HillshadeComparison.py

# -*- coding: utf-8 -*-
"""
Created on Tue Jan 31 11:47:22 2017

An example of using the cython version of the hillshade
algorithm from LSDTopoTools/LSDRaster, compared to the pure python
module in LSDMappingTools.

(This test version dos on-the-fly-compilation to C and then a C-lib
but you could bundle a compiled c-object with the code for speed/convenience)

@author: dav
"""
import matplotlib.pyplot as plt
# For on the fly compilation - remove if you are pre-compiling the Cython-library
# e.g. with a setup.py script that builds your cython extension library
# This MUST come before you import the C hillshade pyx file if you are doing it
# this way.
####################
import pyximport
pyximport.install()
####################

from LSDPlottingTools import fast_hillshade as fasthill
import LSDPlottingTools.LSDMap_GDALIO as LSDMap_IO
import LSDPlottingTools.LSDMap_BasicPlotting as LSDMap_BP

Directory = "/mnt/SCRATCH/Dev/ExampleTopoDatasets/"
BackgroundRasterName = "indian_creek.bil"

raster = LSDMap_IO.ReadRasterArrayBlocks(Directory + BackgroundRasterName)
data_res = LSDMap_IO.GetGeoInfo(Directory + BackgroundRasterName)[3][1]
try:
    NoDataValue = float(LSDMap_IO.getNoDataValue(Directory + BackgroundRasterName))
except TypeError:
    NoDataValue = -9999.0

ncols, nrows = raster.shape

# LSDMappingTools hillshade
#hs = LSDMap_BP.Hillshade(raster)
#plt.imshow(hs, cmap="gray")
#plt.show()

#LSDRaster Cythonised version pf hillshade
hs_nice = fasthill.Hillshade(raster, data_res, NoDataValue=NoDataValue)
# I tend to comment out these two lines profiling, so you
# aren't actually profiling the matplotlib rendering...
#plt.imshow(hs_nice, cmap="gray")
#plt.show()