Blending images
We can make our results even more visually appealing and informative if we can combine the colorized image with the shaded relief image. Again, since we are dealing with arrays, we may deduce that this kind of composition can be achieved by performing an arithmetic operation between the two arrays.
In image processing, this is called alpha blending. Basically, a transparency is applied to both of the images and then they are blended into a new one. In the next steps, we are going to create a function that performs this operation:
First, to avoid generating the shaded relief multiple times, let's save it on the disk and edit the
if __name__ == '__main__':
block of theraster_data.py
file:if __name__ == '__main__': raster_data = RasterData('output/dem.tif') raster_data.adjust_values().create_hillshade( 10, 60).write_image('output/shaded.png')
Run the code and check whether the image was correctly written on the disk.
Now, add the
alpha_blend
method to theRasterData...