What I didn’t realise when I wrote the recent post on the UKHO delaying the end of Admiralty paper charts was that there was a sting in the tail – they had wanted to drop raster electronic charts as well. That has also been delayed a few years to 2030 while they think about it.
This may be a detailed technical issue, but it matters a lot for navigators. Raster charts are the ones that look identical on screen to paper charts. They are really useful to us on Spring Fever as backups to our multi-layered, sometimes confusing and occasionally error-prone vector charts.
Paper and raster charts have the great advantage of simplicity and ease of use, and are especially good for route planning. You see everything in one image instead of having to explore through different layers to find detail, sometimes missing it
Another advantage is that electronic raster charts such as those published by VisitMyHarbour (VMH) keep the UKHO chartlets showing the age of the surveys on which the charts are based – in other words a reliability measure. That’s missing on the popular vector charts.
The issue for the UKHO is that paper and raster electronic charts both have to be extracted from a huge hydrographic database which is designed for producing vector charts. They say it is expensive to reprocess the data to publish paper or raster charts. The easy way out is to stop producing both. Let’s hope they can be pressured to change direction.
We may not know for a while: UKHO communications have inherited the reluctant style of the Ministry of Defence, from which the organisation emerged.
tide by tide 