lustyd
Well-Known Member
Really important to understand this has nothing to do with the chart. This is a presentation layer technology that interprets vector data and CM93 charts would absolutely support such functionality.
Open CPN, UK charts. Admiralty & alternatives
- Thread starter Devon Boy
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Pye_End
Well-Known Member
On a raster chart I can zoom in and make the writing/symbols bigger. Vector have me hunting for glasses.
Vector can end up with too much uninteresting data, of too little important data. Raster have already been filtered by an expert eye, in the cold light of day/plenty of time/not knackered.
Vector can end up with too much uninteresting data, of too little important data. Raster have already been filtered by an expert eye, in the cold light of day/plenty of time/not knackered.
Refueler
Well-Known Member
I use full Commercial CM93 in my work ... and I agree that functionality would be there IF it was implemented - but its not. Of course data can be shown based on the program using the CM93 ...
ducked
Well-Known Member
Same tech as GIS, I suppose. I'dont mind you telling me that at all, (I did a very marginal and half assed remote sensing MSc, so could not be assumed to know it) but it doesn't seem to be a response to what I posted?
ducked
Well-Known Member
aqVtl does that, I believe. Again, I havn't actually seen it (yet?), just going by the documentation.
TBH I would have expected it to be one of the earliest functions to be implemented with this technology, but I know notheeeng
lustyd
Well-Known Member
Literally all of this can be changed on vector but not on raster, so you seem to have misunderstood the technology (or have a poor system).
On vector systems, writing and symbols are drawn on the fly to a size dictated by the system. The system can and often does allow the user to set text/symbol size. Vector systems I've used have always included the ability to turn various data on and off depending on user preference, along with the frequency of contour lines. They also allow user customisable colouring so are far more accessible for vision issues.
Raster labels and symbols are fixed size, like on paper, so while you may make them bigger you'll have a smaller field of view as a result. No way to turn off certain symbols on a raster either, if the cartographer decided you should see it that's what you'll see. Fine if your goal is navigation, but fishermen for instance aren't trying to navigate safely, they're trying to find and catch fish (on reefs, wrecks, etc.) and may need a different view.
AntarcticPilot
Well-Known Member
The problem arises that hazard to me with 1.6m draft might not be for a catamaran drawing 50cm. So the definition of hazard would have to be flexible, and also risk averse.
lustyd
Well-Known Member
In Navionics you have to configure your boat info including draft, air draft, beam and length for this reason. I believe the problem traditionally may have been a lack of compute power in the device which is obviously changing rapidly. I quite like that some systems can proactively colour the depth based on the vessel so instead of blue, light blue and white you can just have danger and not danger in any colour you like.
Refueler
Well-Known Member
This 'discussion' has been going on for years ... Vector vs Raster.
I can remember using Fathom charts ... and they were being phased out and replaced by Metric charts with COLOUR ! We lost such beauties as : Sea Monsters ... etc noted on charts such as the one from S. Africa to Antarctic ...
No sense of humour or 'character' in the coloured metrics.
Hours and hours of discussions about B&W vs Colour ...
I can remember using Fathom charts ... and they were being phased out and replaced by Metric charts with COLOUR ! We lost such beauties as : Sea Monsters ... etc noted on charts such as the one from S. Africa to Antarctic ...
No sense of humour or 'character' in the coloured metrics.
Hours and hours of discussions about B&W vs Colour ...
PaulRainbow
Well-Known Member
But, the route it draws assumes you will be sailing at LAT, so will route you around areas where you would have plenty of water if you left at a higher state of tide. Sailing on the East Coast means that pretty much every route that's auto planned will be longer than it needs to be.
I don't like or use auto routing, when just checking a route it's easier to miss something than it would be if starting from scratch, plus you can tailor the route based on the depths when you actually plan to sail.
Refueler
Well-Known Member
I have mixed feeling about Auto-routing ..... 50% of which I scrub and then do manually. But others - I usually tweak a point here and there to suit.
But like Car Satnav - sometimes its hard to understand why it takes a route ...
I've also noticed that despite having same user settings ... if I auto-route on my tablet .. while auto route on the Garmin UHD - they usually end up different routes !!
lustyd
Well-Known Member
Some of them do compensate for tides these days. Whether you trust it is a personal choice, but the technology is certainly there and available and I think it's foolish to dismiss it as we've seen with various other advancements over the years. There's no reason not to use auto routing for the initial broad brush and then tweak from there. There's also no reason you can't auto-route to sanity check a manually created route.
lustyd
Well-Known Member
I think as with car sat nav it'll become increasingly clear that you don't have to understand, but it's usually a bad idea to argue
I don't think we're there yet with marine navigation, but there's no reason with current tech that LNTMs couldn't be ingested by the system to route you around things you're unaware of. That will take some investment and understanding from those issuing the LNTMs. We've certainly seen this on roads and in the air though, so it's a well worn path.
