Simulate Circle which center is at real Lat and Lon

I want to put a circle at specific center with latitude and longitude with a known radius.

However I dont have any idea how to make it. Because latitude/longitude can be negative/positive all the time, what varies is the distance. So I dont know how to simulate my position based on the circle.

It is posible to do something like in the image in matlab? http://tinypic.com/r/a0x5jr/5

Answer 1

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_do_I_create_a_circle.3F

Negative and positive coordinates are common when drawing circles...

[SpcCode]

What about making the x and y coordinates of the circle at the correct location of the earth ? Thats what I really want.

[Walter Roberson]

Construct a circle of the correct radius centered around (0,0), then add the longitude to x and the latitude to y (if you are using the convention that north corresponds to increasing y values.)