Until recently surveyors had far more accurate positioning equipment at their disposal than did general shipping. To name a few examples of the then modern electronic equipment: Decca Survey Chains, Seafix-chains, Hifix 3-6 or the (bulky) SATNAV receivers from the 1970s. I came into contact with the first two examples when I first worked (with much pleasure) with Brian Apsey (see the interview with him in this issue).
The advantage which we surveyors had in positioning is nowadays minimised as GPS, and where possible DGPS, are common goods to the mariner and the recreational boater. These users expect that their charts will represent features with the same accuracy as they are able to determine (to ‘read’) their position now. A similar chain of reasoning can be held for the depth and full insonification. Mariners are not fully aware of these shortcomings in hydrographic surveys (for a lot of chart data is still based on pre-electronic era position and depth-measuring equipment) and have a blind trust in the charts. Mariners (and their shipowners) are in general traditional and adopt technological developments at a slower pace than the land-based industrial environment, see for example the use of computers on board ships which is only now becoming general practice. The blind trust in charts is nowadays with electronic charts and is emphasised by the aspect that ‘the computer tells it: so it is true’. This may very well result in reduced safety margins, which are the basis of safe navigation. However, navigating is no computer game where you can have several ‘lives’ before ‘game over’.
Surveyors engaged in nautical charting, dredging and working on dredging ships are using state-of-the-art systems. The dredging companies use these systems to guarantee that they have performed the job according to the requirements of the client and to ensure that they do not dredge too much (e.g. the channel is too wide or too deep) as strong competition forces to sharp tendering. This results on the one hand in a guaranteed depth/width, but it can also result in reduced safety margins as the extra margins used in the past in order to overcome uncertainties in equipment constraints are less.
The present computer technology makes it possible to run complex simulation programs for port approach and port manoeuvring on ordinairy PC equipment as a result, these operations can be simulated and trained on board as well as in the office. This is a very positive development to prepare and to train ships' crews, but it is also possible that crews can become overconfident thus reducing safety margins.
With approved positional accuracy, we know exactly where we are geographically. But, do we know where we are in relation to our environment? This aspect needs attention and improvement. For instance:

• As mentioned above: large areas of charts are either poorly surveyed or based on outdated surveys.
  
• If mariners arrive in areas where they use large-scale charts, other types of information could be very helpful: e.g. markings/numbers of dolphins, names of warehouses, opening hours of bridges, etc.