record pixel value with Python script

[maxerickson at gmail.com]

On Saturday, January 11, 2014 5:53:00 PM UTC-5, DPod wrote:

> 
> I'd like to write a Python script for ArcGIS 10.x (ArcPy or Python 2.6.5) >that would record the pixel value for all pixels in a raster. Furthermore, I'd >like to only record a given value once in the results. For example, if there >are 23 values of 180 overall, only record one instance of that value.
> 
> The raster in question is 4-band (6017 x 7715 pixels) so the results would >have to include values for all pixels in each band, recorded separately by >band. Ideally I'd like to write to an Excel file or at least a .csv file.
> 

Can you install libraries?

Fetching the pixel values of an individual band is straightforward in PIL (and the fork Pillow), something like this:

from PIL import Image
im=Image.open("blah.jpg")
red=im.getdata(0)

If you can't install things you would need to figure out if ArcGIS has an API for fetching a band.

The filtering step is easy, you just want the set of values:

set(red)


Max