Matrix rotate

The example for matrix rotate.

#Plot
axesm(tickfontsize=12)
geoshow('country', edgecolor='k')

#Original matrix
lat = arange(10, 41, 5)
lon = arange(70, 131, 5)
lon, lat = meshgrid(lon, lat)
scatter(lon, lat, facecolor='b', size=8, edge=False)

#Rotate matrix
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
scatter(xy[:,0], xy[:,1], facecolor='r', size=8, edge=False)

xticks(arange(0, 361, 10))
yticks(arange(-90, 91, 10))
title('Matrix rotate sample')
xlim(50, 150)
ylim(0, 70)