GCP: Limit output to simplify lesson

landsat/search.json

@@ -1,5 +1,6 @@
 {
     "lat": 38.899313,
     "lon": -92.464562,
-    "landsat": "LANDSAT_8"
+    "landsat": "LANDSAT_8",
+    "limit": true
 }

landsat/search.py

@@ -8,6 +8,7 @@
 config=json.load(open("search.json"))
 lat,lon=config['lat'],config['lon']
 landsat=config['landsat']
+limit=config['limit']
 
 reader=csv.reader(sys.stdin)
 header=next(reader) # skip header
@@ -17,3 +18,4 @@
     north,south=float(NORTH_LAT),float(SOUTH_LAT)
     if SPACECRAFT_ID==landsat and north >= lat and south <= lat and west <= lon and east >= lon:
         print(BASE_URL) # output BASE_URL
+        limit and sys.exit(0) # limit results