How to correctly convert the length in rectangular coordinates to the wgs84 projection?

Question

C++ / C#

Good afternoon!
I am writing a small program. It specifies a polygon, in wgs84 projection coordinates. It looks something like this:

I have some distance (set by the number of meters), and I need to draw this distance from one point of this polygon, and as I understand it, I need to convert the length of the distance in rectangular coordinates to the WGS84 projection. I can't figure out how to do this, please help.

Answer 1

The question is how exactly do you need to calculate.
As a first and simplest approximation, you can use the following:
For a polygon point with given X, Y coordinates, calculate approximate conversion factors to meters for that point.
For latitude it is about 6356752/360~17657 meters per degree
For longitude it is calculated depending on latitude, for each point separately: 6378137/360 * cos(latitude
) 0000; 37.0000) per 1000 meters, then:
17657 meters per degree of latitude gives us a distance of 0.056634762 degrees per 1000 meters
For longitude: 6 378 137/360 * cos(55 degrees) ~ 10162 meters per degree, which gives 0.098405826 degrees per 1000 meters.
In total, the points we need lie within 55 + dY; 37+dY, where (dx/0.056634762)^2 + (dy/0.098405826)^2 < 1000^2
The calculations are approximate, and probably with errors, but the general meaning should be clear. The accuracy of these calculations is about a meter, you need more - consider more precisely. With increasing distances, the curvature of the earth will begin to affect and this method will become completely inaccurate.

Answer 2

Use proj4 (and version 5 has already been released). Convert your latitude/longitude to meters, such as UTM. Add the required meters to it. Convert back to latitude/longitude.