Files
met_office_radar_data/modules/generate_timeseries.py
T
2025-11-18 21:30:10 +00:00

166 lines
6.3 KiB
Python

from __future__ import division, print_function
import numpy as np
from pathlib import Path
import polars as pd
from datetime import datetime
import os
class GenerateTimeseries:
def __init__(self, config):
self.config = config
def _read_ascii_header(self, ascii_raster_file: str) -> list:
"""Reads header information from an ASCII DEM
Args:
ascii_raster_file (str): Path to the ASCII raster file
Returns:
list: Header data as a list of floats
"""
with open(ascii_raster_file) as f:
header_data = [float(f.__next__().split()[1]) for x in range(6)]
return header_data
def _calculate_crop_coords(self, basin_header: list, radar_header: list) -> tuple:
"""Calculate crop coordinates based on header data
Args:
basin_header (list): Basin header data
radar_header (list): Radar header data
Returns:
tuple: (start_col, start_row, end_col, end_row) as integers
"""
y0_radar = radar_header[3]
x0_radar = radar_header[2]
y0_basin = basin_header[2]
x0_basin = basin_header[1]
nrows_radar = radar_header[1]
nrows_basin = 2 # hardcoded, likely to change?
ncols_basin = 2 # hardcoded, likely to change?
cellres_radar = radar_header[4]
cellres_basin = 1000 # 1km
xp = x0_basin - x0_radar
yp = y0_basin - y0_radar
xpp = ncols_basin * cellres_basin
ypp = nrows_basin * cellres_basin
start_col = np.floor(xp / cellres_radar)
end_col = np.ceil((xpp + xp) / cellres_radar)
start_row = np.floor(nrows_radar - ((yp + ypp) / cellres_radar))
end_row = np.ceil(nrows_radar - (yp / cellres_radar))
return int(start_col), int(start_row), int(end_col), int(end_row)
def extract_data_for_all_locations(self, locations):
"""Extract cropped rain data for all locations by iterating over ASC files once.
Args:
locations (list): List of location data [zone_id, easting, northing, zone]
"""
# Initialize data structure to hold results: {zone_id: {'dates': [], 'values': []}}
results = {loc[0]: {'dates': [], 'values': []} for loc in locations}
# Get list of ASC files and sort them to ensure chronological order if needed
asc_files = sorted(os.listdir(Path(self.config.ASC_TOP_FOLDER)))
total_files = len(asc_files)
print(f"Processing {total_files} ASC files...")
for i, file_name in enumerate(asc_files):
if not file_name.endswith('.asc'):
continue
file_path = Path(self.config.ASC_TOP_FOLDER, file_name)
try:
radar_header = self._read_ascii_header(str(file_path))
# Read grid once
cur_rawgrid = np.loadtxt(file_path, skiprows=6, dtype=float, delimiter=None)
# Parse datetime from filename once
filename = os.path.basename(file_path)
date_str = filename[:8] # YYYYMMDD
time_str = filename[8:12] # HHMM
parsed_date = datetime.strptime(f"{date_str}{time_str}", "%Y%m%d%H%M")
# Extract data for each location
for location in locations:
zone_id = location[0]
# Calculate crop coordinates
start_col, start_row, end_col, end_row = self._calculate_crop_coords(
location, radar_header
)
# Extract value
# Note: The original code used cur_croppedrain.flatten()[2] / 32
# We need to ensure the crop is valid and has enough elements.
# Assuming the crop size is fixed as per original code (2x2 basin -> 4 cells?)
# Original:
# nrows_basin = 2
# ncols_basin = 2
# cellres_basin = 1000
# cellres_radar = radar_header[4] (usually 1000)
# So it's likely a small grid.
cur_croppedrain = cur_rawgrid[start_row:end_row, start_col:end_col]
# Original logic: rainfile.append(cur_croppedrain.flatten()[2] / 32)
# We replicate this exactly.
if cur_croppedrain.size > 2:
val = cur_croppedrain.flatten()[2] / 32
else:
val = 0.0 # Handle edge case if crop is too small? Or maybe NaN?
# For now, let's assume it works as before, but maybe add a check?
# If the original code worked, this should work too provided indices are correct.
# If size is too small, it would raise IndexError in original code too.
if cur_croppedrain.size <= 2:
print(f"Warning: Crop too small for {zone_id} in {file_name}")
val = 0.0 # Default or error?
results[zone_id]['dates'].append(parsed_date)
results[zone_id]['values'].append(val)
except Exception as e:
print(f"Error processing file {file_name}: {e}")
continue
if (i + 1) % 100 == 0:
print(f"Processed {i + 1}/{total_files} files")
# Write CSVs for each location
print("Writing CSV files...")
for location in locations:
zone_id = location[0]
data = results[zone_id]
if not data['dates']:
print(f"No data found for {zone_id}")
continue
df = pd.DataFrame({"datetime": data['dates'], zone_id: data['values']})
# Sort and set index (Polars)
sorted_df = df.sort("datetime")
sorted_df = sorted_df.with_columns(
pd.Series(data['dates']).alias("datetime")
).set_sorted("datetime")
output_path = Path(self.config.CSV_TOP_FOLDER) / f"{zone_id}_timeseries_data.csv"
sorted_df.write_csv(
output_path,
float_precision=4
)
print("All CSV files written.")