Table 6.50 — EEs for EAs with labels beginning with O
Attribute label Enumerant label Concept definition Figure(s) Code
OBJECT_ASPECT   The portion or aspect of an <OBJECT> in relation to the <TERRAIN>.    
  BODY Body.   1
  CUT <MATERIAL>s remaining after partial removal to depress the base of a <OBJECT> below the level of the surrounding <LAND>; cut.   2
  CUT_TRANSITION <<<CUT>>> transition.   3
  EMBANK <MATERIAL> used to elevate the base of an <OBJECT> above the level of the surrounding <TERRAIN>; embankment.   4
  EMBANK_OR_CUT_TRANSITION <<<EMBANK>>>s and/or <<<CUT>>>s transition <REGION>s.   5
  EMBANK_TRANSITION <<<EMBANK>>> transition.   6
  LEFT_CUT <<<CUT>>> located to the left side of the <DIRECTION> of travel.   7
  LEFT_CUT_TRANSITION <<<LEFT_CUT>>> transition.   8
  LEFT_EMBANK <<<EMBANK>>> located to the left side of the <DIRECTION> of travel or flow.   9
  LEFT_EMBANK_OR_CUT_TRANSITION <<<LEFT_EMBANK>>> and/or <<<LEFT_CUT>>> transition <REGION>s.   10
  LEFT_EMBANK_TRANSITION <<<LEFT_EMBANK>>> transition.   11
  LEFT_SHOULDER <<<SHOULDER>>> located to the left side of the <DIRECTION> of travel or flow.   12
  RIGHT_CUT <<<CUT>>> located to the right side of the <DIRECTION> of travel or flow.   13
  RIGHT_CUT_TRANSITION <<<RIGHT_CUT>>> transition.   14
  RIGHT_EMBANK <<<EMBANK>>> located to the right side of the <DIRECTION> of travel or flow.   15
  RIGHT_EMBANK_OR_CUT_TRANSITION <<<RIGHT_EMBANK>>> and/or <<<RIGHT_CUT>>> transition <REGION>s.   16
  RIGHT_EMBANK_TRANSITION <<<RIGHT_EMBANK>>> transition.   17
  RIGHT_SHOULDER <<<SHOULDER>>> located to the right side of the <DIRECTION> of travel or flow.   18
  SHOULDER Stopping strip along a travel way, typically gravel covered; shoulder.   19
OBJECT_CONFIGURATION   The type of configuration of an <OBJECT>.    
  DISPERSED The <OBJECT> consists of multiple <COMPONENT>s that are dispersed.   1
  DIVIDED_DIFFERENT_WIDTHS The <OBJECT> is divided into multiple <COMPONENT>s that have different <<WIDTH>>s.   2
  DIVIDED_SAME_WIDTH The <OBJECT> is divided into multiple <COMPONENT>s that have the same <<WIDTH>>.   3
  DOUBLE Double.   4
  INCLINED The <OBJECT> is inclined from either the horizontal or the vertical.   5
  JUXTAPOSITION The <OBJECT> consists of multiple <COMPONENT>s that are are juxtaposed with respect to one another.   6
  NON_DIVIDED The <OBJECT> is not divided into distinct, spatial separated <COMPONENT>s.   7
  SINGLE Single.   8
OBJECT_ORDINAL_RANK   The relative importance of an <OBJECT> as an ordinal rank.    
  FIRST Primary or first order.   1
  SECOND Secondary or second order.   2
  THIRD Tertiary or third order.   3
  FOURTH Quaternary or fourth order.   4
  FIFTH Quintary or fifth order.   5
OBJECT_ORIENTATION_WRT-
_VERTICAL
  The orientation of the usual axis of an <OBJECT> with respect to the vertical <DIRECTION>.    
  HORIZONTAL Perpendicular to the vertical; horizontal.   1
  INVERTED Inverted.   2
  LEANING Leaning.   3
  ON_SIDE On side.   4
  UPRIGHT Upright.   5
OBJECT_POLYGONAL_FACE_SHAPE   The shape of the polygon associated with a <NON_EMPTY_SET> of <POLYGONAL_FACE>s of an <OBJECT>.    
