Enhance Earth interaction and bump version to 0.21.0

backend/app/api/v1/visualization.py

@@ -5,7 +5,7 @@ Returns GeoJSON format compatible with Three.js, CesiumJS, and Unreal Cesium.
 """
 
 from datetime import datetime
-from fastapi import APIRouter, HTTPException, Depends
+from fastapi import APIRouter, HTTPException, Depends, Query
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select, func
 from typing import List, Dict, Any, Optional
@@ -400,7 +400,11 @@ async def get_all_geojson(db: AsyncSession = Depends(get_db)):
 
 @router.get("/geo/satellites")
 async def get_satellites_geojson(
-    limit: int = 10000,
+    limit: Optional[int] = Query(
+        None,
+        ge=1,
+        description="Maximum number of satellites to return. Omit for no limit.",
+    ),
     db: AsyncSession = Depends(get_db),
 ):
     """获取卫星 TLE GeoJSON 数据"""
@@ -409,8 +413,9 @@ async def get_satellites_geojson(
         .where(CollectedData.source == "celestrak_tle")
         .where(CollectedData.name != "Unknown")
         .order_by(CollectedData.id.desc())
-        .limit(limit)
     )
+    if limit is not None:
+        stmt = stmt.limit(limit)
     result = await db.execute(stmt)
     records = result.scalars().all()