Table 6.12 -- EDCS Attributes whose label begins with I
| Label | Definition | Attribute value type | EQ label | Related concepts | Code |
| IALA_NAVAID_TYPE | The type of conformity of a navigational aid to the IALA system of navigational aids. | ENUMERATION | 396 | ||
| ICAO_AIRSPACE_CLASS | The ICAO designated airspace classification. | ENUMERATION | 397 | ||
| ICAO_LOCATION_INDICATOR | The ICAO four-letter location indicator for geographical locations throughout the world; coded as specified by I7910. | STRING | EA HOST_COUNTRY_LOC_IDENTIFIER | 398 | |
| ICE_COVERED | Indicates that the water surface is covered with ice. | LOGICAL | 399 | ||
| ICE_DRAFT_RMS | The RMS ice draft within a nominal 111,120 kilometres (60 nautical miles) square cell of the ocean. | REAL | LENGTH | 400 | |
| ICE_FACTOR | The value of the maximum variation in the vertical clearance of an overhead cable due to an accumulation of ice. | REAL | LENGTH | 401 | |
| ICE_KEEL_COUNT | The number of ice keels within a nominal 111,120 kilometres (60 nautical miles) square cell of the ocean. | COUNT | 402 | ||
| ICE_LAYER_THICKNESS | The thickness of the layer of ice that covers a body of water. | REAL | LENGTH | 403 | |
| ICE_TYPE | The kind of ice. | ENUMERATION | 404 | ||
| ICE_X_INDEX | The X-cell position within a gridded field of polar ocean statistics. The X-axis is parallel to the line of 0 arc degrees geodetic longitude with a nominal square cell size of 111 120 metres (60 nautical miles); the origin is at the pole. | INDEX | 405 | ||
| ICE_Y_INDEX | The Y-cell position within a gridded field of polar ocean statistics. The Y-axis is parallel to the line of 90 arc degrees geodetic longitude with a nominal square cell size of 111 120 metres (60 nautical miles); the origin is at the pole. | INDEX | 406 | ||
| IGNITION_FLASH | The fraction of maximum transient illumination induced by ignition of a combustible material, e.g., a munitions launch. The following interpretations may be applied: 1/4: Small, 2/4: Medium, 3/4: Large, 4/4: Maximum. | REAL | PURE_NUMBER | 407 | |
| ILLUMINANCE | The quantity of visible light defined as radiation per unit time (flux) per unit area, as processed by the normal human eye, i.e., light level or illuminance. | REAL | RADIANT_ENERGY_FLUENCE | 408 | |
| IMO_ADOPTED | Indicates that the object has been adopted by the IMO. | LOGICAL | 409 | ||
| INCIDENT_AZANG_GEODETIC | The angle in the horizontal plane, measured in a clockwise direction from above, from planetary geodetic north to the projection of the incident vector in the horizontal plane. | REAL | PLANE_ANGLE | 410 | |
| INCIDENT_AZANG_LOCAL_NORMAL | The angle in the plane perpendicular to the local normal, generally the local x-y plane which is perpendicular to the local z-axis, measured counter-clockwise from the azimuth reference vector, normally the local x-axis, to the projection of the incident vector onto that plane. This attribute is generally used as a qualifier for other attributes, e.g., reflectivity as a function of incident angle. | REAL | PLANE_ANGLE | 411 | |
| INCIDENT_ELANG_HORIZONTAL | The angle in the vertical plane, measured from the horizontal plane, to the incident vector. | REAL | PLANE_ANGLE | 412 | |
| INCIDENT_ELANG_LOCAL_NORMAL | The angle measured from the plane perpendicular to the normal vector to the incident vector and defined positive if the incident vector is in the same hemisphere as the normal vector and negative otherwise. This attribute is generally used as a qualifier for other attributes, e.g., reflectivity as a function of incident angle. | REAL | PLANE_ANGLE | 413 | |
| INFRARED_HEAT_FLUX | The rate of flow of heat to a system due to infrared radiation. | REAL | IRRADIANCE | 414 | |
| INITIAL_LIGHT_SECTOR_ANGLE | Initial horizontal angular limit of light visibility. Limits of sectors and arcs of visibility are arranged clockwise and are given from seaward toward the light. | REAL | PLANE_ANGLE | EA TERMINAL_LIGHT_SECTOR_ANGLE | 415 |
| INLAND_WATER_OBSTRUCTION | Indicates that the object is an inland water body is an obstruction to vessel movement. | LOGICAL | 416 | ||
