### 将经纬度坐标转换为大地坐标的Python代码 在地理信息系统中，将经纬度坐标转换为大地坐标是一项常见的需求。下面展示了一个简单的Python函数来完成这一任务。此过程涉及到WGS84椭球体参数的应用。 ```python import math def wgs84_to_ecef(lat, lon, alt): """ Convert WGS84 coordinates (latitude, longitude, altitude) to ECEF (Earth-Centered, Earth-Fixed) coordinates. Parameters: lat : float Latitude in degrees. lon : float Longitude in degrees. alt : float Altitude above the reference ellipsoid in meters. Returns: tuple of floats X, Y, Z coordinates in ECEF system. """ # Define semi-major axis and flattening factor for WGS84 Ellipsoid model a = 6378137.0 # Semi-major axis in meters f = 1 / 298.257223563 # Flattening b = a * (1 - f) # Calculate semi-minor axis using flattening e_squared = 1 - ((b ** 2) / (a ** 2)) # First eccentricity squared phi = math.radians(lat) lamda = math.radians(lon) N_phi = a / math.sqrt(1 - e_squared * math.sin(phi)**2) sin_phi = math.sin(phi) cos_phi = math.cos(phi) sin_lamda = math.sin(lamda) cos_lamda = math.cos(lamda) x = (N_phi + alt) * cos_phi * cos_lamda y = (N_phi + alt) * cos_phi * sin_lamda z = (((1 - e_squared) * N_phi) + alt) * sin_phi return x, y, z # Example usage with given latitude, longitude, and altitude values lat_example = 39.9042 # Beijing's approximate latitude lon_example = 116.4074 # Beijing's approximate longitude alt_example = 0 # Assuming sea level as an example ecef_coords = wgs84_to_ecef(lat_example, lon_example, alt_example) print(f"ECEF Coordinates: {ecef_coords}") ``` 上述代码实现了从WGS84标准下的经纬度坐标到ECEF（地心固定）坐标系统的转换[^1]。通过输入具体的纬度、经度和海拔高度值，可以获取对应的三维空间直角坐标(X,Y,Z)，这便是所谓的大地坐标形式之一。