diff --git a/common/coords.go b/common/coords.go
index e29e480..2aa95f0 100644
--- a/common/coords.go
+++ b/common/coords.go
@@ -80,9 +80,13 @@ func DecodeStringFromBytes(key []byte) (pos int64, err error) {
 	return strconv.ParseInt(string(key), 10, 64)
 }
 
+func StringToBytes(key int64) []byte {
+	return []byte(strconv.FormatInt(key, 10))
+}
+
 // Encode a block pos to byte slice.
 func EncodeStringToBytes(key int64) ([]byte, error) {
-	return []byte(strconv.FormatInt(key, 10)), nil
+	return StringToBytes(key), nil
 }
 
 func ToBigEndian(key int64) []byte {
diff --git a/leveldb.go b/leveldb.go
index 7e655c3..ee1e08d 100644
--- a/leveldb.go
+++ b/leveldb.go
@@ -269,20 +269,17 @@ func (ldbs *LevelDBSession) plainSpatialQuery(first, second []byte, done chan st
 			for a.Y = c1.Y; a.Y <= c2.Y; a.Y++ {
 				b.Y = a.Y
 				from, to := order(common.CoordToPlain(a), common.CoordToPlain(b))
-				var encodedFrom []byte
-				if encodedFrom, err = common.EncodeStringToBytes(from); err != nil {
-					log.Printf("encoding key failed: %s", err)
-					return
-				}
-				it.Seek(encodedFrom)
-				for it.Valid() {
-					key := it.Key()
-					var decodedKey int64
-					if decodedKey, err = common.DecodeStringFromBytes(key); err != nil {
+				it.Seek(common.StringToBytes(from))
+				for ; it.Valid(); it.Next() {
+					var (
+						key = it.Key()
+						pos int64
+					)
+					if pos, err = common.DecodeStringFromBytes(key); err != nil {
 						log.Printf("decoding key failed: %s", err)
 						return
 					}
-					if decodedKey > to {
+					if pos > to {
 						break
 					}
 					select {
@@ -290,7 +287,6 @@ func (ldbs *LevelDBSession) plainSpatialQuery(first, second []byte, done chan st
 					case <-done:
 						return
 					}
-					it.Next()
 				}
 				if err = it.GetError(); err != nil {
 					log.Printf("iterating failed: %s", err)