  EQUILATERAL_TRIANGLE Equilateral <<<TRIANGLE>>>.   1
  HEXAGON Hexagon.   2
  OCTAGON Octagon.   3
  PENTAGON Pentagon.   4
  RECTANGLE Rectangle.   5
  RIGHT_ISOSCELES_TRIANGLE Isosceles <<<RIGHT_TRIANGLE>>>.   6
  RIGHT_TRIANGLE Right <<<TRIANGLE>>>.   7
  SQUARE Square.   8
  TRIANGLE Triangle.   9
OBJECT_SET_TYPE   The type of an <OBJECT_SET>.    
  AERONAUTICAL Related to <AIRCRAFT>, <AERODROME>s, and other aeronautical activities.   1
  AERONAUTICAL_OBSTRUCTION Vertical obstructions to aeronautical navigation.   2
  AID_TO_NAVIGATION Related to <AID_TO_NAVIGATION>s.   3
  AIRSPACE Related to <AIRSPACE>s.   4
  ATS_ROUTE Related to <ATS_ROUTE>s.   5
  BEACH Related to <BEACH>s.   6
  BOUNDARY Related to political or geographic <BOUNDARY>s.   7
  COASTLINE Related to <COASTLINE>s, international <BOUNDARY>s, and major <MARINE_PORT>s.   8
  CULTURAL_LANDMARK Related to cultural landmarks.   9
  DATA_QUALITY Related to <DATA_QUALITY_BOUNDARY>s and <DATA_QUALITY_REGION>s.   10
  DATABASE_BOUNDARY Related to the <BOUNDARY>s of data libraries and databases.   11
  DEMARCATION Related to <LINE>s and <REGION>s of demarcation, which have been defined for administrative, political, military, or other purposes.   12
  ELEVATION Related to the relief or <<ELEVATION>> of the <TERRAIN>.   13
  FIXED_UNDERWATER_OBJECT Related to fixed <UNDERWATER_OBJECT>s.   14
  GROUND_OBSTACLE <OBJECT>s on, or in, the <TERRAIN> that act as <TERRAIN_OBSTACLE>s to the movement of <GROUND_VEHICLE>s.   15
  HYDRO Hydrographic <OBJECT>s, including characteristics of <WATERBODY_FLOOR>s, that are of significance to marine navigation.   16
  HYDRO_DANGER Offshore hydrographic <OBJECT>s, generally underwater, that constitute a danger to the movement of <VESSEL>s.   18
  HYDRO_LIMITS <LINE>s and <REGION>s of demarcation that have been defined for the purpose of controlling marine traffic; hydrographic limits.   19
  HYPSOGRAPHY Related to the <TERRAIN> that directly depict <<TERRAIN_ELEVATION>> information, including <CONTOUR>s and <SPOT_ELEVATION>s; hypsography.   20
  INDUSTRY Man-made and related to the commercial production and sale of goods and services; industry.   21
  INLAND_WATER Related to <INLAND_WATER> and associated <STRUCTURE>s.   22
  LAND_COVER Related to the <TERRAIN>, including agricultural and extraction activities, and related <SURFACE> characteristics; land cover.   23
  LAND_TRANSPORTATION_ROUTE Related to <LAND_TRANSPORTATION_ROUTE>s.   47
  MARINE_AID_TO_NAVIGATION Related to <MARINE_AID_TO_NAVIGATION>s.   17
  MARINE_ENVIRONMENT Environmental characteristics relating to <WATERBODY_CURRENT>s, <TIDE>s, and anomalies of significance to marine navigation; marine environment.   24
  MARINE_LIMIT <BOUNDARY>s of <WATERBODY>s of significance to marine operations; marine limit.   25
  MARINE_NAVIGATION Topographic and hydrographic <OBJECT>s including <SHORELINE>s, <ISLAND>s and <BOUNDARY>s of significance to marine navigation.   26
  MARINE_OBSTRUCTION Related to <MARINE_WRECK>s, offshore installations and obstructions of significance to marine navigation.   27
  MARINE_OVERVIEW Provide a generalized representation of a <MARINE_REGION>; marine overview.   28
  MARINE_SHORE Related to the <SHORE>, including <GLACIER>s, <TREE>s, <SWAMP>s and <MARSH>s of significance to marine navigation.   29
  MILITARY_AIRSPACE Vertical and lateral defined <AIRSPACE>s established for conducting military training and aerial refuelling.   30
  MILITARY_STRUCTURE Related to <STRUCTURE>s originally built for defensive purposes, although not necessarily still in use for such purposes; military structure.   31
  OCEAN_ENVIRONMENT Describing the physical characteristics of the <OCEAN> (and littoral) volume and floor; ocean environment.   32
  OCEAN_FLOOR Related to the <OCEAN_FLOOR> and <WATERBODY_FLOOR_TOPOGRAPHIC_CONFIGURATION>s.   33
