xxq
437 lines
16 KiB
Python
437 lines
16 KiB
Python
"""
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降雨栅格服务
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负责降雨插值、边缘优化、PNG生成等业务逻辑
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"""
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import os
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import json
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from datetime import datetime
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from typing import Optional, List, Dict, Any, Tuple
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from io import BytesIO
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from app.utils.logger import get_logger
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class RainfallGridService:
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"""降雨栅格服务"""
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def __init__(self):
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"""初始化服务"""
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self.logger = get_logger()
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# 国标12小时累计降雨量等级和颜色映射
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self.rainfall_levels = {
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'levels': [0, 0.1, 5, 15, 30, 70, 140],
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'colors': [
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(200, 200, 200, 0), # 无雨
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(0, 0, 255, 0.4 * 255), # 小雨 (0.1-5mm)
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(0, 255, 255, 0.5 * 255), # 中雨 (5-15mm)
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(0, 255, 0, 0.89 * 255), # 大雨 (15-30mm)
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(255, 255, 0, 0.7 * 255), # 暴雨 (30-70mm)
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(255, 165, 0, 0.8 * 255), # 大暴雨 (70-140mm)
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(255, 0, 0, 0.9 * 255), # 特大暴雨 (140m+)
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],
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'labels': ['无雨', '小雨', '中雨', '大雨', '暴雨', '大暴雨', '特大暴雨']
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}
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# 西安地区大致边界（用于栅格范围）
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self.xian_bounds = {
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'min_lon': 107,
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'max_lon': 110,
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'min_lat': 33,
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'max_lat': 35,
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}
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# 栅格分辨率（度）
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self.grid_resolution = 0.01 # 约1km
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def _create_buffer_points(self, points_array) -> 'np.ndarray':
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"""
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创建缓冲点：在原始站点外围生成虚拟点以扩展插值区域
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Args:
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points_array: 原始站点坐标数组
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Returns:
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缓冲点坐标数组
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"""
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import numpy as np
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# 计算站点分布的中心
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center = np.mean(points_array, axis=0)
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# 在站点外围生成缓冲点（沿着各个方向扩展）
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buffer_points = []
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num_angles = 120 # 每隔3度生成一个缓冲点
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for angle_deg in range(0, 360, 360 // num_angles):
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angle_rad = np.radians(angle_deg)
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# 在凸包边界外扩展
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for scale in [1.05, 1.1, 1.15]:
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# 找到该方向上最远的站点
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direction = np.array([np.cos(angle_rad), np.sin(angle_rad)])
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projections = points_array @ direction
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max_idx = np.argmax(projections)
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# 在该方向上扩展
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base_point = points_array[max_idx]
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buffer_point = center + (base_point - center) * scale
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buffer_points.append(buffer_point)
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return np.array(buffer_points)
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def _calculate_adaptive_max_distance(
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self,
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points_array,
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base_distance: float = 0.3,
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min_distance: float = 0.15,
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max_distance: float = 0.5
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) -> float:
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"""
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根据站点密度自适应计算最大影响距离
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Args:
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points_array: 站点坐标数组
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base_distance: 基础距离
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min_distance: 最小距离
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max_distance: 最大距离
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Returns:
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自适应的最大影响距离
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"""
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import numpy as np
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from scipy.spatial import distance_matrix
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if len(points_array) < 3:
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return base_distance
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# 计算站点间的平均距离
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dist_matrix = distance_matrix(points_array, points_array)
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# 排除对角线（自身距离为0）
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np.fill_diagonal(dist_matrix, np.inf)
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avg_distance = np.mean(np.min(dist_matrix, axis=1))
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# 根据平均距离调整max_distance
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adaptive_distance = avg_distance * 3 # 约3倍平均站点间距
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# 限制在合理范围内
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return float(np.clip(adaptive_distance, min_distance, max_distance))
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def interpolate_rainfall(self, station_data: List[Dict[str, Any]]) -> Dict[str, Any]:
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"""
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使用优化的反距离权重法（IDW）进行降雨插值
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改进：
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1. 高斯核衰减替代简单幂律
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2. 自适应距离阈值
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3. 边缘渐变处理
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4. 高斯平滑减少突变
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Args:
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station_data: 站点数据列表
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Returns:
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插值结果字典
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"""
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import numpy as np
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from scipy.spatial import Delaunay, ConvexHull, distance_matrix
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from scipy.ndimage import gaussian_filter
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# 提取站点坐标和降雨量
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points_array = np.array([[s['lon'], s['lat']] for s in station_data])
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values_array = np.array([s['rainfall'] for s in station_data])
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# 创建栅格网格
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lon_range = np.arange(
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self.xian_bounds['min_lon'],
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self.xian_bounds['max_lon'],
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self.grid_resolution
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)
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lat_range = np.arange(
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self.xian_bounds['min_lat'],
