何为AIO

AIO is a digital overlay which is displayed on ECDIS, it contains the limits of ADMIRALTY paper T&P Notices where the information is not in the underlying ENC. It also contains information about navigationally significant differences between ENCs and ADMIRALTY paper charts. It is provided free of charge to all AVCS customers. UKHO publishes a list of countries in AVCS, and whether they have confirmed that they publish temporary information in their ENCS. ADMIRALTY paper chart T&P NMs are included in AIO where the country does not include temporary information in their ENCs. ADMIRALTY only produce T&P NMs where there is paper chart coverage. A shaded ‘No overlay’ area is shown in AIO when there is no paper chart coverage at equivalent scale to ENC.

The overlay makes passage planning simpler by clearly showing where important Temporary or Preliminary changes may impact a voyage. It also draws attention to areas where differences between ENCs and paper charts may affect the passage plan.

摘自NP231

AIO是显示在ECDIS上的电子覆盖层，它包含了纸板临告预告上那些没有在其下层ENC上显示的内容。它也包含了电子海图和纸板海图之间的显著差异的信息。它对所有AVCS用户是免费提供的。UKHO列了一个某某国家有没有将其临时信息包含在其ENC中的清单。这些国家如果没有将临时信息包含在他们的电子海图里，那么纸板海图的临告预告信息会包含在AIO里面。ADMIRALTY仅仅会制作出有纸板海图覆盖区域的临告预告。当某一区域没有与电子海图同样比例尺的纸板海图时，AIO上会显示一片阴影区域，标有“No overlay”的字样。

电子覆盖层通过清晰地显示出可能影响航次的重要临告预告的变化使航行计划更加简单。它也能够着重区别出可能影响航行计划的电子海图与纸板海图的不同之处。

图例1：电子海图中，显示No overlay字样的区域，需要驾驶员格外关注此区域的航行警告。

图例2：我们常见的AIO显示形式，如图中的绿色和蓝色阴影区域。

图例3：ENC中包含临吿预告的情况。如图中右上角的浮标，就是一个临吿5236(T)/14，其被集成到ENC中。

图例4：纸版海图相应位置就需要我们手动改正。

图例5：还有另一种情况的AIO就是解释说明纸版海图与ENC之间的差异之处。如上图10513(EP)/19，该处在纸版海图BA937上有一个浮子，但是ENC上没有，这种情况，就需要驾驶员手动改正到电子海图上。