如何在Python中用GDAL Translate自动缩放并保存为JPG？

Got it, let's break down how to replicate your gdal_translate command behavior perfectly in Python using gdal.Translate!

The Problem Recap #

Your CMD command uses -scale without any explicit min/max values, which tells GDAL to automatically calculate the input image's pixel value range, then linearly stretch that range to the default 0-255 (ideal for 8-bit JPEG output). You want to mirror this in Python, but weren't sure how to set scaleParams or related options.

The Solution Code #

Here's the exact Python equivalent of your CMD command:

from osgeo import gdal

img_bsq = 'image.bsq'
img_jpg = 'image.jpg'

# Replicate gdal_translate -of JPEG -outsize 10% 10% -scale
gdal.Translate(
    destName=img_jpg,
    srcDS=img_bsq,
    format='JPEG',
    widthPct=10,  # Matches -outsize 10% (width percentage)
    heightPct=10, # Matches -outsize 10% (height percentage)
    scale=True    # Matches bare -scale: auto-calculate input range, stretch to 0-255
)

Key Details Explained #

1. Scaling the Image Size:

   • Instead of hardcoding width=1024, use widthPct=10 and heightPct=10 to mirror the -outsize 10% 10% behavior. This ensures proportional scaling based on the original image's dimensions, just like the CMD command.

2. Automatic Value Stretching:

   • The scale=True parameter is exactly equivalent to the bare -scale in your CMD command. GDAL will:
     1. Automatically compute the minimum and maximum pixel values of your input image.bsq
     2. Linearly map that input range to the default output range of 0-255 (perfect for JPEG's 8-bit format)
   • If you ever wanted to explicitly define the output range (though you don't need it here), you could use scaleParams=[[]] (empty inner list triggers auto input range calculation, default output 0-255). But scale=True is more readable for this use case.

3. Multi-Band Images:

   • If your .bsq has multiple bands, scale=True will apply the auto-stretch to every band individually. If you wanted to customize per-band scaling, you could pass scaleParams=[[], [], []] (one empty list per band) to keep auto-calculation for each.

内容的提问来源于stack exchange，提问作者KcFnMi