5 ms·

This is cool but if we're not bound to static paper maps isn't the ultimate adaptive projection an interactive 3D perspective rendering of the globe? I suppose

This is cool but if we're not bound to static paper maps isn't the ultimate adaptive projection an interactive 3D perspective rendering of the globe? I suppose the downside is that you can't see both hemispheres at the same time. Then we can use our built-in spatial reasoning to compare how big some areas are by changing the perspective (as in real life), and shapes are only distorted by perspective which is very familiar.

mourner 5y ago
Yes, exactly! Globe view doesn't work when you want to show the whole world at once, which is useful for climate visualizations, political maps etc. Also, many organizations, especially governments and news media, often have their own requirements and conventions when publishing maps — some practical, some purely stylistic. For example, NY Times uses Albers USA for election maps (it has that iconic curved look of state boundaries), and National Geographic uses Winkel Tripel for their world maps.
zokier 5y ago
Ortographic projection is not really ultimate form for maps. Interactive (re)projection would definitely be nice but that applies to all projections equally, not just ortographic projection. But as the article notes, interactive reprojection is generally prohibitively expensive computationally.
- mourner 5y ago
  Globe view (orthographic projection) is coming to GL JS too![1] It had to be implemented differently (rendering to textures and then mapping them on a 3D mesh), but it should be quite fast. https://github.com/mapbox/mapbox-gl-js/issues/10784 https://github.com/mapbox/mapbox-gl-js/issues/10784
  - somishere 5y ago
    Amazing. Noted the draft PR and some mentions of a fall release .. are we talking imminent on a globe?
- wakeupcall 5y ago
  Before Google steamrolled the competition with free maps around 2010, streaming vectorial maps were quite a big thing in EU. I completely forgot the names of the big players in the area, however the maps were rendered on the client after being preprocessed (generally for streaming/rendering efficiency) via a flash or java applet. The maps were usually reprojected in variable UTM (according to your TZ - on the one I was working with) and/or using a Gauss projection, which is an extremely good compromise for whole countries. Because it was dynamic, the reprojection was a continuum while panning, usually imperceptible for the user at country scale. You could rotate the map, as well as query for road names in any spot instead of hunting down the (often missing) labels. I feel like the online services regressed quite a bit compared to that time, but maybe that's just me as I was working on the field. The mercator projection was mostly a fallback for worldwide maps, hardly used otherwise at smaller scales. When google maps started to provide worldwide free maps (which could be used as a 3rd-party service for free at the time), there was no way we could compete. OSM wasn't good enough yet, data licensing from international vendors was extremely high, and worldwide satellite imagery required an entire order of magnitude higher investment to compete. The companies I knew all pivoted to fleet management and similar services to survive.
  - jacobolus 5y ago
    > UTM and/or using a Gauss projection, which is an extremely good compromise for whole countries The transverse Mercator projection is an “extremely good” conformal projection for anything region located within a narrow band around a specified meridian. This describes some countries well (e.g. Chile, Finland, Vietnam, Portugal), but is rather terrible for anything stretched out East–West (e.g. Russia, Canada, Indonesia). Among conformal projections, for a compactly shaped country the stereographic projection is better. For a country lying along a parallel, a conformal conic projection is better. For a skinny country oriented at an arbitrary angle, an oblique Mercator projection is better. For small enough countries, any conformal projection works fine with low distortion.
    - wakeupcall 5y ago
      As I wrote, but to make it a little bit more explicit, the centerpoint moved as you panned. The vectorial stream was performed directly in WGS84. This allows to have of a country like Germany in view with very little distortion. As the zoom progressed outwards, it would morph to mercator. Nobody really noticed (sadly), and the choice of falling back to mercator was also due to it's popularity making it sort of "expected" more than anything else. The key point is that the reprojection was dynamic, and done on the client, optimized for the current viewing conditions. Stuff that today you can perform via JS without any problem if you forego the idea that maps need to be pre-rendered.
nielsbot 5y ago
I feel like this is what the latest Apple Maps update does? Even the "2D" maps are actually 3D when you zoom out.
bowmessage 5y ago
I wonder if one could use something like an antipode map to show two sides at once: https://engaging-data.com/antipodes-map/ https://engaging-data.com/antipodes-map/
mch82 5y ago
Cesium Sandcastle has a number of interesting 3D map examples, https://sandcastle.cesium.com/ https://sandcastle.cesium.com/. Best to use a desktop browser. Their mapping library is focused more on 3D.