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self.xian_bounds['max_lat'],
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self.grid_resolution
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)
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grid_lon, grid_lat = np.meshgrid(lon_range, lat_range)
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result = np.full_like(grid_lon, np.nan)
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# 自适应计算最大距离
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actual_max_distance = self._calculate_adaptive_max_distance(points_array)
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self.logger.info(f"使用最大影响距离: {actual_max_distance:.3f} 度")
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# 计算站点的凸包（带边缘缓冲）
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hull_mask = None
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confidence_mask = None
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if len(points_array) >= 3:
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try:
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# 创建缓冲站点：在原始站点外围添加虚拟点
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buffer_points = self._create_buffer_points(points_array)
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# 合并原始站点和缓冲站点
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all_points = np.vstack([points_array, buffer_points])
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# 计算凸包
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hull = ConvexHull(all_points)
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hull_points = all_points[hull.vertices]
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tri = Delaunay(hull_points)
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# 向量化判断所有网格点是否在凸包内
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grid_points = np.column_stack([grid_lon.ravel(), grid_lat.ravel()])
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hull_indices = tri.find_simplex(grid_points)
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hull_mask = hull_indices >= 0
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hull_mask = hull_mask.reshape(grid_lon.shape)
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# 计算置信度：基于到最近站点的距离
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grid_valid = grid_points[hull_mask.ravel()]
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if len(grid_valid) > 0:
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dist_to_stations = distance_matrix(grid_valid, points_array)
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min_distances = np.min(dist_to_stations, axis=1)
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# 创建置信度掩码（距离越远，置信度越低）
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confidence = np.ones(len(grid_points))
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confidence[hull_mask.ravel()] = np.exp(-min_distances / actual_max_distance)
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confidence_mask = confidence.reshape(grid_lon.shape)
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else:
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confidence_mask = np.ones_like(grid_lon)
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except Exception as e:
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self.logger.warning(f"凸包计算失败: {e}，使用全区域插值")
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hull_mask = np.ones_like(grid_lon, dtype=bool)
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confidence_mask = np.ones_like(grid_lon)
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else:
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hull_mask = np.ones_like(grid_lon, dtype=bool)
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confidence_mask = np.ones_like(grid_lon)
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# 向量化计算所有网格点到所有站点的距离
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lon_diff = grid_lon[:, :, np.newaxis] - points_array[np.newaxis, np.newaxis, :, 0]
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lat_diff = grid_lat[:, :, np.newaxis] - points_array[np.newaxis, np.newaxis, :, 1]
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distances = np.sqrt(lon_diff**2 + lat_diff**2)
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# 过滤超出最大距离的站点
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valid_mask = distances <= actual_max_distance
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# 对于每个网格点，检查是否有有效站点
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has_valid_stations = np.any(valid_mask, axis=2)
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# 合并凸包掩码和有效站点掩码
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final_mask = hull_mask & has_valid_stations
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# 避免除零
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distances = np.where(valid_mask, distances, np.inf)
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distances = np.maximum(distances, 1e-10)
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# 优化的权重计算：结合幂律和高斯衰减
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power = 2.0
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power_weights = 1.0 / (distances ** power)
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gaussian_weights = np.exp(-0.5 * (distances / (actual_max_distance * 0.5)) ** 2)
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# 混合权重：距离越远，高斯权重占比越大
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distance_ratio = distances / actual_max_distance
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mix_factor = np.clip(distance_ratio, 0, 1)
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weights = (1 - mix_factor) * power_weights + mix_factor * gaussian_weights
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weights = np.where(valid_mask, weights, 0)
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# 加权平均
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weighted_sum = np.sum(weights * values_array[np.newaxis, np.newaxis, :], axis=2)
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weight_total = np.sum(weights, axis=2)
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# 计算基础插值结果
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with np.errstate(divide='ignore', invalid='ignore'):
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result = np.where(
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final_mask & (weight_total > 0),
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weighted_sum / weight_total,
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np.nan
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)
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# 应用置信度调整：边缘区域向邻近值渐变
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if confidence_mask is not None:
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valid_rainfall = result[final_mask]
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if len(valid_rainfall) > 0:
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mean_rainfall = np.mean(valid_rainfall)
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# 根据置信度调整结果，低置信度区域向均值靠拢
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adjusted_result = result * confidence_mask + mean_rainfall * (1 - confidence_mask)
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result = np.where(final_mask, adjusted_result, np.nan)
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# 应用高斯平滑减少边缘突变
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result = gaussian_filter(result, sigma=1.0)
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# 处理NaN值
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result = np.nan_to_num(result, nan=0.0)
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return {
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'grid_values': result,
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'grid_lon': grid_lon,
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'grid_lat': grid_lat,
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'lon_range': lon_range,
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'lat_range': lat_range,
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}
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def optimize_edges(self, grid_data: Dict[str, Any],
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station_data: List[Dict[str, Any]]) -> Dict[str, Any]:
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"""
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优化栅格边缘（已在插值时处理，此方法保留用于向后兼容）
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Args:
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grid_data: 插值结果
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station_data: 站点数据
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Returns:
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优化后的栅格数据
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"""
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# 由于interpolate_rainfall已经包含了边缘优化和平滑处理
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# 这里不再重复处理，直接返回
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return grid_data
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def save_rainfall_grid_png(self, grid_data: Dict[str, Any], max_id: int) -> Optional[str]:
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"""
