Cruising Sailors Forum Archive

I did not change (read it again ) - mainly arguing number of pixels i.e. information.
In Response To: You just changed your argument ()

Resolution and size are related, and a chart plotter lacks both compared to paper. There has never been a resolution issue with chartplotters, if you are willing to look at a small enough bit of a chart at one time. A 4 pixel display can correctly render every bit of a raster chart. Would you be happy with it? Why not? For the same reasons, I am not overwhelmed by my chart plotter. It can render more of the chart than the 4 pixel display at full resolution, but still far less than all of it. If you think resolution is the whole answer to the problem, you should have no issue with using a cell phone as your main chartplotter - after all, it has greater resolution. My old iPhone 5s has more resolution (in pixels/inch and absolute number) than my brand new state of the art chartplotters. At a raw level the amount of information presented at one time might be thought of as the number of pixels. The resolution in pixels/inch or raw numbers for a printed page are between greater and much greater than the best chart plotters. Does that matter? I assert that it does. There have been several studies by NASA and the NTSB about how the human eye perceives things and picks up information which supports this idea.

Here is a concrete example. You are looking at a raster chart on your chartplotter and panning across several looking at a proposed route. You want to know the depth of a sounding. You must pan around and find the legend that tells you what units are being used as these change (feet, meters, fathoms) - this will be in the legend in the upper right corner usually, but not always - then pan back to where you were if you can find it. Or there is a notation "Warning see note B". Zoomed out to see the whole thing, the text is unreadable and note B cannot be found. Zoomed in you have to pan around and find it. On a paper chart, your eye darts instantly to the corners and locates the legend, and instantly back to where you were looking. This is done in fractions of a second without any thought, effort, or hand movement. These are trivial examples of many tens or hundreds of little things you perceive or should perceive when reading a chart, many of them done almost instantly and almost subconsciously. It has developed through our evolutionary background as hunters/hunted, and the charts were drawn with this knowledge, not with the idea that you would be looking at one small bit at a time. On vector charts some of these issues is solved but that is a whole different subject.

You can work around the drawbacks of electronic charting and navigate safely. On this we agree. You can work around the drawbacks of paper charts and navigate safely. This has a multi century history of proof.

What I object to is the notion that electronic charts are a perfect replacement for paper. They are not, they are a compromised replacement for paper, but with several unique advantages as well.

Having said all that, you may be surprised to hear me say that one of the primary reasons I just upgraded by chart plotters to Raymarine Lighthouse II version is specifically so I can display raster charts on the chart plotter. What I would like best though, is a holographic display of the paper chart projected in front of the binnacle in full size that with hand motions I can swipe to the next one or by touching an area automatically call up the larger scale version, or stitch together by blinking. Show me that, and I will concede your point #1.

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