diff --git a/src/pg/sql/45_observatory_mvt.sql b/src/pg/sql/45_observatory_mvt.sql
index 861fd78..b94c4f4 100644
--- a/src/pg/sql/45_observatory_mvt.sql
+++ b/src/pg/sql/45_observatory_mvt.sql
@@ -393,7 +393,7 @@ BEGIN
     SELECT  mvtgeom,
             (select row_to_json(_) from (select id, %13$s %3$s, area_ratio) as _) as mvtdata
           FROM (
-      SELECT ST_AsMVTGeom(the_geom, $1, $2, $3, $4) AS mvtgeom, %12$s as id, %10$s %11$s, area_ratio FROM (
+      SELECT ST_AsMVTGeom(ST_Transform(the_geom, 3857), $1, $2, $3, $4) AS mvtgeom, %12$s as id, %10$s %11$s, area_ratio FROM (
         SELECT  %1$s the_geom, %12$s, %2$s %3$s,
                 CASE  WHEN ST_Within($5, %1$s)
                         THEN ST_Area($5) / Nullif(ST_Area(%1$s), 0)