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将降雨栅格保存为PNG图片（背景透明）
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Args:
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grid_data: 栅格数据
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max_id: 最大ID
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Returns:
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PNG文件相对路径，失败返回None
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"""
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import numpy as np
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import matplotlib.pyplot as plt
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from matplotlib.colors import ListedColormap, BoundaryNorm
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from PIL import Image
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from config import settings
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try:
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grid_values = grid_data['grid_values']
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lon_range = grid_data['lon_range']
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lat_range = grid_data['lat_range']
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# 创建自定义颜色映射
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levels = self.rainfall_levels['levels']
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colors = self.rainfall_levels['colors']
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cmap = ListedColormap([
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tuple(c / 255.0 for c in color) for color in colors
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])
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norm = BoundaryNorm(levels, cmap.N)
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# 创建图形（设置dpi确保不拉伸）
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fig, ax = plt.subplots(1, 1, figsize=(10, 10), dpi=100)
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# 绘制栅格
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im = ax.pcolormesh(
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lon_range,
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lat_range,
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grid_values,
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cmap=cmap,
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norm=norm,
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shading='auto'
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)
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# 设置透明背景
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fig.patch.set_alpha(0)
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ax.patch.set_alpha(0)
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# 移除坐标轴
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ax.set_axis_off()
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# 调整布局，去除白边
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plt.tight_layout(pad=0)
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# 构建文件路径
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file_store_dir = settings.FILE_STORE_DIR
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grid_dir_template = settings.RAIN_STATION_GRID_DIR
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# 替换:id为实际的max_id
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grid_dir = grid_dir_template.replace(':id', str(max_id))
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# 完整路径
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full_dir = os.path.join(file_store_dir, grid_dir.lstrip('/'))
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# 创建目录
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os.makedirs(full_dir, exist_ok=True)
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# 保存PNG（使用PIL确保透明度）
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png_path = os.path.join(full_dir, 'grid.png')
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# 先保存到缓冲区
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buf = BytesIO()
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plt.savefig(buf, format='png', transparent=True, bbox_inches='tight', pad_inches=0)
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buf.seek(0)
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# 使用PIL打开并重新保存，确保透明度正确
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img = Image.open(buf)
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img.save(png_path, 'PNG')
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buf.close()
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plt.close(fig)
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# 返回相对路径（相对于FILE_STORE_DIR），统一使用正斜杠
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relative_path = os.path.join(grid_dir, 'grid.png').replace('\\', '/')
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saved_path = png_path.replace('\\', '/')
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self.logger.info(f"PNG图片已保存: {saved_path}")
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return relative_path
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except Exception as e:
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self.logger.error(f"保存PNG图片失败: {e}", exc_info=True)
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return None
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def store_to_redis(self, png_path: str, max_id: int,
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query_time, station_data: List[Dict[str, Any]]):
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"""
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将栅格信息存储到Redis
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Args:
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png_path: PNG文件相对路径
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max_id: 最大ID
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query_time: 查询时间（datetime对象或字符串）
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station_data: 站点数据
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"""
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from config import settings
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from app.utils.redis_helper import redis_helper
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try:
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redis_key = settings.REDIS_RAIN_STATION_GRID_KEY
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redis_identifier_key = settings.REDIS_RAIN_STATION_IDENTIFIER_KEY
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# 处理query_time，可能是datetime对象或字符串
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if isinstance(query_time, datetime):
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query_time_str = query_time.isoformat()
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else:
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query_time_str = str(query_time)
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# 构建辅助前端定位的信息
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grid_info = {
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'id': max_id,
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'png_path': png_path, # 相对路径
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'query_time': query_time_str,
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'resolution': self.grid_resolution, # 分辨率
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'station_count': len(station_data), # 站点数量
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# Cesium需要的定位信息
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'cesium_config': {
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'rectangle': {
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'west': self.xian_bounds['min_lon'],
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'south': self.xian_bounds['min_lat'],
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'east': self.xian_bounds['max_lon'],
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'north': self.xian_bounds['max_lat'],
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},
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# 图片尺寸（需要读取实际图片）
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'width': int((self.xian_bounds['max_lon'] - self.xian_bounds['min_lon']) / self.grid_resolution),
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'height': int((self.xian_bounds['max_lat'] - self.xian_bounds['min_lat']) / self.grid_resolution),
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}
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}
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# 存储到Redis
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redis_helper.set(redis_key, json.dumps(grid_info))
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redis_helper.set(redis_identifier_key, max_id)
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self.logger.info(f"栅格信息已存储到Redis，key: {redis_key}, id: {max_id}")
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except Exception as e:
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self.logger.error(f"存储到Redis失败: {e}", exc_info=True)
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# 创建全局实例
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rainfall_grid_service = RainfallGridService()
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