Raster or Vector charts or BOTH?

[CaptTom]

First of all, I'm totally on board with moving to vector charts. It's the way of the future, much more versatile, and ideally you only want to have one format to maintain.

My problem is with the current implementation.

Originally Posted by Dockhead

...And BTW, not all vector charts are as badly made as the ones you describe. The Navionics ones are mostly pretty decent (although the quality varies according to the area), and the Platinum ones solve the problem you mention about land features, by overlaying Google Earth images. Albeit at a price!

I'm only talking about US Government NOAA charts, although I've seen the same thing with CHS charts.

I do not want to have to buy additional charts from for-profit third parties to get the data which is already on the gov't raster charts.

That also flies in the face of the "one format to maintain" benefit of vector.

Originally Posted by conachair

...Seems I was pretty close, the data is exactly the same - just the presentation is different...

No it isn't. I've personally seen thousands of instances where the data is missing or flat out wrong.

Originally Posted by conachair

From using computers and CAD for decades I've no qualms whatsoever to using vector start to finish on a computer, completely comfortable with turning off or on layers which are of no interest to whatever is being done at the time...

Me too. Vector is a much better technology.

However, as I understand it, there are no different scale layers embedded in the vector charts. Just classes of entries. It's up to the software to decide. So I can choose to, say, not show unlighted buoys at some scale, but I can't choose to leave off the names of small islands, but retain the large ones.

This isn't a CADD drawing, where you might want to show all plumbing, but no electrical. As you scale in and out, different items of the same type become more and less important.

Originally Posted by conachair

Overall I think you're being far too hard on vector, the data is there, you need to learn a different way to work...

I have nothing against the vector format.

Getting some low-bid contractor to digitize everything to vector charts once, with no real understanding of how it'll be used, with faulty quality control, then making no effort to recover lost data or fix incorrect data before dropping support for raster charts is not the way to do this.

Originally Posted by transmitterdan

I think very little data is “stripped out” of nationally produced vector charts.

Then you haven't seen the charts I have seen.

[bdbcat]

ranger42c...


re:
"Ummm.... small point... There was a programmer somewhere behind that computer decision-making..."


A bit more here, especially focused on the commercial navigation world. For vector ENCs, the rules for what to display, and how to display it, are defined in the IHO S52 standards. This includes factors such as at what zoom level to hide the item, where to place the associated text, what size text to use, what layer it is rendered on, etc. Defining these parameters for each object on the chart is part of the digitizing process, and also involves a human cartographer. Mistakes can be made...

The goal of this rule set is to make ENCs look and act the same no matter what vendor of ECS or ECDIS is used. This helps in operator training. A licensed ship crew can more easily and safely move from one ship to another.


OpenCPN follows this rule set.


One of the more difficult problems is de-cluttering of text. The standards do not give much guidance on prioritization of the navigational usefulness of most text items. It is up to the implementation to attempt this prioritization. Opinions will differ on the dynamic choices made by the programmer at runtime.



Hope this helps.
Dave

[conachair]

Originally Posted by CaptTom

No it isn't. I've personally seen thousands of instances where the data is missing or flat out wrong.

Any examples? WHere? From who?

Ta

[ranger58sb]

Originally Posted by bdbcat

ranger42c...

re:
"Ummm.... small point... There was a programmer somewhere behind that computer decision-making..."

A bit more here, especially focused on the commercial navigation world. For vector ENCs, the rules for what to display, and how to display it, are defined in the IHO S52 standards. This includes factors such as at what zoom level to hide the item, where to place the associated text, what size text to use, what layer it is rendered on, etc. Defining these parameters for each object on the chart is part of the digitizing process, and also involves a human cartographer. Mistakes can be made...

Hope this helps.

It does, thanks. And it improves my main point that "the computer" isn't the one making decisions.

-Chris