Arcpy Condition on Green Band of Raster Dataset - Incorrect Results

NickCollis1 — Fri, 02 May 2025 08:22:31 GMT

There is a multi-band raster dataset, IN_RASTER, split into four bands of RGB and an alpha band. A script tool is written to pull out the green band of IN_RASTER, and run Conditional on it to return a raster of 0 for all cells where the input is outside of a given range. A range of values for the green band is given, with Con returning 0 for any values outside of this range:

from arcpy.ia import ExtractBand
from arcpy.sa import Con

IN_RASTER = "C:/Users/mallard/mallards_input_colour_raster.tif"
GREEN_RANGE = [100, 200]

green_band = ExtractBand(raster=IN_RASTER, band_names=["green"])

s = GREEN_RANGE[0]
e = GREEN_RANGE[1]
green_filtered = Con((green_band >= s) & (green_band <= e), green_band, 0)
green_filtered.save()

The output, green_filtered, is compared to the input raster using ArcGIS Pro. See screenshot, showing the input raster, zoomed in to show four whole cells:

Identify is run on the top-right cell:

This shows a value of 125 for the green band. This is within the range GREEN_RANGE used in the Con tool. As such, this cell's value of 125 should be returned in the green_filtered output raster. However, inspecting this same cell in the output raster, its value is zero:

What is the error in the code or the approach?

Re: Arcpy Condition on Green Band of Raster Dataset - Incorrect Results

JohannesBierer — Mon, 12 May 2025 11:45:27 GMT

Are there brackets missing in the con statemant?

Con(((inRaster1 == 1) & (inRaster2 == 5)), inRaster1 + inRaster2, 99)

https://desktop.arcgis.com/de/arcmap/latest/tools/spatial-analyst-toolbox/con-.htm

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Arcpy Condition on Green Band of Raster Dataset - Incorrect Results

Re: Arcpy Condition on Green Band of Raster Dataset - Incorrect Results