AntarcticPilot
Well-Known Member
I'd actually regard that as dangerous. Recontouring the bathymetric data is fraught with potential for error, as frequently seen with Navionics crowd sourced data, where missing data is interpreted as licence to interpolate, rather than "no-one goes there so it isn't safe"!. The contours provided in UKHO data are based on far more data than is present on the chart, and are reliable and drawn so that any error will be on the safe side of indicating shallower water than it actually is. But recontouring on the basis of the selected soundings on the chart and the contours is not a safe or straightforward matter; there are many possible algorithms and they all give different answers! The only one where you get an estimate of the accuracy of the interpolation is Kriging, which is extremely computing intensive, even now with modern processors, as it has to examine all the data to create a semi-variogram.
tillergirl
Well-Known Member
With the several manufacturers' vector charts that I have, I have different data on different zoom levels. That is why I asked what zoom level do you use for creating a passage plan. On the several raster charts I have there are no changes as when I zoom in. The raster chart is (effectively) a single image of a paper chart. Yes of course raster charts will have different scales. Typically I use 1:50,000 because I know the waters a little but in the area there are charts that have different scales - actually 1:100,000. I think 1:6,250 is the most detailed I have in the area. If I am using a raster chart on my PC (i.e. without GPS) if I reach the boundary I can click onto the adjoining raster chart. If I am afloat using the same raster charts on my laptop or tablet WITH GPS, the software handles the boundary issue, i.e. as the vessel icon reaches a boundary it will immediately switch to the adjoining chart. Of course raster charts have boundaries, everybody knows that but there are no boundary issues.
Yes a raster chart wil pixelate. However the software eventually prevents zooming and in the platform I am using the zooming stops just as pixelation starts and the zooming is already well past what is needed. So for practical purposes I am never trouble by pixelation.
The comment about immediate updates is interesting. Say, if a channel you use has 6.5m CD last year but the UKHO are reporting 0.7m very adjacent this year, would you be interested? All charts are dependent on the data and primarily leisure charts whether raster or vector are dependent on the UKHO. Yes, there are examples of vector charts being updated via local authority notices to mariners which is excellent, but the primary business is dependent upon how frequently the manufacturers buy 'updates' from the UKHO. Of course the UKHO will not tell me how frequently they send out 'updates' to various manufacturers because that is commercial in confidence. But if you monitor updates you can start to realise the pace at which updating taking place.
Is the new depth of 0.7m important. Well let's hope not. One manufacturer of vector charts hasn't bothered to update it yet (that's as of today) - it was reported by the UKHO on 12th September, 2024. A second manfacturer did update it on 12th January, 2025 but failed to do the contours instructions properly; indeed if you switched to their Sonar Chart you would not only not see the contours correct, nor see the 0.7 right next to where 6.5 is still shown!
Monitoring vector charts also demonstrates that they make choices about detail at different zoom levels. I suspect someone made a decision on what vector zoom level should display which data. Um. At what zoom level would you want to see something critical on a vector chart. And if your 'autoroute' went over a critical point would yu expect it to alert you?
I don't think there is any point in arguing whether vector charts or raster charts are good or bad: they are just different and have some advantages and disadvantages. One advantage said of vectors over rasters is Autoroute. I agree with Paul. It does have some value; such as quickly proposing a route for consideration but I do think chopping ad changing zoom levels to plan it properly does seem to me quite tedious. I see the comment about land based Sat Nav. Did you know we actually have road signs up in Colchester saying 'Don't use Sat Nav'? The autorouting there doesn't work and costs a lot of money!
What is important is knowing about the currency and accuracy of echarts.
lustyd
Well-Known Member
You can't have it both ways. If you think it's acceptable for you to add the tide height to the chart and be safe then it is if course the same if a computer does it. If you think it's not safe to add tide height, then you should also be assuming LAT.
AntarcticPilot
Well-Known Member
As indeed I mostly do.
lustyd
Well-Known Member
That's a presentation issue, not a chart issue. You or your plotter have a setting that decides the detail. The chart is a single set of data in layers, which can be turned on and off.
Yes, but then I quite like the Navionics crowd sourced data which is often much more useful than the standard data. In many places it produces a higher resolution view of a location. It can also be produced with a handheld echosounder on the fly in a dinghy before taking in the big boat.
No, the chart and the chart maker don't make those choices. A vector chart is just a data set consisting of points, lines and polygons with some metadata which can be interpreted by various systems. The plotter or software producer may make those choices, they may provide some defaults, and hopefully they provide an interface for you to change those choices. If not, change your plotter but it's not a chart issue.
lustyd
Well-Known Member
Sorry I thought you posted that above but it was Paul
Your argument makes more sense now!
Refueler
Well-Known Member
This echos my point of some who think that zooming in on vectors can increase detail more in soundings etc....