About learning algorithm

Rookiemin commented 3 years ago

Hello,dear author. Recently I am studying your algorithm in demo, but due to the limited level, I can't understand some algorithm . Could you please tell me which algorithms are used in this demo? I want to study this demo further. Thanks any way!

RaymanNg commented 3 years ago

I have written some comment about the algorithm I used in the GLSL code. The key algorithms I used are listed below:

Bilinear interpolation https://en.wikipedia.org/wiki/Bilinear_interpolation
Runge Kutta second order https://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods#Second-order_methods_with_two_stages
unit conversion: meters -> longitude latitude degrees https://en.wikipedia.org/wiki/Geographic_coordinate_system#Length_of_a_degree
WGS84 (lon, lat, lev) -> ECEF (x, y, z) https://en.wikipedia.org/wiki/Geographic_coordinate_conversion#From_geodetic_to_ECEF_coordinates

P.S. It might be better if you ask about a specified algorithm you don't understand so that I can give you a more helpful answer

Rookiemin commented 3 years ago

Hello，dear author. Could you explain to me why use the convert Coordinate algorithm( WGS84 (lon, lat, lev) -> ECEF (x, y, z) )? I have a question, can the particle position be directly expressed in latlonlev? Thank you very much for your guidance.

RaymanNg commented 3 years ago

Could you explain to me why use the convert Coordinate algorithm( WGS84 (lon, lat, lev) -> ECEF (x, y, z) )?

The coordinate system of WebGL is Cartesian coordinate system, not WGS84, I have to convert WGS84 to XYZ for rendering

can the particle position be directly expressed in latlonlev?

I am afraid not, you have to render with the coordinate system of WebGL

Rookiemin commented 3 years ago

Can I convert the coordinate system to a two-dimensional Cartesian coordinate system? If so, could you provide me with an algorithm formula?

------------------ 原始邮件 ------------------ 发件人: "RaymanNg/3D-Wind-Field" <notifications@github.com>; 发送时间: 2020年12月17日(星期四) 上午9:10 收件人: "RaymanNg/3D-Wind-Field"<3D-Wind-Field@noreply.github.com>; 抄送: "啥也不会的小菜鸟"<984281379@qq.com>;"Author"<author@noreply.github.com>; 主题: Re: [RaymanNg/3D-Wind-Field] About learning algorithm (#52)

Could you explain to me why use the convert Coordinate algorithm( WGS84 (lon, lat, lev) -> ECEF (x, y, z) )?

The coordinate system of WebGL is Cartesian coordinate system, not WGS84, I have to convert WGS84 to XYZ for rendering

can the particle position be directly expressed in latlonlev?

I am afraid not, you have to render with the coordinate system of WebGL

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RaymanNg commented 3 years ago

Can I convert the coordinate system to a two-dimensional Cartesian coordinate system?

Could you elaborate your question? From which coordinate system you want to convert to 2D Cartesian coordinate system? And why converting to 2D? 2D is just a special case of 3D.

Rookiemin commented 3 years ago

sorry，I didn't describe it clearly。 Firstly，I am trying whether this demo can be converted into a 2D wind field。 So, I thought about converting the wgs84 coordinate system in webgl into a 2D coordinate system. See what the result looks like。 Could you give me some suggestions?

Thank you anyway！ ------------------ 原始邮件 ------------------ 发件人: "RaymanNg/3D-Wind-Field" <notifications@github.com>; 发送时间: 2020年12月17日(星期四) 晚上6:15 收件人: "RaymanNg/3D-Wind-Field"<3D-Wind-Field@noreply.github.com>; 抄送: "啥也不会的小菜鸟"<984281379@qq.com>;"Author"<author@noreply.github.com>; 主题: Re: [RaymanNg/3D-Wind-Field] About learning algorithm (#52)

Can I convert the coordinate system to a two-dimensional Cartesian coordinate system?

Could you elaborate your question? From which coordinate system you want to convert to 2D Cartesian coordinate system? And why converting to 2D? 2D is just a special case of 3D.

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RaymanNg commented 3 years ago

What do you mean by 2D wind field? To draw particle trails on the surface of the Earth?

Rookiemin commented 3 years ago

Achieve a 2D wind field effect------------------ 原始邮件 ------------------ 发件人: "Rayman"<notifications@github.com> 发送时间: 2020年12月18日(星期五) 下午4:25 收件人: "RaymanNg/3D-Wind-Field"<3D-Wind-Field@noreply.github.com>; 抄送: "Rookiemin"<984281379@qq.com>;"Author"<author@noreply.github.com>; 主题: Re: [RaymanNg/3D-Wind-Field] About learning algorithm (#52)

RaymanNg commented 3 years ago

Did you mean render 2D map like this example?

If so, then this is unfortunately not supported by this demo for the moment, you may refer to issue #18 to get some detail.

Rookiemin commented 3 years ago

Could you explain in detail why that effect cannot be achieved?

------------------ 原始邮件 ------------------ 发件人: "RaymanNg/3D-Wind-Field" <notifications@github.com>; 发送时间: 2020年12月21日(星期一) 晚上10:40 收件人: "RaymanNg/3D-Wind-Field"<3D-Wind-Field@noreply.github.com>; 抄送: "啥也不会的小菜鸟"<984281379@qq.com>;"Author"<author@noreply.github.com>; 主题: Re: [RaymanNg/3D-Wind-Field] About learning algorithm (#52)

Did you mean render 2D map like this example?

If so, then this is unfortunately not supported by this demo for the moment, you may refer to issue #18 to get some detail.

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RaymanNg commented 3 years ago

I am afraid not, because I am not familiar with 2D rendering of Cesium. All I know is that 2D rendering of Cesium is quite different from that of 3D. I suggest that you should seek for help in Cesium Forum

RaymanNg / 3D-Wind-Field

About learning algorithm #52