Controu plot from matlab table

3 views (last 30 days)
Morten Nissov
Morten Nissov on 18 Mar 2021
Commented: Morten Nissov on 9 Apr 2021
I have a table with values extracted from a csv I want to make a contour plot from.
Let's use this table as an example
tdata.x = [1;2;1;2];
tdata.y = [3;3;4;4];
tdata.z = randn(4,1);
tdata=struct2table(tdata);
>> tdata
tdata =
4×3 table
x y z
_ _ _______
1 3 0.53767
2 3 1.8339
1 4 -2.2588
2 4 0.86217
I would like to pivot this such that I can use it for plotting a contour, so in principle I want a 2x2 z matrix where rows/columns are given by y and x respectively, something in this direction:
x 1 2
y
3 0.53767 1.8339
4 -2.2588 0.86217

Answers (1)

KSSV
KSSV on 18 Mar 2021
x = T.x ;
y = T.y ;
z = T.z ;
nx = length(unique(x)) ;
ny = length(unique(y)) ;
X = reshape(x,nx,ny) ;
Y = reshape(y,nx,ny) ;
Z = reshape(z,nx,ny) ;
contour(X,Y,Z)
  9 Comments
KSSV
KSSV on 9 Apr 2021
The gird looks fine when you use
scatter(X(:),Y(:),[],Z(:),'.')
Show me the PAndas code which worked for you.
Morten Nissov
Morten Nissov on 9 Apr 2021
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
df = pd.read_csv('EMAG2_faaborg.csv')
df = df[['lat','lon','upCont']].pivot('lat','lon')
lon = df.columns.levels[1].values
lat = df.index.values
vals = df.values
X,Y = np.meshgrid(lon, lat)
then I can plot using
plt.contourf(X, Y, vals)

Sign in to comment.

Categories

Find more on Geographic Plots in Help Center and File Exchange

Products


Release

R2020b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!