  OVERVIEW Providing a generalized representation of a <REGION>; overview.   34
  PHYSIOGRAPHY Natural, exclusive of <INLAND_WATER>s, and comprising or laying upon the <TERRAIN> and its macro and micro relief; physiography.   35
  PLACE_NAME Identifying significant named <LOCATION>s; place name.   36
  PLANETARY_SCIENCE Related to the physical processes and phenomena occurring in a <PLANET> and its vicinity; planetary science.   37
  POLITICAL_ENTITY Identifying political entities and their <BOUNDARY>s.   38
  POPULATION Man-made and used to house, employ, administrate, provide medical care, and entertain the populace of a <REGION>; population.   39
  PORT_AND_HARBOUR Related to <MARINE_PORT>s and <HARBOUR>s, including their associated anchorage, docking and related cultural facilities.   40
  RAILWAY Related to <RAILWAY>s.   41
  ROAD Related to <ROAD>s.   42
  SHORE_STRUCTURE Hydrographic <OBJECT>s including <BREAKWATER>s, <PIER>s and <SHORE_PROTECTION_STRUCTURE>s of significance to marine navigation.   43
  TERMINAL_PROCEDURE Related to predetermined <AIRCRAFT> maneuvers in the vicinity of an <AERODROME> to orderly transition <AIRCRAFT> from take-off to the enroute phase of flight, or from the enroute to terminal phase of flight.   44
  TERRAIN_COMPOSITION Related to the composition of the <TERRAIN>.   45
  TERRAIN_CONFIGURATION Related to the slope or configuration of the <TERRAIN>.   46
  TILE_SET Defining a <NON_EMPTY_SET> of rectangular subdivisions of a <REGION>; tile set.   48
  TRACK_SWATH Related to <TRACK_SWATH>s.   49
  UNDERWATER_OBJECT Related to <UNDERWATER_OBJECT>s.   50
  UTILITY Related to the infrastructure of a <REGION>, and used to deliver utility services into the homes and businesses of the populace.
EXAMPLES     Electric power, natural gas, oil, water, sewerage, <TELEPHONE>, telecommunications.
  51
  VEGETATION Related to <VEGETATION>.   52
  WATERBODY_BATHYMETRY Related to relief or <<ELEVATION>> of a <WATERBODY_FLOOR>; waterbody bathymetry.   53
OBSCURANT_TYPE   The type of obscurant present in an <ATMOSPHERE>.    
  ADVECTION_FOG <FOG> caused by advection of moist <AIR> over a cold <PLANETARY_SURFACE>; advection fog.   1
  BLOWING_SNOW Snow lifted over the <PLANETARY_SURFACE> by <WIND> to a height of 2 metres or more; blowing snow.   2
  DESERT_HAZE Desert <<<HAZE>>>.   3
  DESERT_SUMMER Desert summer.   4
  DESERT_WINTER Desert winter.   5
  DUST_STORM An unusual, frequently severe, condition characterized by strong <WIND>s and <DUST_SUSPENSION> over an extensive <REGION>; dust storm.   6
  HAZE Suspension in the <ATMOSPHERE> of extremely small, dry <PARTICLE>s that are invisible to the naked eye but numerous enough to give the sky an opalescent appearance; haze.   7
  MARINE_HAZE <<<HAZE>>> consisting of salt <PARTICLE>s; marine haze.   8
  NONE_PRESENT No obscurant conditions are present; none present.   9
  RADIATION_FOG <FOG> produced over a <TRACT> when radiational cooling reduces the <<AIR_TEMPERATURE>> to or below its dew point; radiation fog.   10
  RURAL_HAZE Rural <<<HAZE>>>.   11
  SNOW Obscuration caused by the presence of <SNOW_PRECIPITATION> suspended in the <ATMOSPHERE>.   12
  TEMPERATE_SUMMER_DAY A condition present during the summer and dependent on the <<TEMPERATURE>> during the day; temperate summer day.   13
  TEMPERATE_SUMMER_NIGHT A condition present during the summer and dependent on the <<TEMPERATURE>> during the night; temperate summer night.   14
  TEMPERATE_WINTER A condition present during winter season and dependent on the <<TEMPERATURE>> at the time; temperate winter.   15
  TROPOSPHERIC <<<HAZE>>> in the <TROPOSPHERE>; tropospheric.   16
  URBAN_HAZE <<<HAZE>>> caused by or present in urban environments.   17
OBSERVATION_PLATFORM_TYPE   The type of an observation platform.    
