: Public <<DataType>> Class
Created: 20/03/2012 12:01:19
Modified: 26/08/2012 08:44:29
Project:
Advanced:
An aggregation of horizontal visibility conditions typically reported together at an aerodrome, including the prevailing visibility and minimum visibility. 
Attribute
Public PrevailingVisibility
  prevailingVisibility

Details:
Notes: The reported prevailing horizontal visibility at the surface that is representative of the aerodrome.<br /></p><p><br /></p><p>The greatest visibility value, observed in accordance with the definition of "visibility¨, which is reached within at least half the horizon circle or within at least half of the surface of the aerodrome. These areas could comprise contiguous or non-contiguous sectors.<br /></p><p><br /></p><p>Note: This value may be assessed by human observation and/or instrumented systems. When instruments are installed, they are<br /></p><p>used to obtain the best estimate of the prevailing visibility.<br /></p><p><br /></p><p>Annex 3:<br /></p><p>Section 4.2.4.4b<br /></p>
Public Visibility_Aero
  minimumVisibility

Details:
Notes: Section 4.2.4.4a:<br /></p><p>"When the visibility is not the same in different directions and<br /></p><p>a) when the lowest visibility is different from the prevailing visibility, and <br /></p><p>  1) less than 1 500 m or <br /></p><p>  2) less than 50 percent of the prevailing visibility and less than 5 000 m; the lowest visibility observed should also be reported and,when possible, its general direction in relation to the aerodrome reference point indicated by reference to one of the<br /></p><p>eight points of the compass. If the lowest visibility is observed in more than one direction, then the most<br /></p><p>operationally significant direction should be reported; and<br /></p><p>b) when the visibility is fluctuating rapidly, and the prevailing visibility cannot be determined, only the lowest visibility<br /></p><p>should be reported, with no indication of direction."<br /></p>
Public Angle
  minimumVisibilityDirection

Details:
Notes: The direction of the minimum visibility relative to the reporting station.  This is optional in cases where minimum visibility is reported but the visibility is fluctuating rapidly.  Minimum visibility is reported in cardinal and inter-cardinal directions (N, NE, E, SE, S, SW, W, and NW)
Element Source Role Target Role
«Type» MeteorologicalAerodromeObservationRecord
Class   		Name:  
  		Name: visibility
 
Details:
Not reported when ceiling and visibility OK
Constraint Type Status
if( self.minimumVisibility NOT NULL ) minimumVisibilityDirection NOT NULL Invariant Approved
Details:
Minimum visibility and the direction must be reported together