Normalized Wind Rose Plot help
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I am trying to generate a normalized (to the max) wind rose plot of air pollutant concentration (UFP) by wind direction. See photo below. A data vector is attached. The simple code: polarplot(N.WD_Deg,N.UFPConc) doesn't generate what I want. Any help is appreciated. Thank you
load winddata.mat
polarplot(N.WD_Deg,N.UFPConc)
4 Comments
VBBV
on 23 Jun 2023
Try using polarhistogram function
One way is to use the data for air pollution concentration directly and compare with direction data as shown below
Data = load('winddata.mat')
Data.N;
%
subplot(121)
polarplot(Data.N.WD_Deg(1:10000:end),'linewidth',2,'Color','red')
title('Wind direction [deg]')
subplot(122) % normalized plot of air pollutant data
polarplot(Data.N.UFPConc(1:10000:end)./max(Data.N.UFPConc(1:10000:end)),'linewidth',2,'Color','red')
title('Air pollutant concentration')
since polarplot by default uses direction data for its axes, yoou can use that pollutant data directly. Othwerwise, you can also apply conditions for direction data bins and filter the air pollutant concentration data , then plot it. Further, the data points in the table are many, so its better to filter the air pollutant data using bin averaged directional means which will be representative of the air pollutant concentration
Douglas Leaffer
on 24 Jun 2023
Moved: VBBV
on 25 Jun 2023
Thank you VBBV and Star Strider. Both of your suggested codes worked for me - but I can't seem to rotate the compass points to have 0 at the top and then clockwise ticks, with 90 deg at right, 180 at bottom and 270 at left. Is there a simple programmatic fix for this?
E. Cheynet
on 25 Jun 2023
For the direction with meteorological conventions, you can simply give a new direction newD = 90-oldD
Accepted Answer
Perhaps something like this —
LD = load('winddata.mat');
N = LD.N;
N.WD_Rad = deg2rad(N.WD_Deg) % Add Radian Variable (For Convenience, Since 'polarplot' Requires It)
[UDir,ix,iv] = unique(N.WD_Rad); % Unique Radian Values & Indices (Sorted)
Concv = accumarray(iv, (1:numel(iv)).', [], @(x)numel(N.UFPConc(x))); % Accumulate Count Values Of 'UFPConc' By Direction (Use 'numel' To Count Occurrences)
[sDir, sConc] = stairs(UDir, Concv); % Return 'stairs' Stepwise Result
figure
polarplot(sDir, sConc) % Plot 'stairs' Stepwise Result
figure
polarplot(UDir, Concv) % Plot Continuous Result
figure
polarhistogram(N.WD_Rad, UDir) % Plot Using 'polarhistogram'
Make appropriate changes to get the result you want.
Using the accumarray function, it is possible to get other parameters of the concentration, such as the mean or median values, as well as standard deviations (std and metrics derived from it, such as confidence intervals) and plot them also using the patch function (although that is more complicated and requires calculating them in polar coordinates and then using the pol2cart function first, and plotting them in Cartesian coordinates), not only the counts.
.
4 Comments
Douglas Leaffer
on 24 Jun 2023
Thank you VBBV and Star Strider. Both of your suggested codes worked for me - but I can't seem to rotate the compass points to have 0 at the top and then clockwise ticks, with 90 deg at right, 180 at bottom and 270 at left. Is there a simple programmatic fix for this?
It is straightforward to add those using the ThetaZeroLocation and ThetaDir properties (that I believe existed before R2022a, so you should have them) —
LD = load('winddata.mat');
N = LD.N;
N.WD_Rad = deg2rad(N.WD_Deg) % Add Radian Variable (For Convenience, Since 'polarplot' Requires It)
[UDir,ix,iv] = unique(N.WD_Rad); % Unique Radian Values & Indices (Sorted)
Concv = accumarray(iv, (1:numel(iv)).', [], @(x)numel(N.UFPConc(x))); % Accumulate Count Values Of 'UFPConc' By Direction (Use 'numel' To Count Occurrences)
[sDir, sConc] = stairs(UDir, Concv); % Return 'stairs' Stepwise Result
figure
polarplot(sDir, sConc) % Plot 'stairs' Stepwise Result
Ax = gca;
Ax.ThetaZeroLocation = 'top';
Ax.ThetaDir = 'clockwise';
figure
polarplot(UDir, Concv) % Plot Continuous Result
Ax = gca;
Ax.ThetaZeroLocation = 'top';
Ax.ThetaDir = 'clockwise';
figure
polarhistogram(N.WD_Rad, UDir) % Plot Using 'polarhistogram'
Ax = gca;
Ax.ThetaZeroLocation = 'top';
Ax.ThetaDir = 'clockwise';
.
Douglas Leaffer
on 24 Jun 2023
Star Strider
on 24 Jun 2023
As always, my pleasure!
More Answers (1)
Douglas Leaffer
on 22 Dec 2023
Hello, it seems the plots generated from these suggested answers are not what I need. I need a normalized [0 1] wind rose of UFP (air pollution particle) by wind degree sector, as show in these 3 examples. My dataset is attached. The code I ran is given below. I could use some more help if anyone is able. Thank you.
load CR_1hr_wind.mat
NC = normalize(CT1,"norm",Inf,"DataVariables","UFPConc");
NC.WD_Rad = deg2rad(NC.WD_Deg) % Add Radian Variable (For Convenience, Since 'polarplot' Requires It)
[UDir,ix,iv] = unique(NC.WD_Rad); % Unique Radian Values & Indices (Sorted)
Concv = accumarray(iv, (1:numel(iv)).', [], @(x)numel(NC.UFPConc(x))); % Accumulate Count Values Of 'UFPConc' By Direction (Use 'numel' To Count Occurrences)
%[sDir, sConc] = stairs(UDir, Concv); % Return 'stairs' Stepwise Result
%figure
%polarplot(sDir, sConc)
figure
%subplot (121)
polarplot(UDir, Concv, 'LineWidth', 4) % Plot Continuous Result
Ax = gca;
Ax.ThetaZeroLocation = 'top';
Ax.ThetaDir = 'clockwise';
3 Comments
To normalise them, divide by the maximum:
Concv = Concv/max(Concv);
Try this —
load CR_1hr_wind.mat
NC = normalize(CT1,"norm",Inf,"DataVariables","UFPConc");
NC.WD_Rad = deg2rad(NC.WD_Deg) % Add Radian Variable (For Convenience, Since 'polarplot' Requires It)
[UDir,ix,iv] = unique(NC.WD_Rad); % Unique Radian Values & Indices (Sorted)
Concv = accumarray(iv, (1:numel(iv)).', [], @(x)numel(NC.UFPConc(x))); % Accumulate Count Values Of 'UFPConc' By Direction (Use 'numel' To Count Occurrences)
%[sDir, sConc] = stairs(UDir, Concv); % Return 'stairs' Stepwise Result
%figure
%polarplot(sDir, sConc)
Concv = Concv/max(Concv);
figure
%subplot (121)
polarplot(UDir, Concv, 'LineWidth', 4) % Plot Continuous Result
Ax = gca;
Ax.ThetaZeroLocation = 'top';
Ax.ThetaDir = 'clockwise';
If you intend something else, please be specific.
.
Douglas Leaffer
on 22 Dec 2023
Star Strider
on 22 Dec 2023
As always, my pleasure!
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