I would like to write a cycle which takes a current pixel, look at the surrounding pixels, choose the pixel with max/min value and skip to that pixel…and so on.
Is there in arcpy such a function which can work with pixel's neighborhood?
[GIS] way to find out which pixel values are around the current pixel
arcgis-desktoparcpypythonraster
Related Solutions
Here is a pure raster solution in Python 2.7 using numpy and scipy:
import numpy as np
from scipy import ndimage
import matplotlib.pyplot as plt
#create tree location matrix with values indicating crown radius
A = np.zeros((120,320))
A[60,40] = 1
A[60,80] = 2
A[60,120] = 3
A[60,160] = 4
A[60,200] = 5
A[60,240] = 6
A[60,280] = 7
#plot tree locations
fig = plt.figure()
plt.imshow(A, interpolation='none')
plt.colorbar()
#find unique values
unique_vals = np.unique(A)
unique_vals = unique_vals[unique_vals > 0]
# create circular kernel
def createKernel(radius):
kernel = np.zeros((2*radius+1, 2*radius+1))
y,x = np.ogrid[-radius:radius+1, -radius:radius+1]
mask = x**2 + y**2 <= radius**2
kernel[mask] = 1
return kernel
#apply binary dilation sequentially to each unique crown radius value
C = np.zeros(A.shape).astype(bool)
for k, radius in enumerate(unique_vals):
B = ndimage.morphology.binary_dilation(A == unique_vals[k], structure=createKernel(radius))
C = C | B #combine masks
#plot resulting mask
fig = plt.figure()
plt.imshow(C, interpolation='none')
plt.show()
Input:
Output:
You could do a first loop for the min and max values using getRasterproperties. Example for the max value below (min can be done in the same loop).
max_value=0
for raster in rasters:
max_val_tmp = int(arcpy.GetRasterProperties_management(raster, "MAX").getOutput(0))
if max_val_tmp > max_value:
max_value = max_val_tmp
Best Answer
What about using Get Cell Value with offsets equal to the cell size as location_point? E.g. if the coordinates of the center of your pixel of interest are (x, y) and the cell size of your raster is 10, you run the tool for (x - 10, y), (x + 10, y), (x, y - 10) and so on, add every result to a list and select the min or max value from the list.