How to pass options in Python GDAL binding?

Question

I am trying to color a GeoTIFF file and convert it to PNG. Several thread (1, 2) have pointed the gdaldem function. Here I am now porting the function to Python. Using the documentation, I can pass DEMProcessingOptions to DEMProcessing.

How do I pass the DEMProcessingOptions object to DEMProcessing correctly? I have this on my code:

from osgeo import gdal

src_ds = gdal.Open('./example.tif')
options = gdal.DEMProcessingOptions(colorFilename='./color_ramp.txt', format='PNG')
ds = gdal.DEMProcessing('./example_converted.png', src_ds, processing='color-relief', options)

I get the error:

Cell In [7], line 3 ds = gdal.DEMProcessing('./example_converted.png', src_ds, processing='color-relief', options) ^ SyntaxError: positional argument follows keyword argument

If I remove the variable names in the function:

ds = gdal.DEMProcessing('./example_converted.png', src_ds, 'color-relief', options)

It would error:

TypeError: DEMProcessing() takes 3 positional arguments but 4 were given

Answer 1

The error thrown, indicates that you need to name the parameters with the correct keywords. try passing the options with this keyword:

from osgeo import gdal

src_ds = gdal.Open('./example.tif')
options = gdal.DEMProcessingOptions(colorFilename='./color_ramp.txt', format='PNG')
ds = gdal.DEMProcessing('./example_converted.png', src_ds, processing='color-relief', options=options)