mourner 5y ago

Yes, exactly! Globe view doesn't work when you want to show the whole world at once, which is useful for climate visualizations, political maps etc. Also, many organizations, especially governments and news media, often have their own requirements and conventions when publishing maps — some practical, some purely stylistic. For example, NY Times uses Albers USA for election maps (it has that iconic curved look of state boundaries), and National Geographic uses Winkel Tripel for their world maps.

zokier 5y ago

Ortographic projection is not really ultimate form for maps. Interactive (re)projection would definitely be nice but that applies to all projections equally, not just ortographic projection. But as the article notes, interactive reprojection is generally prohibitively expensive computationally.

mourner 5y ago
Globe view (orthographic projection) is coming to GL JS too![1] It had to be implemented differently (rendering to textures and then mapping them on a 3D mesh), but it should be quite fast. https://github.com/mapbox/mapbox-gl-js/issues/10784 https://github.com/mapbox/mapbox-gl-js/issues/10784
- somishere 5y ago
  Amazing. Noted the draft PR and some mentions of a fall release .. are we talking imminent on a globe?
wakeupcall 5y ago
Before Google steamrolled the competition with free maps around 2010, streaming vectorial maps were quite a big thing in EU. I completely forgot the names of the big players in the area, however the maps were rendered on the client after being preprocessed (generally for streaming/rendering efficiency) via a flash or java applet. The maps were usually reprojected in variable UTM (according to your TZ - on the one I was working with) and/or using a Gauss projection, which is an extremely good compromise for whole countries. Because it was dynamic, the reprojection was a continuum while panning, usually imperceptible for the user at country scale. You could rotate the map, as well as query for road names in any spot instead of hunting down the (often missing) labels. I feel like the online services regressed quite a bit compared to that time, but maybe that's just me as I was working on the field. The mercator projection was mostly a fallback for worldwide maps, hardly used otherwise at smaller scales. When google maps started to provide worldwide free maps (which could be used as a 3rd-party service for free at the time), there was no way we could compete. OSM wasn't good enough yet, data licensing from international vendors was extremely high, and worldwide satellite imagery required an entire order of magnitude higher investment to compete. The companies I knew all pivoted to fleet management and similar services to survive.
- jacobolus 5y ago
  > UTM and/or using a Gauss projection, which is an extremely good compromise for whole countries The transverse Mercator projection is an “extremely good” conformal projection for anything region located within a narrow band around a specified meridian. This describes some countries well (e.g. Chile, Finland, Vietnam, Portugal), but is rather terrible for anything stretched out East–West (e.g. Russia, Canada, Indonesia). Among conformal projections, for a compactly shaped country the stereographic projection is better. For a country lying along a parallel, a conformal conic projection is better. For a skinny country oriented at an arbitrary angle, an oblique Mercator projection is better. For small enough countries, any conformal projection works fine with low distortion.
  - wakeupcall 5y ago
    As I wrote, but to make it a little bit more explicit, the centerpoint moved as you panned. The vectorial stream was performed directly in WGS84. This allows to have of a country like Germany in view with very little distortion. As the zoom progressed outwards, it would morph to mercator. Nobody really noticed (sadly), and the choice of falling back to mercator was also due to it's popularity making it sort of "expected" more than anything else. The key point is that the reprojection was dynamic, and done on the client, optimized for the current viewing conditions. Stuff that today you can perform via JS without any problem if you forego the idea that maps need to be pre-rendered.

nielsbot 5y ago

I feel like this is what the latest Apple Maps update does? Even the "2D" maps are actually 3D when you zoom out.

bowmessage 5y ago

I wonder if one could use something like an antipode map to show two sides at once: https://engaging-data.com/antipodes-map/ https://engaging-data.com/antipodes-map/

mch82 5y ago

Cesium Sandcastle has a number of interesting 3D map examples, https://sandcastle.cesium.com/ https://sandcastle.cesium.com/. Best to use a desktop browser. Their mapping library is focused more on 3D.