvis wrote: | The key is at the right of the map. | lazide wrote: | Isn't inland Greenland mostly ice? | hyperpape wrote: | This seems effective at showing how nearby areas relate to each | other (or at least where ridges and changes are) and hopeless at | global comparisons. After staring at it for a little while, I | have no intuitive sense of what any area's height is, unless it's | the orangey/black colors that appear near sea-level, or the | bluish color that appears in the himalayas. | [deleted] | [deleted] | tombh wrote: | I can clearly see the ancient geological strata of Carboniferous | and Devonian rock layers in my home country of Wales, | particularly Pembrokeshire and the Gower! So my layman theory | would be that tectonics pushed these once horizontal layers | nearer to the vertical, and that weathering processes eroded them | slightly differently, giving each layer slight height differences | that are imperceptible on most terrain colourshcemes, but | Oilslick happily highlights. Hats off | clusterfish wrote: | Interesting idea, but elevations lower than 50m or so are colored | black as if they're water. Looks like an apocalyptic flood. Don't | understand why the author didn't make sea level a clearly visible | threshold. | sebow wrote: | I somewhat like the map precisely because of this fact.Waters | and oceans are not at the end of the day solid, however vast | they might be(however this is not to say this map is fully | about elevation, because underwater elevation is mostly missing | if not existent).Though it might look unnecessarily | apocalyptic, it's somewhat a good reference of how the tectonic | plates, the planet, and everything else in nature evolves.I'm | personally fascinated for example by the both 'negative' | (rivers) and 'positive' (hills, pre-mountain areas) that form | tree-like structures.If we used traditional elevation map such | quirks would be less noticeable, at least in my opinion | clusterfish wrote: | It's just a strange choice given that the author is lamenting | about how traditional relief maps don't represent both | coastlines and high mountain terrain well... And then | proceeds to not represent coastlines well, even though that | would definitely be possible with their approach. | FpUser wrote: | This looks like a piece of art. Very nice. | deschutes wrote: | It doesn't do a very good job of delineating the coast. Seems | like +- 50 ft is black. Puget sound is unrecognizable on my | display. | genericone wrote: | Looks like you want a section view type feature, automatically | at sea level. I think that would be useful if the color delta | is right. | rendall wrote: | > _This creates a zig-zagging pattern of the lightness level. | Each cycle, or zig+zag from black - white - black again, covers | 500m of elevation._ | | I find this zig-zagging of lightness level very difficult to | interpret. Greenland looks to me like a series of concentric | hills. Perhaps if I were to get used to it, it would become | easier to understand. | | But the monochrome areas are really neat to see, and it's very | easy to understand what's happening geologically in, say, | Finland. | | A feature I would like to see is a shareable URL for regions. | | Northern Scandinavia looks positively Lovecraftian. | twofornone wrote: | >Greenland looks to me like a series of concentric hills. | | What you are looking at is an implicit contour map - normally | these lines are drawn in post processing to highlight levels of | constant elevation. If you follow the "concentric hills" you | are staying level and going around the hill. If you move | perpendicular to them you are going straight up the slope in | the direction of the gradient. | SECProto wrote: | The is one of the coolest maps I've seen. I thought that showing | strong contrast on minor elevation changes would hide | information, but it does the opposite. Great resource and great | summary on the left tab thing | pbowyer wrote: | This makes seeing the rivers and catchment areas easier than | other maps I'm used to. | | It also easily highlights features that the sea has cut away in | the past. For example if you search "Isle of Wight" and scroll | west, you can see the ridge that runs W-E across the Isle of | Wight continuing on the Isle of Purbeck to the west. I knew that | a long time ago it was all joined up as land, but this map shows | this particular feature more clearly than a geology map. | usrusr wrote: | That's a nice experiment, take something a mundane as contour | lines, turn it to eleven and see where it gets you. | | Is it a materialized remapping of the underlying .hgt or is it | done client-side, in some webGL-shader? (if we'd even need that, | plain js or wasm might be good enough these days?) I could | imagine this being even more compelling if we could interactively | shift the remapping to put regions we are currently interested in | into high saturation parts (and/or scaling it down to make | mountain ranges "readable"). | | Another, even simpler reading help would be sampling the color at | the mouse position and displaying a translation into meters. | | In any case, the vertical perception