Update README.md

HuangLiPang · web-flow · commit 50c5a1122453 · 2018-08-16T14:38:45.000+08:00
diff --git a/README.md b/README.md
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 # PM2.5-IDW-Map
 
-An PM2.5 Inverse Distance Weighting (IDW) map using [Leaflet](https://leafletjs.com/)(v0.7.7).
+An PM2.5 Inverse Distance Weighting (IDW) map using [Leaflet](https://leafletjs.com/) (v0.7.7).
 
 PM2.5 data source
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