  AIRCRAFT <AIRCRAFT>.   1
  BUOY <BUOY>.   2
  FIXED_WEATHER_STATION Fixed <WEATHER_STATION>.   3
  GEOPHYSICAL_SATELLITE Geophysical <ARTIFICIAL_SATELLITE>.   4
  HUMAN <HUMAN>.   5
  METEOROLOGIC_OBSERVATION_TOWER Meteorological observation <TOWER>.   6
  MOTOR_VEHICLE <MOTOR_VEHICLE>.   7
  VESSEL <VESSEL>.   8
OBSERVED_VISIBILITY_REPORT-
_TYPE
  The type of observed visibility that is reported.    
  MINIMUM Minimum observed <<VISIBILITY_DISTANCE>> during the reporting period.   1
  PRVL The visibility that is considered representative of visibility conditions at the station; the greatest distance that can be seen throughout at least half the horizon circle, not necessarily continuous; prevailing.   2
  PRVL_VAR_HIGH The maximum <<VISIBILITY_DISTANCE>> reported if the <<<PRVL>>> rapidly increases and decreases by 800 metres (approximately 0,5 miles) or more, during the time of observation, and the <<VISIBILITY_DISTANCE>> is less than 4 828 metres (approximately 3 miles); prevailing variable high [FMH1, 6.4.5].   3
  PRVL_VAR_LOW The minimum <<VISIBILITY_DISTANCE>> reported if the <<<PRVL>>> rapidly increases and decreases by 800 metres (approximately 0,5 miles) or more, during the time of observation, and the <<VISIBILITY_DISTANCE>> is less than 4 828 metres (approximately 3 miles); prevailing variable low [FMH1, 6.4.5].   4
  SECTOR The <<VISIBILITY_DISTANCE>> in a specific <DIRECTION> that represents at least a 45 arc degree sector of the horizon circle.   5
  TOWER The prevailing <<VISIBILITY_DISTANCE>> determined from airport traffic <CONTROL_TOWER> at stations that also report surface-level visibility.   6
  TOWER_PRVL_HIGH The maximum <<VISIBILITY_DISTANCE>> reported if the <<<TOWER>>> rapidly increases and decreases by 800 metres (approximately 0,5 miles) or more, during the time of observation and the <<VISIBILITY_DISTANCE>> is less than 4 828 metres (approximately 3 miles); tower prevailing high.   7
  TOWER_PRVL_LOW The minimum <<VISIBILITY_DISTANCE>> reported if the <<<TOWER>>> rapidly increases and decreases by 800 metres (approximately 0,5 miles) or more, during the time of observation and the <<VISIBILITY_DISTANCE>> is less than 4 828 metres (approximately 3 miles); tower prevailing low.   8
OCEAN_FLOOR_REGION_NAME_TYPE   The type of a named <REGION> of the <OCEAN_FLOOR> that has measurable relief or is delimited by relief.    
