On the Australian margin, submarine canyons have formed along all sides of the continent and are exposed to the potential influence of large-scale ocean currents, including the Leeuwin Current and the East Australian Current. Recognised in marine bioregional plans as potential biodiversity hotspots, many of these canyons sit within the new national network of Commonwealth Marine Reserves.
This GIS polygon layer contains 753 submarine canyons along the Australian continental margin and external territorie, mapped from a range of bathymetry datasets. The layer has attributes describing the canyon's geophysical characteristics. The definitions are as follows.
SHAPE_Leng: Perimeter (km)
SHAPE_Area: Planar area (km2)
centreli_L: Centreline length (km); total length of canyon/sub-canyons centreline(s)
MBG_Width: Minimum bounding rectangle width (km)
MBG_Length: Minimum bounding rectangle length (km)
MBG_Orient: Minimum bounding rectangle orientation
len_wid_ra: Length to width ratio; a measure of elongation; larger the value the more elongate the canyon
border_ind: Border index; a measure of geometric complexity; larger he value the more fractal the canyon
compactnes: a measure of compactness; larger the value the more compact the canyon (or the smaller its border)
no_branch: Number of sub-canyons
head_incis: Head incision (m); incision deph of canyon head
head_depth: Head depth (m); water depth of canyon head
foot_depth: Foot depth (m); water depth of canyon foot
depth_rang: Depth range (m); depth range between canyon head and foot
slope_mean: Slope mean; average slope gradients within canyon polygon
slope_std: Slope standard deviation; standard deviation of the slope gradients within canyon polygon
slope_rang: Slope range; range between maximum and minimum slope gradients within canyon polygon
surArea1: Surface area (km2); 3-D surface area of canyon
rugosity: Rugosity; roughness of canyon surface
volume: Volume (km3); 3-D volume enclosed by the canyon bottom and walls
head_x: X coordinate of canyon head; in Asia south Equidistant Conic projection
head_y: Y coordinate of canyon head; in Asia south Equidistant Conic projection
foot_x: X coordinate of canyon foot; in Asia south Equidistant Conic projection
foot_y: Y coordinate of canyon foot; in Asia south Equidistant Conic projection
h_f_dist: Head to foot distance (km); euclidian distance between canyon head and foot
h_f_slope: head to foot slope; slope gradient between canyon head and foot
dist_shelf: Distance to shelf (km); euclidian distance of canyon to shelf break; a distance of zero indicates that canyon touchs or intersects the shelf break or within the continental shelf
near_canyo: Nearest canyon (km); euclidian distance to the nearest canyon
dist_coast: Distance to coast (km); euclidian distance of canyon to Australian coast
focal_var: Focal variety; number of neighbouring canyons within a nominated proximity
inci_depth: Incision depth (m); averged depth of canyon area that incises into shelf break; slope-confined canyons have values of zero
inci_area: Incision area (km2) ; area of canyon area that incises into shelf break; slope-confined canyons have values of zero
slope15: Percentage of slope gradient greater than 15 degree; percentage of canyon area with slope gradients greater than 15 degree
sinuosity: a measure of sinuosity; larger the value the more sinuous the canyon
shelf_inci: Shelf incision; shlef-incising canyons have value of 1; slope-confined canyons have value of zero
dist_river: Distance to revier (km); euclidian distance to the mouth of the nearest permanent river
uncertain: Uncertainty; mapping uncertainty assigned to canyon; larger the value the more uncertain the mapping is
marine_reg: Marine region; the location of the canyon in one of the marine regions
canyon_nam: The name of canyon if known
map_region: Map region; the location of canyon in one of the map regions
Please refer to Marine Geology 357, 362-383 for details of mapping methods.
You can also purchase hard copies of Geoscience Australia data and other products at http://www.ga.gov.au/products-services/how-to-order-products/sales-centre.html
