Use outer edges for national PG grid

translate.go

@@ -29,8 +29,8 @@ var errNoProjection = newError("cornerPoints", "warning: unable to identify grid
 func (c *Composite) cornerPoints() (originTop, originLeft, edgeBottom, edgeRight float64, err error) {
 	// national grid (pg) values described in [4]
 	if c.Product == "PG" {
-		originTop, originLeft = 54.6547, 01.9178 // N, E
-		edgeBottom, edgeRight = 46.9894, 14.7218 // N, E
+		originTop, originLeft = 54.66218275, 1.900684377 // N, E
+		edgeBottom, edgeRight = 46.98044293, 14.73300934 // N, E
 		return
 	}
 

translate_test.go

@@ -52,11 +52,11 @@ func TestResolution(t *testing.T) {
 
 func TestTranslate(t *testing.T) {
 	nationalGridPG := [][]float64{
-		[]float64{54.6547, 01.9178, 0, 0},
-		[]float64{54.8110, 15.8706, 460, 0},
-		[]float64{51.0000, 09.0000, 230, 230},
-		[]float64{46.8695, 03.4921, 0, 460},
-		[]float64{46.9894, 14.7218, 460, 460},
+		[]float64{54.66218275, 1.900684377, 0, 0},
+		[]float64{54.81884457, 15.88724008, 460, 0},
+		[]float64{51.00000000, 09.00000000, 230, 230},
+		[]float64{46.86029310, 3.481345126, 0, 460},
+		[]float64{46.98044293, 14.73300934, 460, 460},
 	}
 
 	nationalGridHalf := [][]float64{