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Charts with ferry routes


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I'm looking at layering ferry routes onto the online nautical charts available on CoastalPaddling.com and I would love to get some feedback from paddlers who use charts on this point. I have put the ferries up as an optional layer for browsing on the site. However, they are not going on the site's nautical charts yet without some further input.

The ferry route information comes from a global open-source data provider called OpenStreetMap.org, whose data is widely used by mapping services — kind of like a Wikipedia for maps. So no, I did not personally research each ferry route!

There are at least two areas of concern: accuracy, and visual appropriateness.

Accuracy: The route info seems fairly accurate based on the few I personally know about. What kind of inaccuracies exist? Well, the Salem Ferry route is shown slightly outside of some of the channel markers in Salem Sound, but I know it actually does follow the channel. So, close enough that one would know what to expect, as long as you don't take the route as the absolute literal truth. For other routes I think we could expect similar minor departures from reality, but perhaps worse.  I would love it if folks who know ferry routes could go to coastalpaddling.com and turn on the Ferries layer: see if the routes you know match your knowledge, and post what you find out.

Appropriateness. As a test, I've included a sample Casco Bay chart below including the ferries for that area as dashed blue lines. Let's assume that these routes are "pretty accurate" as per above. The question is: is this information useful enough to paddlers to include in the chart, since it adds some extra clutter? Also, everything else on the chart is 100% accurate in terms of placement, but let's say these ferry routes are "pretty close". OK or not OK? If not OK, would a verbal disclaimer "ferries may not follow marked routes" make you feel better? Or will some people look at a chart and think, "well, I'm not going where the dashed line is shown, so the ferry won't hit me."

ME-Casco-South.thumb.png.bb4a6e766b4fcd5a1714e8fcf759ec0b.png

(Note: the resolution of this chart was reduced to allow the image to be uploaded.)

Thanks for your help on this!

Joe

Edited by Joseph Berkovitz
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1 minute ago, kate said:

Close enough is good enough.

Indeed!

My concerns are timetables for these transits if I am fog-bound, or paddling after dark, and must cross a busy stretch of water. A prepared paddler will have researched this already, yes?

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I  agree that is a valuable addition.  

Regarding ferry route accuracy: on a recent paddle trip to Swans Island, we noticed during our long approach to our take out near  the ferry dock that the incoming ferry ahead of us went inside rather than outside (as expected) green can 3 on its approach to the ferry dock; this was close to high tide so presumably the ferry operators may cut corners or otherwise slightly alter routes  as experience and prudence dictate.   This in turn  suggests that here and there might be some deviation in  ferry routes  we  see on maps and  charts.

Chart 1 shows the actual approach of the ferry as we witnessed it. You can see the turn inside green can 3
Chart 2 shows how this route could be shown on your charts: a  wider swath ( translucent  so that  none of the chart is blotted out)  might suggest some reasonable  expected deviation in a ferry  route.
Chart 3  (Grand Manan Ferry route) shows how this might  look in  the context of a large scale chart.  

Your chart work is fantastic!    

swans ferry 1.jpg

swans ferry 2 .jpg

Grand Manan Ferry .jpg

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Joe:

Impressive work.

Believe Peter's suggestion  giving ferry routes a wide berth/wider marking a good one.  With regard to the Swan's ferry, I wonder if the white/orange can suggests they normally turn in prior to green buoy.  FWIW, Google maps seems to show this.

Ed Lawson

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Thanks for all the valuable input on this topic so far. I plan on regenerating the charts with ferries added.

Here are a few responses:

- schedules change frequently and with this scale of operation I cannot look them all up manually on regular intervals. Instead my approach is to include links directly to the ferry operator websites, letting you jump from CoastalPaddling.com directly to the ferry info.  If you click on any ferry route, the site will show you the information it has about that ferry in a popup window (see example for Swans below). The schedule won't be in the popup, but the name of the ferry is a link to that info, where I have it. I would love it if people could please use the feedback feature to report where this info is missing!

- Re Swans: amazingly enough, the existing data that I got from my source seems exactly right! I recently visited Swans also and saw the same behavior you describe, but the data is correct with no adjustments from me. Check it out with this link; a screenshot is below:

image.thumb.png.2534f78c55251d440423b95ad35d14bd.png

- Grand Manan ferry is a bit more interesting as what's on the map deviates from the data I got. Both are shown here thanks to the fact that the Canadians actually DO put ferries on their charts:

image.thumb.png.b80b210ed60f2acafc9b06db31f2b864.png

Having just visited GM and seen the ferry in action, I suspect that the site data (blue line) is actually closer than reality than the official chart (black line).

 

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