NOAA S-57 chart cell

Mississippi River, Atchafalaya River, and Gulf Intracoastal Waterway Alternate Route

US4LA1HI

Usage band
Approach · code 4
Current edition
1.1
Features
757
S-57 layers
49
Published
Jan 13, 2026
Manifest updated
Jun 22, 2026, 2:51 PM UTC

Coverage

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North
30.30000° N
South
30.00000° N
West
91.50000° W
East
91.20000° W
Center
30.15000° N, 91.35000° W
Bounds area
281 sq nm
Feature density
2.6983 / sq nm

Chart Statistics

20 largest layers shown

Average features per layer
15.4
Smallest layer
1
Largest layer
182
Area sq km
962
Features per sq km
0.7867
  1. COALNE Coastline 182
  2. SLCONS Shoreline construction 78
  3. RIVERS River 65
  4. DEPARE Depth area 58
  5. LNDRGN Land region 57
  6. DEPCNT Depth contour 30
  7. SEAARE Sea area 29
  8. PIPARE 23
  9. LNDARE Land area 20
  10. M_QUAL Data quality 20
  11. BRIDGE 16
  12. LAKARE 16
  13. OBSTRN Obstruction 16
  14. CBLOHD 12
  15. SOUNDG Sounding 12
  16. DISMAR 10
  17. VEGATN 10
  18. ROADWY 9
  19. BUAARE 8
  20. CBLARE 8

Nearby Chart Cells

Approach usage band

Current Edition Files

The NOAA ZIP archive is the upstream source for this chart cell; the other files are Open Ships generated derivatives for web and GIS use.

Editions

Edition Published Metadata
1.1 Jan 13, 2026 metadata.json