Re-order the values in the x,y and z columns of a text file (e.g. a bathymetry .pts/.xyz file) such that they conform to a true .xyz format readable by GDAL and openable in QGIS.

to_xyz.py

import csv


"""
This script re-orders the values in the x,y and z columns of a text file (e.g. a bathymetry .pts/.xyz file) such that they conform to a true .xyz format readable by GDAL and openable in QGIS.

In many cases the data in an "xyz" file falls foul of the GDAL requirement that:
“Cells with same Y coordinates must be placed on consecutive lines. For a same Y coordinate value, the lines in the dataset must be organized by increasing X values.”
https://gdal.org/en/stable/drivers/raster/xyz.html
"""

# Define a function to reorder the file
def reorder_file(input_file, output_file):
    with open(input_file, 'r') as file:
        # reader = csv.reader(file, delimiter='\t')  # Read the tab-separated file
        reader = csv.reader(file, delimiter=' ')  # Read the space-separated file
        data = list(reader)  # Convert the file content to a list

    # Sort the data by the second column, then the first column
    data.sort(key=lambda row: (row[1], row[0]))

    # Write the sorted data to a new file
    with open(output_file, 'w', newline='') as file:
        writer = csv.writer(file, delimiter='\t')  # Use tab as the delimiter
        writer.writerows(data)

# Example usage
input_file = 'Bathymetry_1x1m.pts'  # Replace with your input file name
output_file = 'Bathymetry_1x1m_re-sorted.xyz'  # Replace with your desired output file name

reorder_file(input_file, output_file)