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Maps have been around for thousands of years and have been widely accepted as the means of representing spatial information. We all know about several map projections,each with their merits and demerits.

However, I often wonder, with all the progress GIS has made, why not make good 3-d globes as the basis of GIS Systems. Most of the outputs of GIS are intended to be presented digitally and not printed. Having near accuarate representation of the curved earth will solve many problems regarding choosing the correct projection.

Is ArcGlobe and GoogleEarth (and the likes) the way forward to represent and analyse information upon? What do you think?

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Could you explain what you mean by a "good 3-d globe," the sense in which one would serve as the "basis" of a GIS, and exactly how this differs from what most GISes already can do? –  whuber Apr 9 '13 at 5:30
    
I mean that instead of using map projections, why not use globes that do not require a projection. I am aware that the shape of earth can not be represented perfectly even with a globe. But at least the problems associated with projecting a spherical surface on a plain will be mitigated somewhat. It is just an idea I was pondering about. Wanted to know its ramifications. –  Dipto Apr 9 '13 at 5:50
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GISes already do this, using spherical ("geographic") coordinates and are capable of sub-millimeter accuracy. But to avoid using a map projection for cartography, one would have to have an ellipsoidal output device. I remain puzzled about the thrust of your question and what you're really looking for. Related questions can be found at gis.stackexchange.com/questions/53728, gis.stackexchange.com/questions/16251, and gis.stackexchange.com/questions/23660. –  whuber Apr 9 '13 at 6:03
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Reading your question makes me think that you are only looking at GIS as an avenue for Cartography. While Cartography is an element of GIS, it is not the sole part of GIS. The power and use of GIS comes from the analysis. The majority and typical analysis conducted by GIS'ers does not require the third dimension. Furthermore, being forced into a geographic projection would eliminate many of the powerful analysis tools available for GIS analysis. –  Ryan Garnett Apr 9 '13 at 7:50
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To me that would not be possible with all the algorithms, as they require local projected units. Take a buffer for example. Very simple analysis, but if it were in a geographic projection the user defined "buffer distance" would be interpreted as degrees. You could do this by doing a on the fly conversion, but that would be a bit more taxing in the computing. Global mercator projections allow for using metres as units of measure, but the issue of accuracy and precision comes into question. –  Ryan Garnett Apr 9 '13 at 17:40

3 Answers 3

3D globes and the like are very useful for visualization purposes. You can instantly see Global Level and Continental Level data, and spatial relationships and distances are easily understood.

However you don't really need a Globe for that. As SS_Rebelious has mentioned, a Globe on a Flat Screen, is basically an Azimuth Projection. For example, Just look at the Maps on this page, which show the distance from North Korea.

You cannot do this on a Static Globe. The Globe will have to be manipulated and you will have to Navigate around to get the complete Picture.

And when you zoom down to say City Level, How much of the spherical nature of the Globe are you truly using? At that level, the local terrain is much more important in visualization than the spherical nature of the earth.

Further more, can you really do with a spherical model? What about high precision geoids and local datums? How are you going to handle them?

We use 2D Maps because they work, if used properly. They have the following advantages over digital Globes:

  • It is possible to see the entire earth at once. Great Example: enter image description here

  • When used with an appropriate projection, you can show and highlight special aspects of Geography.

  • Attribute based Rendering can be done in a simple way. For example, on a 2D map, you can clearly see that a particular region is colored a particular color. Most digital globes add a virtual atmosphere, often you cannot make out colors near the boundary of the visible earth.

A Digital Globe is perfect when You need to fly and revolve around it. For pretty much any other use, wonderful projections have been developed which are far better.

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so we could have a webmapping app which changes projection depending on zoom level ,or on some functions like measuring distance, or finally on the perception of the user ? if yes i would like to know some examples of this trick. –  geogeek Apr 10 '13 at 11:53
    
@geogeek I am not sure what you want to see, but have a look at this: jasondavies.com/maps/transition –  Devdatta Tengshe Apr 10 '13 at 13:24
    
Great Example , thanks a lot :D –  geogeek Apr 10 '13 at 14:02

This is not the first time I encounter such question and generally it is asked by people outside of geospatial industry that are not familiar with cartographic theory or with practice needs (this is just my observation).

As to the question:

  1. A "3d Globe" that you see on the screen is nothing less than just an Azimutal projection... And there is no such projection that satisfy all the needs... Think about it.
  2. So still if you insist on a "3d Globe" representation then how would you see the whole world at the same time? Don't you need a projection for that (example)?

Finally, try to work with the real project. If the "3d globe" (and there are plenty of app to help you with that) representation will satisfy all your needs - lucky you.

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How about google earth? or does a flat screen negate your posit. You can walk out your door and then you have the most fully featured but non abstracted 3D globe imaginable.

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