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# 假设使用SQLAlchemy进行数据库操作
from sqlalchemy import create_engine, Table, MetaData, select

engine = create_engine('sqlite:///rides.db')
metadata = MetaData(bind=engine)
rides = Table('rides', metadata, autoload=True)

# 优化前的查询
stmt = select([rides]).where(rides.c.status == 'completed')
result = engine.execute(stmt)

# 优化后的查询，添加索引
metadata.create_index(rides.c.status)
stmt = select([rides]).where(rides.c.status == 'completed')
result = engine.execute(stmt)

// 使用HTML5 Geolocation API结合第三方服务
function getLocation() {
    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(showPosition, showError);
    } else {
        console.log("Geolocation is not supported by this browser.");
    }
}

function showPosition(position) {
    let lat = position.coords.latitude;
    let lon = position.coords.longitude;
    // 结合第三方服务进行校准
    fetch(`https://api.example.com/geocode?lat=${lat}&lon=${lon}`)
        .then(response => response.json())
        .then(data => {
            console.log("Calibrated Position:", data);
        });
}

function showError(error) {
    switch(error.code) {
        case error.PERMISSION_DENIED:
            console.log("User denied the request for Geolocation.");
            break;
        case error.POSITION_UNAVAILABLE:
            console.log("Location information is unavailable.");
            break;
        case error.TIMEOUT:
            console.log("The request to get user location timed out.");
            break;
        case error.UNKNOWN_ERROR:
            console.log("An unknown error occurred.");
            break;
    }
}