  ABYSSAL_HILLS A <WATERBODY_FLOOR_REGION> of small elevations in an <ABYSS>; abyssal hills.   1
  ABYSSAL_PLAIN A <<<PLAIN>>> in an <ABYSS>; abyssal plain.   2
  APRON A gently dipping <SURFACE>, underlain primarily by <SEDIMENT>, at the base of any steeper slope; apron.   3
  ARCHIPELAGIC_APRON A gentle slope with a generally smooth <SURFACE>, characteristically found around groups of <ISLAND>s or <<<SEAMOUNT>>>s; archipelagic apron.   4
  BANK An elevation over which the <<WATER_DEPTH>> is relatively shallow, but sufficient for safe navigation on the <WATERBODY_SURFACE>; bank.   5
  BANK_SET A <NON_EMPTY_SET> of <<<BANK>>>s in close proximity.   6
  BASIN <OCEAN_BASIN>.   7
  BORDERLAND A <WATERBODY_FLOOR_REGION> adjacent to a continent, normally occupied by or bordering a <<<CNTNTL_SHELF>>>, and sometimes emerging as <ISLAND>s that are irregular or blocky in plan or profile, with <<WATER_DEPTH>>s well in excess of those typical of a <<<CNTNTL_SHELF>>>; borderland.   8
  CALDERA A collapsed or partially-collapsed <<<SEAMOUNT>>>, commonly of annular shape; caldera.   9
  CANYON <WATERBODY_FLOOR_CANYON>.   10
  CANYON_SET A <NON_EMPTY_SET> of <<<CANYON>>>s, in close proximity.   11
  CAP A localized elevation, over which the <<WATER_DEPTH>> is relatively shallow, but sufficient for safe navigation on the <WATERBODY_SURFACE>; cap.   12
  CNTNTL_MARGIN The <<<ZONE>>>, generally consisting of a <<<CNTNTL_SHELF>>>, <<<CNTNTL_SLOPE>>> and <<<CNTNTL_RISE>>>, separating a continent from the deep <OCEAN_FLOOR> or <<<ABYSSAL_PLAIN>>>; continental margin. Occasionally a <<<TRENCH>>> may be present in place of a <<<CNTNTL_RISE>>>.   13
  CNTNTL_RISE A gentle slope rising from the depths of an <OCEAN> towards the foot of a <<<CNTNTL_SLOPE>>>; continental rise.   14
  CNTNTL_SHELF A <<<SHELF>>> adjacent to a continent.   15
  CNTNTL_SLOPE The deepening <OCEAN_FLOOR> out from the <<<SHELF_EDGE>>> of a <<<CNTNTL_SHELF>>> to the upper <BOUNDARY> of the <<<CNTNTL_RISE>>>, or the <LOCATION> where there is a general decrease in steepness; continental slope.   16
  DEEP An isolated localized deep <REGION> within the confines of a larger <WATERBODY_FLOOR_TOPOGRAPHIC_CONFIGURATION>, such as a <<<TROUGH>>>, <<<BASIN>>>, or <<<TRENCH>>>. Historically, it was limited to depths greater than 6 000 metres.   17
  ESCARPMENT An elongated, characteristically linear, steep slope separating horizontal or gently sloping sectors of the <OCEAN_FLOOR> in non-shelf <WATERBODY_FLOOR_REGION>s; escarpment. An escarpment is also called a scarp.   18
  FAN A relatively smooth, fan-like, depositional <WATERBODY_FLOOR_TOPOGRAPHIC_CONFIGURATION> normally sloping away from the outer termination of a <<<CANYON>>>, or <SYSTEM> of <<<CANYON>>>s; fan. A fan is also called a cone.   19
  FRACTURE_ZONE An extensive linear <<<ZONE>>> of irregular topography, mountainous or faulted, characterized by steep-sided or asymmetrical <<<RIDGE>>>s, clefts, <<<TROUGH>>>s, or <<<ESCARPMENT>>>s; fracture zone.   20
  GUYOT A <<<SEAMOUNT>>> having a comparatively smooth flat top; guyot. A guyot is also called a tablemount.   21
  GUYOT_SET A <NON_EMPTY_SET> of <<<GUYOT>>>s in close proximity.   22
  HILL An isolated elevation, smaller than a <<<SEAMOUNT>>>; hill.   23
  HILL_SET A <NON_EMPTY_SET> of <<<HILL>>>s in close proximity.   24
  HOLE A small local <TERRAIN_DEPRESSION>, often steep-sided; hole.   25
  KNOLL An elevation somewhat smaller than a <<<SEAMOUNT>>> and of rounded profile, characteristically isolated or as a cluster on the <OCEAN_FLOOR>; knoll.   26
  KNOLL_SET A <NON_EMPTY_SET> of <<<KNOLL>>>s, clustered, in close proximity.   27
  LEVEE A depositional natural embankment bordering a <<<CANYON>>>, <<<VALLEY>>>, or <<<SEA_CHANNEL>>>; levee.   28
  MEDIAN_VALLEY The axial <TERRAIN_DEPRESSION> of a <SYSTEM> of <MOUNTAIN>s forming part of a <<<MID_OCEANIC_RIDGE>>>; median valley.   29
  MID_OCEANIC_RIDGE The linked major mid-oceanic <SYSTEM>s of <MOUNTAIN>s, where such <SYSTEM>s are of global extent; mid-oceanic ridge.   30
  MOAT An annular <TERRAIN_DEPRESSION> that may not be continuous, located at the base of many isolated elevations (for example: <SEAMOUNT> and/or an <ISLAND>); moat.   31
  MOUNTAIN_SET A <NON_EMPTY_SET> of <MOUNTAIN>s, in close proximity.   32
  PASSAGE A narrow break in a <<<RIDGE>>> or a <<<RISE>>>; passage.   33
  PEAK A prominent elevation either pointed or of a very limited extent across the summit; peak.   34
  PINNACLE Any high tower or spire-shaped pillar of <ROCK> or <CORAL>, alone or cresting a summit; pinnacle.   35
  PLAIN An extensive, flat, gently sloping or nearly level <TERRAIN_PLAIN>.   36
  PLATEAU A <PLATEAU>, one or more sides of which drop off abruptly.   37
  PROMONTORY A major protrusion, resembling a <<<SPUR>>>, of the <<<CNTNTL_SLOPE>>> extending to the deep <OCEAN_FLOOR>; promontory. Characteristically, the crest deepens seaward.   38
  PROVINCE <WATERBODY_FLOOR_PROVINCE>.   39
  REEF <REEF>.   40
  REEF_SET A <NON_EMPTY_SET> of <<<REEF>>>s, in close proximity.   41
  RIDGE <WATERBODY_FLOOR_RIDGE>.