amplification (compared to | other visualisations) is truly awesome! in my region I can easily | make out the forest offsets that SRTM and LIDAR data happens to | come with, and bigger roads cutting through those forests. | trs8080 wrote: | I think there's a misunderstanding of the data here. It appears | that the underlying data used for this map is DEM data | (https://en.wikipedia.org/wiki/Digital_elevation_model), which | encodes values in the red, green, and blue channels of an image | representation of a geographic area. You're not supposed to | visualize this data directly -- instead, you combine those values | in a simple formula to obtain a height value, then you use _that | value_ to create visual maps. This map just restyles what is | geographically analogous to the binary representation of "hello, | world" instead of the output itself. | | You can search google for "terrain map" or "elevation map" and | find many beautiful examples of accurate elevation data. | | Edit: This is a good tutorial on how to derive the correct | values: https://github.com/syncpoint/terrain-rgb | sahkopoyta wrote: | >You're not supposed to visualize this data directly -- | instead, you combine those values in a simple formula to obtain | a height value, then you use that value to create visual maps. | | Isn't this exactly what has been done here? You can even see | the legend at the right side of the screen. | trs8080 wrote: | This still shows the uncombined components. What does the | color blue represent in this map? Is it a height? -500m? | 5000m? 6000m? What does white represent? This map is a | fundamental misrepresentation of the underlying data. | | This is the formula: | | height = -10000 + ((R * 256 * 256 + G * 256 + B) * 0.1) | lolc wrote: | Wow! I went looking at my region and it was so easy to see the | river valleys and plains. Before, I only had a rational | understanding how downstream will always be lower. This is the | first time I intuitively saw where water flows on a map! | samwillis wrote: | If you didn't see it a few weeks ago this was submitted to HN: | | https://river-runner-global.samlearner.com/ | | "Drop a raindrop anywhere in the world and watch where it ends | up" | | https://news.ycombinator.com/item?id=29841737 | | Super fun! | zestyping wrote: | I get that this is something I need to learn to read, and that | there is the potential for it to be extremely useful once I have | learned how to read it. | | It's hard to learn, though, without quick feedback on whether I'm | reading it correctly. It would be a big help to show the | elevation wherever I'm pointing -- either with a miniature scale | or a number or both -- so I can get direct feedback on whether | it's increasing or decreasing and by how much, and to help me | recognize the sequence of hues. | | I'm also really curious to see what this looks like if the | lightness is always increasing, with a sawtooth discontinuity | where it wraps around after hitting 100%. Yes, this would produce | really hard edges in arbitrary places, but that might be worth it | in exchange for the hugely helpful certainty of always knowing | which way is up. | Freak_NL wrote: | Being Dutch living in one of those barely visible dark blue | stretches of below sea level literal low-lands makes one rather | aware of our precarious national position as far as rising sea | levels are concerned. | Gibbon1 wrote: | I read something that said you guys are sort of in luck as long | as Antarctica doesn't go. Apparently the gravitational forces | from ice in Greenland pull the ocean higher. So as the ice | melts the ocean around Greenland will fall while farther away | it will rise. There is a zone around Greenland where it's a | wash. And the Netherlands is in it. | | The east coast of the US, Florida, and the Gulf coast are | totally hosed though. | TT-392 wrote: | We have all the knowledge, and even a special government branch | in place here to fight the sea, I am sure we'll be fine | TaylorAlexander wrote: | > a special government branch in place here to fight the sea | | Ah that ought to do it. | eCa wrote: | Unless you're being facetious, you might want to read up on | things like the Delta Works[1], the Zuidersee Works[2] or | the smaller project of Maeslantkering[3]. | | If there's one country that has had long experience in | dealing with the threat from the oceans, it's the | Netherlands. And these kinds of projects don't really lend | themselves to organizations that require profit for their | investments. | | (I'm not dutch, but I have biked across the 32 km long | causeway of Afsluitdijk[4] and parts of the Delta Works.) | | [1] https://en.wikipedia.org/wiki/Delta_Works | | [2] https://en.wikipedia.org/wiki/Zuiderzee_Works | | [3] https://en.wikipedia.org/wiki/Maeslantkering | | [4] https://en.wikipedia.org/wiki/Afsluitdijk | whoisburbansky wrote: | I mean it's been working pretty well so far, it would seem. | TT-392 wrote: | Or, fine, may not be the right word, more like, a lot better | off than a lot of other countries. ___________________________________________________________________ (page generated 2022-02-19 23:00 UTC)