[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)