EXAMPLE     <<<MID_OCEANIC_RIDGE>>>.
  42
  RIDGE_SET A <NON_EMPTY_SET> of <<<RIDGE>>>s, in close proximity.   43
  RISE A broad elevation that rises gently and generally smoothly from the <OCEAN_FLOOR>, generally including the <<<MID_OCEANIC_RIDGE>>>s; rise.   44
  SADDLE A broad pass or col, resembling in shape a riding saddle, in a <<<RIDGE>>> or between contiguous elevations.   45
  SEA_CHANNEL A continuously sloping <TERRAIN_CHANNEL> found in <<<FAN>>>s or <<<ABYSSAL_PLAIN>>>s and customarily bordered by <<<LEVEE>>>s on one or both sides; sea channel.   47
  SEABIGHT A crescent-shaped indentation in the <OCEAN_FLOOR> formed by <WATER_CURRENT>s; seabight.   46
  SEAMOUNT <SEAMOUNT>.   48
  SEAMOUNT_CHAIN Several <<<SEAMOUNT>>>s in linear or arcuate alignment, with their bases clearly separated; seamount chain.   49
  SEAMOUNT_GROUP A distinct <NON_EMPTY_SET> of <SEAMOUNT>s, in close proximity to, but set off from, other <OCEAN_FLOOR> features; seamount group.   50
  SEAMOUNT_PROVINCE A <BATHYMETRIC_PROVINCE> of <<<SEAMOUNT>>>s.   51
  SEAMOUNT_SET A <NON_EMPTY_SET> of <<<SEAMOUNT>>>s, in close proximity.   52
  SHELF A <<<ZONE>>> adjacent to a continent (or around an <ISLAND>) and extending from the <LOW_WATER_LINE> to a depth at which there is usually a marked increase of slope towards the depths of the <OCEAN>; shelf.   53
  SHELF_EDGE The <LINE> along which there is marked increase of slope at the seaward margin of a <<<SHELF>>>; shelf edge.   54
  SHOAL An <UNDERWATER_HAZARD> with substantially less clearance than the surrounding <WATERBODY_FLOOR_REGION> and composed of unconsolidated <MATERIAL>; shoal.   55
  SHOAL_SET A <NON_EMPTY_SET> of <<<SHOAL>>>s, in close proximity.   56
  SILL A <BARRIER> of relatively shallow <<WATER_DEPTH>> restricting the movement of <WATER> between <<<BASIN>>>s; sill.   57
  SLOPE The deepening <OCEAN_FLOOR> out from a <<<SHELF_EDGE>>> to the upper limit of a <<<RISE>>>, or the <LOCATION> where there is a general decrease in steepness; slope.   58
  SOUND <MARINE_SOUND>.   59
  SPUR A subordinate elevation or <RIDGE> protruding from a larger <WATERBODY_FLOOR_TOPOGRAPHIC_CONFIGURATION> (for example: a <<<PLATEAU>>> and/or the foundation of an <ISLAND>); spur.   60
  TERRACE A relatively flat horizontal or gently inclined <WATERBODY_FLOOR_REGION>, sometimes long and narrow, which is bounded by a steeper ascending slope on one side and by a steeper descending slope on the opposite side; terrace.   61
  TRENCH <WATERBODY_FLOOR_TRENCH>.   62
  TROUGH A long <TERRAIN_DEPRESSION>, characteristically flat bottomed and steep-sided and normally shallower than a <<<TRENCH>>>; trough.   63
  VALLEY A relatively shallow, wide <TERRAIN_DEPRESSION>, the <WATERBODY_FLOOR> of which usually has a continuous gradient; valley. This term is generally not used for <WATERBODY_FLOOR_TOPOGRAPHIC_CONFIGURATION>s that have characteristics of <<<CANYON>>>s for a significant portion of their extent.   64
  ZONE An extensive linear <REGION> identifiable by a number of shared physiographic characteristics that are markedly in contrast with those in the surrounding <REGION>s; zone.   65
OCEAN_NAME   The name of an <OCEAN>.    
