Update README.md

README.md

@@ -53,4 +53,4 @@ The images are bounded be the following coordinates ([-180.0, -85.0511287798066,
 notice that the dataset does not contain the north and south pole.
 The dataset contains 3 zoom levels (5,6,7) at (1024, 4096, 16384) tiles respectively so in total 21541 images are avaliable.
 The resolution is 512x512, each image has a metadata which contains the coordinates of the image footprint i.e the coordinates of the corners it also 
-contains the square area in km that the image covers. We use EPSG:4326 projection. 
+contains the square area in km that the image covers. We use the EPSG:4326 coordinate reference system.