Update README.md

Author: DanielJDufour

Diff for: README.md

@@ -1,2 +1,9 @@
 # geotiff-stats
 Get Statistics from a GeoTIFF without Crashing Your Browser
+
+# usage
+```javascript
+import { getStats } from 'geotiff-stats';
+
+const stats = await getStats(image, { maximum: true, minimum: true, bufferSize: 10000 });
+```