  ANTARCTIC Antarctic Ocean, or Southern Ocean, as defined in [LOS, 10]. The limits of the Antarctic Ocean are the parallel of 60°S to the north and the <COAST> of Antarctica, including the Antarctic Peninsula, to the south.   1
  ARCTIC Arctic Ocean as defined in [LOS, 9]. The Arctic Ocean is situated round the North Pole. Its southern limit generally follows the northern <COAST>s of North America, Greenland, and Eurasia.   2
  ATLANTIC <<<NORTH_ATLANTIC>>> plus <<<SOUTH_ATLANTIC>>> as defined in [LOS, 1 and 4].   3
  INDIAN Indian Ocean as defined in [LOS, 5]. The general limits of the Indian Ocean are the eastern <COAST> of Africa, the sourthen <COAST> of Asia, the western <COAST> of Australia, and the parallel of 60°S to the south.   4
  NORTH_ATLANTIC North <<<ATLANTIC>>> Ocean as defined in [LOS, 1]. The general limits of the North Atlantic Ocean are the eastern <COAST>s of South America and North America, the southern <COAST> of Greenland, the western <COAST>s of Europe and Africa, and the Equator.   5
  NORTH_PACIFIC North <<<PACIFIC>>> Ocean as defined in [LOS, 7]. The general limits of the North Pacific Ocean are the eastern <COAST> of Asia, the western <COAST> of North America, and the Equator.   6
  PACIFIC <<<NORTH_PACIFIC>>> plus <<<SOUTH_PACIFIC>>> as defined in [LOS, 7 and 8].   7
  SOUTH_ATLANTIC South <<<ATLANTIC>>> Ocean as defined in [LOS, 4]. The general limits of the South Atlantic Ocean are the eastern <COAST> of South America, the Equator, the western <COAST> of Africa, and the parallel of 60°S to the south.   8
  SOUTH_CHINA South China and Eastern Archipelagic Seas as defined in [LOS, 6]. The general limits of the South China and Eastern Archipelagic Seas are the eastern boundary of the Indian Ocean, the south-eastern <COAST> of Asia, and the western boundary of the Pacific Ocean.   9
  SOUTH_PACIFIC South <<<PACIFIC>>> Ocean as defined in [LOS, 8]. The general limits of the South Pacific Ocean are the eastern <COAST>s of Australia, Irian Jaya and Papua New Guinea, the Equator, the western <COAST> of South America, and the parallel of 60°S to the south.   10
OFFSHORE_PLATFORM_TYPE   The type of an offshore platform.    
