Update README.md

README.md

@@ -93,7 +93,9 @@ The annotations are stored in JSON format. Each image is annotated with "image_w
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 ## Meta data
-The meta data of GPS coordinates and image acquisition time are also provided. The meta data is stored in a JSON file. (We will upload it as soon as possible.)
+The meta data of GPS coordinates and image acquisition time are also provided. The meta data is stored in a JSON file. Image names are keys and values are the tiles we used in each images. 
+Please refer more details in [get_google_maps_image](https://github.com/bjzhb666/get_google_maps_image). 
+We can use the meta data to calculate the center of a picture and the code will be released in [Code (We will release all the codes as soon as possible)](https://github.com/OpenSatMap/OpenSatMap-offical).
 
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 {