oceam

Bathymetry

The measurement and study of ocean floor depths and topography.

Sounding

An individual numerical depth measurement plotted on a chart.

Isoline

A line on a map connecting points of equal numerical value.

Isobath

A depth contour line connecting points of equal water depth.

Contour Interval

The vertical difference in depth or value between adjacent contour lines.

Map Scale

The ratio of distance on a map to actual distance on Earth.

Large Scale

Map coverage of a small geographic area showing high detail.

Small Scale

Map coverage of a large geographic area showing low detail.

Continental Shelf

The shallow, gently sloping region extending from a coastline to the continental slope.

Continental Slope

The steeper region extending from the edge of the continental shelf down to the deep ocean floor.

Submarine Canyon

A steep-sided, V-shaped underwater valley cut into the shelf and slope.

Canyon Axis

The center line running along the deepest bottom path of a canyon.

Delta

A sediment deposit formed at a river mouth entering a body of water.

Terrigenous Sediment

River-derived sediment made of sand, silt, and clay washed off the land.

Carbonate Sediment

Sea floor deposits formed from the calcium carbonate structures of warm-water marine organisms.

Transect / Profile Line

A straight line drawn across a map used to construct a 2D cross-section graph.

Vertical Exaggeration

Graphically scaling the vertical axis larger than the horizontal axis to emphasize relief.

Fathom

A standard unit of ocean depth measurement equal to 6 feet or approximately 1.83 meters.

Interpolation

Estimating an unknown depth or value that falls between two known data points.

Extrapolation

Estimating an unknown value that lies outside the range of known sample points.

Depression Contour

A closed contour line with internal hachures indicating a basin or pit.

Concentric Closed Contours

Nested circular or oval lines representing a hill/peak or basin.

Gradient / Slope

The steepness of the sea floor, calculated as change in depth divided by horizontal distance.