Recommendation Rationale Portrayal proposal Symbology Encoding

Copyright © 2014 Open Geospatial Consortium 15 6 Guidance for Specific NOTAMs Along with the general guidance for displaying graphical NOTAMs, the SAE-G10 document provides a set of recommendations for displaying specific types of NOTAMs. The specific NOTAMs addressed by the SAE comity are listed below: ฀ Runway closure, ฀ Displaced threshold runway for landing, ฀ Runway shortened, ฀ Taxiway closure, ฀ TFR, ฀ Changes to an instrument approach procedure IAP. The NOTAMs categories selected have been selected by the SAE Comity by researching which NOTAM categories resulted in the most frequent accidents and incidents. For those specific NOTAM, a deeper analysis will be performed to evaluate the feasibility of translating the associated recommendations into Symbology Encoding rules. For each NOTAM, the following items are presented: Content of the recommendation, Rationale behind the recommendation 5 , Portrayal proposed by SAE, Translation of recommendation into Symbology Encoding rule, issues encountered and proposed solution.

6.1 Runway Closure

6.1.1 Recommendation

The gNOTAM of a closed runway should indicate that the entire runway is closed, ensuring that users will be able to see that the runway is closed regardless of the scale of the display. One way to accomplish this is to superimpose X’s over the entire length of the closed runway rather than just at the end of the runway.

6.1.2 Rationale

If users can recognize that an entire runway is closed based upon the graphical depiction, then they are less likely to miss the closed runway even if they are viewing the runway on a scale that only shows part of the runway. 5 The recommendations and associated rationales are direct quotations from the SAE-G10 ARP6467. 16 Copyright © 2014 Open Geospatial Consortium

6.1.3 Portrayal proposal

Figure 1 - SAE-G10 proposal for Closed Runway gNOTAMs display

6.1.4 Symbology Encoding

The main requirement for symbology encoding for the Runway Closed NOTAM is to have Xs appear superimposed over the length of a closed runway. A Runway Closed DNOTAM generally contains a reference to the closed runway in the form of a TEMPDELTA timeslice. An intuitive approach to this problem would be to use a Point Symbolizer to style icons along the runway itself. Unfortunately, an AIXM 5.1 feature does not contain a set of points running through the center of the runway. The superimposition of X’s can instead be defined as a new rule using a PolygonSymbolizer with a specific fill pattern. The OGC filter for this rule requires the runway operational status to be closed, and relies on client support for WellKnownSymbol x. Copyright © 2014 Open Geospatial Consortium 17 For this rule we define the filter based on RunwayElementTimeSlice availabilityManoeuvringAreaAvailabilityoperationalStatus. The rule will apply when the value of this property is CLOSED. The rule can be applied on top of a base airport layout, but care must be taken that this rule is executed at a later point than the rules for the base runway. Rules inside the same SE file are executed from top to bottom. In other words: this rule needs to be defined below the base rule for runway elements. We chose an orange color for the Xs, to comply with the SAE-G10 guideline examples, and because it contrasts well with the base runway colors. The style overlays Xs over the entire runway, as was required by the SAE-G10 document. On top of that, we also visualize the outline of the runway as thick blue line. This was also inspired by the SAE-G10 guideline examples. See Figure 1 The blue outlines have the additional advantage of increased noticeability, even when the runway is visualized at a small scale. The Symbology Encoding rule is provided here: Rule Namerunway_closed_ruleName Description TitleRunway Closed NOTAM ruleTitle AbstractRule to render runways that are closed by superimposing their area with Xs and add a blue outline.Abstract Description ogc:Filter ogc:PropertyIsEqualTo ogc:PropertyName xmlns:ns0=http:www.aixm.aeroschema5.1 ns0:timeSlicens0:RunwayElementTimeSlicens0:availabilityns0:Manoeuvrin gAreaAvailabilityns0:operationalStatus ogc:PropertyName ogc:LiteralCLOSEDogc:Literal ogc:PropertyIsEqualTo ogc:Filter PolygonSymbolizer Geometry ogc:PropertyName xmlns:ns0=http:www.aixm.aeroschema5.1ns0:timeSlicens0:RunwayEl ementTimeSlice ogc:PropertyName 18 Copyright © 2014 Open Geospatial Consortium Geometry Fill GraphicFill Graphic Mark WellKnownNamexWellKnownName Stroke SvgParameter name=strokeF36E2BSvgParameter SvgParameter name=stroke-width1SvgParameter Stroke Mark Size16Size Graphic GraphicFill Fill PolygonSymbolizer LineSymbolizer Geometry ogc:PropertyName xmlns:ns0=http:www.aixm.aeroschema5.1ns0:timeSlicens0:RunwayEl ementTimeSlice ogc:PropertyName Geometry Stroke SvgParameter name=stroke-opacity ogc:Literal1.0ogc:Literal SvgParameter SvgParameter name=stroke-width ogc:Literal2ogc:Literal SvgParameter SvgParameter name=stroke ogc:Literal0000FFogc:Literal SvgParameter Stroke LineSymbolizer Rule The result of the proposed rule provides a result shown in Figure 2: Copyright © 2014 Open Geospatial Consortium 19 Figure 2 – Luciad Aviation Client visualization of Runway Closure NOTAM using SE 1.1 6.1.5 Problems encountered proposed solutions 6.1.5.1 Usage of WellKnownName