CODEWITHSUNDEEP
pythonmatplotlibkml
jolson
jolson

Reputation: 51

Export Python Plot to KML

How to create a lon/lat plot with Matplotlib that can be exported to Google Earth with points appearing on G.E. correctly. Image can be seen here: https://i.sstatic.net/S2BX7.jpg Google Earth view Seems like there is always a slight border around my exported figure such that the points I define in plot are off in G.E.

x = [0, 10, 10, 0, 0]
y = [10, 10, 0, 0, 10]
x1=[0,1,2,3,4,5,6,7,8,9,10]

fig = Figure(facecolor=None, frameon=False)
ax = fig.add_axes([0,0,1,1])
ax.axis('off')

ppl.plot(x, y, 'r',  axes=ax)
ppl.plot(x, y, '.b', axes=ax)
ppl.plot(x1, x1, 'g', axes=ax)

ppl.axis('off')
ppl.tight_layout(0,h_pad=0, w_pad=0)
border1 = ppl.axis(bbox_inches='tight')
ppl.show()

pngName = 'temp.png'
py.savefig(pngName, bbox_inches='tight', pad_inches=0, transparent=True)

bottomleft  = (border1[0],border1[2])
bottomright = (border1[1],border1[2])
topright    = (border1[1],border1[3])
topleft     = (border1[0],border1[3])

kml = simplekml.Kml()
ground = kml.newgroundoverlay(name='GroundOverlay')
ground.icon.href = pngName
ground.gxlatlonquad.coords =[bottomleft, bottomright, topright, topleft]
kml.save("GroundOverlay_temp.kml")

Upvotes: 5

Views: 1448

Answers (1)

Glenn N
Glenn N

Reputation: 845

I have a solution, but I'm not familiar enough with Figure and Artist classes to give a clear explanation of why it is correct.

You need to do these two things:

  1. Use fig = ppl.figure() instead of matplotlib.figure.Figure().
  2. Save with fig.savefig() instead of ppl.savefig().

Also use of tight_layout and padding is not needed. I also set facecolor for the figure so that I can see the true boundaries. View the output image, temp.png, with an image viewer and you should see that the rectangle borderlines are at the figure edges; when I ran your original code and viewed the image, there was always some small amount of space between rectangle and figure bounds.

Here is the fixed code:

import matplotlib
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as ppl
from pylab import rcParams
import simplekml
rcParams['figure.figsize'] = (8,8)
# create rectangle over 0 to 10 degrees longitude and 0 to 10 degrees latitude
x = [0, 10, 10, 0, 0]
y = [10, 10, 0, 0, 10]
x1=range(0,11)    # to draw a diagonal line

fig = ppl.figure(1)
ax = fig.add_axes([0,0,1,1])
ax.axis('off')
fig.patch.set_facecolor('blue')  # so we can see the true extent

ppl.plot(x, y, 'r', linewidth=3)
ppl.plot(x, y, '.b', linewidth=3)
ppl.plot(x1, x1, 'g', linewidth=3)

ppl.axis('off')
border1 = ppl.axis()
print 'Border = %s' %(str(border1))
if False:
    ppl.show()
else:
    pngName = 'Overlay.png'
    fig.savefig(pngName, facecolor=fig.get_facecolor(), transparent=False)

bottomleft  = (border1[0],border1[2])
bottomright = (border1[1],border1[2])
topright    = (border1[1],border1[3])
topleft     = (border1[0],border1[3])

kml = simplekml.Kml()
ground = kml.newgroundoverlay(name='GroundOverlay')
ground.icon.href = pngName
ground.gxlatlonquad.coords =[bottomleft, bottomright, topright, topleft]
kml.save("GroundOverlay.kml")

Upvotes: 2

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