updated downloader

internal/pkg/grib/cube.go

@@ -15,7 +15,7 @@ type cube struct {
 	file           *os.File
 }
 
-func openCube(path string) (*cube, error) {
+func openCube(path string, dc *DatasetConfig) (*cube, error) {
 	f, err := os.Open(path)
 	if err != nil {
 		return nil, err
@@ -27,14 +27,15 @@ func openCube(path string) (*cube, error) {
 		return nil, err
 	}
 
-	const (
-		nT   = 33  // 0-96 hours with step 3 hours (33 time steps)
-		nP   = 47  // 47 pressure levels matching tawhiri
-		nLat = 361
-		nLon = 720
-	)
-
-	return &cube{mm: mm, t: nT, p: nP, lat: nLat, lon: nLon, bytesPerVar: int64(nT * nP * nLat * nLon * 4), file: f}, nil
+	return &cube{
+		mm:          mm,
+		t:           dc.NT,
+		p:           dc.NP,
+		lat:         dc.NLat,
+		lon:         dc.NLon,
+		bytesPerVar: dc.SizePerVar(),
+		file:        f,
+	}, nil
 }
 
 func (c *cube) val(varIdx, ti, pi, y, x int) float32 {