diff --git a/src/stores.py b/src/stores.py
index f6d921039ac25804a17653bf588f56e422bf57da..0000b7e163f48f5116ef9b4613aca460b68bc697 100644
--- a/src/stores.py
+++ b/src/stores.py
@@ -404,8 +404,9 @@ class Coveragestore(object):
         return self.backend.GetProjection()
 
     def get_proj4(self):
-        # TODO compute this.
-        return "+proj=longlat +datum=WGS84 +no_defs"
+        proj = osr.SpatialReference()
+        proj.ImportFromWkt(self.get_projection())
+        return proj.ExportToProj4()
 
     def nbbands(self):
         return self.backend.RasterCount