Kate
2009-03-17 13:21:01 UTC
Hello everyone,
I would really appreciate some help with this. This problem came up while writing a program to calculate the luminance distribution over the sky at a given time for my 4th year project (I’m a mechanical engineering student at Manchester, UK).
I have calculated the relative luminance for a sky, as modelled as a hemisphere. So I defined two angles: x=linspace(0,2*pi,360) and y=linspace(0,pi/2,360) with x being the angle of azimuth of a point and y being the angle of elevation from the horizon up to the zenith. I calculated my relative luminance for each combination in a for loop, so I have RelLum as a 360x360 matrix. What I want to do is draw a circular contour map of the Relative luminance, with the angle of elevation gong from 0 to 2pi around the edge of the plot. If you google "Typical clear sky luminance pattern in the plan projection of the sky vault normalised to zenith", the first image you see will give you an example of what I want. At the moment, my contour plot is square, with the x being on one axis and y on the other.
As it stands the data is in a square, Cartesian form and I want it to become circular as shown in the example. As RelLum is defined by a full 2pi of angles, this should be easy but I cannot figure out how to do it. If someone could help me I would be extremely grateful. I’m not an experienced Matlab users and so not an experienced poster, please let me know if there’s anything else you need from me to figure it out.
I would really appreciate some help with this. This problem came up while writing a program to calculate the luminance distribution over the sky at a given time for my 4th year project (I’m a mechanical engineering student at Manchester, UK).
I have calculated the relative luminance for a sky, as modelled as a hemisphere. So I defined two angles: x=linspace(0,2*pi,360) and y=linspace(0,pi/2,360) with x being the angle of azimuth of a point and y being the angle of elevation from the horizon up to the zenith. I calculated my relative luminance for each combination in a for loop, so I have RelLum as a 360x360 matrix. What I want to do is draw a circular contour map of the Relative luminance, with the angle of elevation gong from 0 to 2pi around the edge of the plot. If you google "Typical clear sky luminance pattern in the plan projection of the sky vault normalised to zenith", the first image you see will give you an example of what I want. At the moment, my contour plot is square, with the x being on one axis and y on the other.
As it stands the data is in a square, Cartesian form and I want it to become circular as shown in the example. As RelLum is defined by a full 2pi of angles, this should be easy but I cannot figure out how to do it. If someone could help me I would be extremely grateful. I’m not an experienced Matlab users and so not an experienced poster, please let me know if there’s anything else you need from me to figure it out.