| INTERCHANGE_TRAVERSABILITY | The traversability provided by a four-way road interchange between adjacent road entry segments. Each entry road segment necessarily connects to an opposing exiting segment (two pairs are thus formed) and optionally to either of the adjacent left or right road entry segments. The first entry segment is that entering the interchange in the direction of the associated bridge span; the remaining three entry segments are ordered in a counter-clockwise direction with the third entry serving as the exit for the first entry, and similarly the fourth for the second. | ENUMERATION | 417 | ||
| INTEREST_TYPE | The reason an object is of interest. | ENUMERATION | 418 | ||
| INTERIOR_FLOW_SPEED | The speed of any internal convective flow within an object. | REAL | VELOCITY | 419 | |
| INTERIOR_LIGHTING_INTENSITY | The fraction of maximum intensity of general internal lighting. | REAL | PURE_NUMBER | 420 | |
| INTERIOR_TEMPERATURE | The temperature of the interior of the material or object. | REAL | THERMO_TEMPERATURE | 421 | |
| IONSCINT_ALONG_AXIS | The scintillation irregularity strength along the local geomagnetic axis. Scintillation is the distortion of the propagation of electromagnetic radiation due to irregularities in the medium through which the radiation is moving. | REAL | PURE_NUMBER | 422 | |
| IONSCINT_DRIFT_X_SPEED | The speed of the scintillation density irregularities along the X axis. | REAL | VELOCITY | 423 | |
| IONSCINT_DRIFT_Y_SPEED | The speed of the scintillation density irregularities along the Y axis. | REAL | VELOCITY | 424 | |
| IONSCINT_DRIFT_Z_SPEED | The speed of the scintillation density irregularities along the Z axis. | REAL | VELOCITY | 425 | |
| IONSCINT_FREQUENCY_SLOPE | The rate of change (slope) of the scintillation irregularity strength with respect to frequency. Scintillation is the distortion of the propagation of electromagnetic radiation due to irregularities in the medium through which the radiation is moving. | REAL | LENGTH | 426 | |
| IONSCINT_IRREG_STRENGTH | The height-integrated scintillation irregularity strength (CkL); this corresponds to the total integration of scintillation effects across all frequencies. Scintillation is the distortion of the propagation of electromagnetic radiation due to irregularities in the medium through which the radiation is moving. | REAL | PURE_NUMBER | 427 | |
| IONSCINT_MAXIMUM_SIZE | The upper limit on the size of the scintillation density irregularities. Scintillation is the distortion of the propagation of electromagnetic radiation due to irregularities in the medium through which the radiation is moving. | REAL | LENGTH | 428 | |
| IONSCINT_PERP_TO_AXIS | The scintillation irregularity strength perpendicular to the local geomagnetic axis. Scintillation is the distortion of the propagation of electromagnetic radiation due to irregularities in the medium through which the radiation is moving. | REAL | PURE_NUMBER | 429 | |
| IONSCINT_PHASE_ALTITUDE | The altitude of the equivalent phase screen. | REAL | LENGTH | 430 | |
| IONSCINT_STRUCTURE_ANGLE | The angle between the scintillation irregularities and the local geomagnetic field line. If zero, all ionospheric plasma density irregularities are aligned along the local magnetic field line. | REAL | PLANE_ANGLE | 431 | |
| IRRIGATION_TYPE | The method used to supply crops with water. | ENUMERATION | 432 | ||
| ISO_COUNTRY_IDENTIFICATION | The two character country identification code as designated in ISO 3166-1:1997, identifying the country and its subdivision. | STRING | 433 | ||
| ISOBARIC_SURFACE_LEVEL | The altitude, relative to MSL, of a standard isobaric surface in units proportional to the potential energy of unit mass (geopotential) at this altitude. | REAL | GEOPOTENTIAL_ENERGY_LENGTH | EA GEOPOTENTIAL_ALTITUDE | 434 |
| ISOLATED_COMMUNICATION_LINE | Indicates that the communication line is in the open (isolated) as opposed to being in the midst of other objects (not isolated). | LOGICAL | 435 |