.. _examples-meteoinfolab-meteo_analysis-ave_rect:

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Average data along x/y axis of a rectangle
******************************************

Average data along x/y axis of a ractangle, and plot vertical distribution of the average data.

::

    f = addfile('D:/Temp/nc/uwnd.2011.nc')
    data = f['uwnd'][0,:,'10:40','70:130']
    data = mean(data, axis=1)
    lev1 = data.dimvalue(0)
    #lev2 = 1000 - lev1
    lev2 = p2h(lev1)
    levels = []
    for i in range(0, len(lev1)):
        levels.append('%i' % lev1[i])
    data.setdimvalue(0, lev2)
    #Plot
    layer = contourf(data, 20)
    colorbar(layer)
    yticks(lev2, levels)
    xlabel('Longitude')
    ylabel('Pressure (hPa)')
    title('Latitude average uwnd profile')
    
.. image:: ../../../_static/ave_rect_profile.png

Rotated rectangle::

    #Read data array
    f = addfile('D:/Temp/nc/uwnd.2011.nc')
    data = f['uwnd'][0,:,'0:70','50:150']

    #Get rotated grid
    lat = arange(10, 41, 5)
    lon = arange(70, 131, 5)
    xn = len(lon)
    yn = len(lat)
    lon, lat = meshgrid(lon, lat)
    angle = 20 * pi / 180
    rotate = array([[cos(angle),sin(angle)], [-sin(angle),cos(angle)]])
    n = len(lon)
    xy = zeros([n, 2])
    xy[:,0] = lon - 70
    xy[:,1] = lat - 10
    xy = dot(xy, rotate)    #Matrix multiplication
    xy[:,0] = xy[:,0] + 70
    xy[:,1] = xy[:,1] + 10
    lon[:,:] = xy[:,0]
    lat[:,:] = xy[:,1]

    #Project data to the grid
    ndata = data.project(lon, lat)

    #Average data along tilt latitude
    londata = mean(ndata, axis=1)
    latdata = mean(ndata, axis=2)
    lev1 = data.dimvalue(0)
    lev2 = p2h(lev1)
    levels = []
    for j in range(0, len(lev1)):
        levels.append('%i' % lev1[j])

    #Plot
    subplot(2,1,1)
    layer = contourf(lon[0,:], lev2, londata, 20)
    colorbar(layer)
    yticks(lev2, levels)
    xlabel('Longitude')
    ylabel('Pressure (hPa)')
    title('Tilt latitude average uwnd profile')

    subplot(2,1,2)
    layer = contourf(lat[0,:], lev2, latdata, 20)
    colorbar(layer)
    yticks(lev2, levels)
    xlabel('Latitude')
    ylabel('Pressure (hPa)')
    title('Tilt longitude average uwnd profile')
    
.. image:: ../../../_static/ave_rect_tilt_profile.png