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What is required to write a Google Earth-like application?

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loaded:
Hi All,
Firstly ;
Has anyone worked on this at any level before?
If yes, what kind of difficulties were encountered on this path?
If not, have you come across any other work?
Or ;
Is it possible to write an application similar to Google Earth (in terms of Visuals and Performance) with existing packages of Lazarus or packages from OPM?
If possible, what are the necessary topics for this?
Which platforms should be researched in order to learn these subjects from novice to master?
I would be glad if you share your knowledge and experience. Respects.

MarkMLl:
https://wiki.lazarus.freepascal.org/LazMapViewer

Apart from that, what's needed is a massive amount of input data and an excellent understanding of spherical geometry as applied to the geoid. QGIS already handles both of these.

As a general point, remember that Google Earth already has a great deal of stuff accessible: ability to load overlay images, ability to do a timed reload (which I've never got QGIS to do reliably) and so on.

MarkMLl

loaded:
First of all, thank you very much for your reply and information MarkMLl

--- Quote from: MarkMLl on November 08, 2022, 09:10:57 am ---https://wiki.lazarus.freepascal.org/LazMapViewer

--- End quote ---
Yes I know that; He is my mentor in achieving the ability to understand the operation of tile maps and write related applications.By the way; Salute to the writers.


--- Quote from: MarkMLl on November 08, 2022, 09:10:57 am ---Apart from that, what's needed is a massive amount of input data and an excellent understanding of spherical geometry as applied to the geoid.

--- End quote ---
Is it necessary to have education in the relevant engineering branch in order to understand the subjects you have mentioned?
What should a computer programmer do to realize this?
For example, where to start and how far to go for the use of Opengl on google earth...
Again, for the same Opengl usage, can the above mastery be reached with the information available in the market?

MarkMLl:
I think that understanding the principles behind the various projections that different data sources use to project their datasets (and this includes the pixels of a photograph) onto the sphere (strictly, the geoid) is unavoidable. I believe that's where the concept of a manifold comes into it: in this case it's the overall collection of maths which determines how non-spherical data is projected onto the sphere, and how the sphere is projected onto the viewing plane. And this is something that the QGIS community has put a lot of work into.

Although I'm obviously not privy to the sourcecode, I believe that this is something that Google Maps is not particularly good at: they work by recognising and blending features in the photographs and maps they've bought in (or hijacked, in the case of sources like the USGS and OSM). I don't know for certain but I /suspect/ that Google Earth- and I mean the traditional program running on a local computer here rather than the recent "cloud-based" reinvention- is somewhat better since it at least started off as a decent GIS system written by people who appeared to know what they were doing.

I suspect that it's possible to brush a lot of problems under the carpet if the border between datasets is over something featureless like a major ocean (i.e. with no inconvenient islands). It's not if you want to handle borders properly (as an unchecked example, between European and Russian conventions), and it's not if you want to be able to overlay images such as the charts found at https://www.weathercharts.org/ukmomslp.htm (Conformal Conic projection).

If you're really unfamiliar with this stuff, https://en.wikipedia.org/wiki/Spatial_reference_system is an OKis starting point, although I'd suggest jumping to the "Worldwide" section and looking at the examples given before going back to the main article.

MarkMLl

loaded:

--- Quote from: MarkMLl on November 08, 2022, 12:08:29 pm ---If you're really unfamiliar with this stuff, https://en.wikipedia.org/wiki/Spatial_reference_system is an OKis starting point, although I'd suggest jumping to the "Worldwide" section and looking at the examples given before going back to the main article.

--- End quote ---
It is difficult for me to grasp this subject on my own, it seems like it will be necessary to study Engineering.  ;D
Anyway, thank you very much for the valuable information you have given, master MarkMLl

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