  ACCOMMODATION Used primarily for eating, sleeping and recreation purposes; accommodation.   1
  ARTICULATED_LOADING A metal lattice <TOWER>, buoyant at one end and attached at the other by a universal joint to a concrete filled base on the <OCEAN_FLOOR>; articulated loading platform (ALP).   2
  ARTIFICIAL_ISLAND An artificial <STRUCTURE> usually constructed for the exploration or exploitation of marine resources, marine scientific research, or tidal observations; artificial island.   3
  FLOATING_PRODUCTION_VESSEL An offshore oil/gas <FACILITY> consisting of a moored tanker/barge by which the product is extracted, stored and exported; floating production vessel.   4
  MOORING_TOWER A tower-like <STRUCTURE> secured to the <OCEAN_FLOOR> and surmounted by a turntable to which <VESSEL>s moor; mooring tower.   5
  NAVIGATION_AID_SUPPORT A floating <MARINE_AID_TO_NAVIGATION> support <STRUCTURE> with control room, power and storage facilities, attached to the <OCEAN_FLOOR> by a flexible <PIPELINE> and cables.   6
  OBSERVATION Used primarily to observe, note, or record information about the surroundings or related events; observation.   7
  OBSERVATION_RESEARCH <<<OBSERVATION>>> and/or <<<RESEARCH>>>.   8
  OIL_DERRICK A temporary mobile <STRUCTURE>, either fixed or floating, used in the exploration stages of <PETROLEUM_FIELD>s, consisting of a combination of a derrick and <OIL_DRILLING_RIG>.   9
  PRODUCTION A permanent offshore <STRUCTURE> equipped to control the production and flow of oil or gas, excluding entirely submarine <STRUCTURE>s.   10
  RESEARCH Used primarily for scientific experimentation or research, including scholarly investigation or inquiry, intended to ultimately result in commercial products.   11
  SINGLE_ANCHOR_LEG_MOORING A rigid frame or tube with a buoyancy <DEVICE> at its upper end, secured at its lower end to a universal joint on a large steel or concrete base resting on the <OCEAN_FLOOR>, and at its upper end to a mooring <BUOY> by a <FLEXIBLE_RESTRAINT> (for example: a <CHAIN> or <WIRE>); single anchor leg mooring.   12
OIL_BARRIER_TYPE   The type of an <OIL_BARRIER>.    
  FLOATING A floating tube-shaped <STRUCTURE>, with a curtain (2 metres) hanging under it, below the <WATERBODY_SURFACE>, that acts as a <BARRIER> preventing the spread of oil.   1
  OIL_RETENTION_PIPE A <PIPE> with <APERTURE>s from which <AIR> blows under high pressure; oil retention pipe. When the bubbles of <AIR> reach the <WATERBODY_SURFACE> they form a <BARRIER> which prevents the spread of oil.   2
OMNIDIR_SHIP_NOISE_CONFIDENCE   A qualitative estimate of the degree of confidence in the <<OMNIDIR_SHIP_NOISE_SPCT_PWR_LVL>> at a specified <<FREQUENCY>>, based on the quantity and variability of the measurements.    
  LOW Low.   1
  MEDIUM Medium.   2
  HIGH High.   3
OPERATING_RESTRICTIONS_TYPE   The conditions during which the use of an <OBJECT> (for example: a <FACILITY> and/or an <AIRSPACE>) is restricted; operating restrictions type.    
  DAYTIME_ONLY Daytime operations; between sunrise and sunset only.   1
  NIGHT_TIME_ONLY Night-time operations; between sunset and sunrise only.   2
  NO_RESTRICTIONS No restrictions apply.   3
  PRONE_TO_FLOODING Prone to flooding that may restrict normal usage.   4
  PRONE_TO_ICE Prone to icy weather conditions that may restrict normal usage.   5
  PRONE_TO_SNOW Prone to snowy weather conditions that may restrict normal usage.   6
  SPECIAL_RESTRICTIONS Special restrictions apply.   7
OPERATING_TIME   The times during which the use of an <OBJECT> (for example: a <FACILITY> and/or an <AIRSPACE>) is unrestricted; operating time.    
  CONTINUOUS Continuous.   1
  DAYTIME Between sunrise and sunset; daytime.   2
  NIGHT_TIME Between sunset and sunrise; night-time.   3
  SUMMER_TIME_APRIL_OCTOBER Summer time; April through October.   4
  WINTER_TIME_NOVEMBER_MARCH Winter time; November through March.   5
OVERHEAD_OBSTRUCTION_TYPE   The type of an <OVERHEAD_OBSTRUCTION>.    
  BRIDGE_SUPERSTRUCTURE Limited by the design of the <BRIDGE>.   1
  HIGH_TENSION_POWERLINE Limited by a high-tension <POWER_TRANSMISSION_LINE>.   2
  RAILWAY_POWERLINE Limited by a <POWER_TRANSMISSION_LINE> for a <RAILWAY>.   3
  ROOF Limited by the design of the <ROOF>.   4
  VIADUCT_ARCH_CONSTRUCTION Limited by the construction of the arch overpass of a <VIADUCT>.   5
  VIADUCT_FRAME_CONSTRUCTION Limited by the construction of the frame overpass of a <VIADUCT>.   6