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Maro Reef: Maps and Imagery
Maro
Reef map:
View a full-resolution version (227 KB).
Maro
Reef IKONOS image:
View the 13m-resolution version (1,359 KB).
Download the 8m-resolution version (2,424 KB zip file).
Maro
Reef bathymetry image:
View the 13m-resolution version (1,030 KB) with depth scale.
Download the 4-meter resolution geotiff (23,923 KB zip file). See the Digital number (DN) to Classification matchup for NWHI bathymetry files.
See the legend PDF to view the colorbars for the depth scales and the legends for habitat cover and detailed class.
Image
of Maro Reef habitat cover:
View the 13m-resolution version (1,964 KB) with legend.
Download the 4-meter resolution geotiff (3,411 KB zip file). See the Digital number (DN) to Classification matchup for NWHI habitat cover files.
See the legend PDF to view the colorbars for the depth scales and the legends for habitat cover and detailed class.
Maro
Reef detailed habitat image:
View the 13m-resolution version (1,713 KB) with legend.
Download the 4-meter resolution geotiff (3,836 KB zip file). See the Digital number (DN) to Classification matchup for NWHI detailed classification files.
See the legend PDF to view the colorbars for the depth scales and the legends for habitat cover and detailed class.
Maro Reef: Shapefiles
Click on the links below to download shapefiles which correspond to the French Frigate Shoals detailed habitat class and aggregated cover imagery. Each zipped shapefile consists of 6 separate files, with the same root name and .dbf, .prj, .sbn, .sbx, .shp, and .shx extensions.
Maro
Reef: Detailed habitat shapefile (100 MB)
Maro
Reef: Habitat cover shapefile (89 MB)
Click here to download a .ZIP file which contains the Arc and PCI legend files (.avl and .rst extension) for the NWHI maps. When added to your Arc or PCI project, these files will cause the vector colors to match the geotiffs.
Maro Reef: Description and History
Approximately 1200 km WNW of Kauai and 1000 km ESE of Midway lies Maro Reef at longitude 170 degrees 35 minutes W and latitude 25 degrees 22 minutes N. Maro Reef is a shallow-water reef ecosystem approximately 50 km long and 30 km wide and covering an estimated 1,856 sq. km It is one of the most ecologically rich locales in the Northwestern Hawaiian Islands. Only one small rock outcrop of this former island reportedly extends above the ocean surface, and then only at very low tide. Much of the reef habitat at Maro Reef is composed of a series of intricate reticulated (forming a network) reef crests and surrounding lagoons. Many areas of Maro Reef appear quite similar to Pearl and Hermes, including a few small micro atolls. This reef may have the most coral cover in the Northwestern Hawaiian Islands. The shallow reef areas consist of numerous patch reefs, submerged pinnacles and elongate reticulate reef complexes. Channels of deep water with highly irregular bottom topography lie between the shallow reef structures.
Maro Reef is essentially an open atoll that lacks the typical protective outer ring of islands and ocean reefs that enclose a typical atoll lagoon. The outermost reefs of Maro Reef function as a broken reef crest complex, and absorb the energy of ocean swells that travel toward the inner lagoon region. The innermost area of the reef complex lies within boundaries of reticulated reefs and aggregated patch reefs and has all the characteristics of a true lagoon, with little or no influence from large ocean swell.
In 1928, a mapping survey was conducted at Maro Reef. That survey described the placement of a tower on an emergent shallow-water coral reef platform. A survey in 2001 failed to locate the 1928 tower, but it did show the possible remnants. Coral at Maro Reef may grow fast enough to disguise a human-made feature.