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2019-04-21 09:58 BST

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IDProjectCategoryView StatusLast Update
0000466Canalplan Route Planningpublic2018-06-01 22:56
ReporterNx 
Assigned ToNick Atty 
PrioritynormalSeverityminorReproducibilityalways
StatusassignedResolutionopen 
PlatformFirefoxOSWindowsOS Version10
Product Version9.28Product Build9.31 Apr 21 
Target VersionFixed in Version 
Summary0000466: Time taken between two points varies based on method chosen
DescriptionI wanted to see how long it would take to get from Hawford Visitor Moorings to Tewkesbury Visitor Moorings. I used two methods for this:
1. A simple 'furthest place' route
2. A route starting and ending at these two places
0000001 Indicated that in a 6 hour day, I could only get as far as Upton Bridge (short of Tewkesbury)
0000002 Indicated that it would take 5 hours and 38 minutes to get all the way to Tewkesbury Visitor Moorings
Steps To Reproduce1. Plan a route of type Furthest Place starting at Hawford Visitor Moorings
2. Set the trip length (Duration) to one day of 6 hours and don't return to the start
3. Note the furthest you can get on the River Severn is to Upton Bridge
4. Plan a new route of type Normal starting at Hawford Visitor Moorings and ending at Tewkesbury Visitor Moorings
5. Set the trip length (Duration) to one day of 6 hours
6. Note that the planned route indicates a total time of 5 hours 38 minutes
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~0001807

Nx (reporter)

I've realised that it may not be clear that there is a significant difference in the timings proposed by each method. By trial-and-error (increasing the length of a day) it is possible to show that the Furthest Place method calculates the time from Hawford Visitor Moorings to Tewkesbury Junction to be 8 hours. This is clearly significantly longer than the 5 hours 38 minutes calculated by the normal method.

It also seems that this difference in calculation is not a general problem, but in some way relates to this particular route. Trying similar tests on other random places around the waterways, I don't see the same difference in calculation.

~0001808

Nick Atty (administrator)

Last edited: 2018-06-01 19:53

View 2 revisions

Thanks for the research. I'm going to guess, based on this, that it's probably something about furthest place not taking flow on rivers into account (which would explain why this route shows it and others don't). I'll think about it, and about what to do about it (because incorporating it will break out-and-back furthest place).

~0001809

Nx (reporter)

That makes sense and I can see why it might be hard to address. Its unfortunate that I like using Furthest Place on rivers because its a good way to identify which of the few mooring spots might be within reach in one day. However, your explanation of the cause suggests a workaround - i can just calculate over two days and use out-and-back. This should give me a pretty good estimate.

Hmmm... I just tried this and found it doesn't work. I can still only get as far as Upton Bridge (and back). It looks like out-and-back must simply do the same as the one-direction-only, but using half the time. Even if I try a single day of 12 hours, I only get to Upton Bridge.

Maybe this is just a limitation I'll have to live with.
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-Issue History
Date Modified Username Field Change
2018-05-31 16:13 Nx New Issue
2018-05-31 19:01 Stephen Atty Assigned To => Nick Atty
2018-05-31 19:01 Stephen Atty Status new => assigned
2018-06-01 15:57 Nx Note Added: 0001807
2018-06-01 18:14 Nick Atty Note Added: 0001808
2018-06-01 19:53 Nick Atty Note Edited: 0001808 View Revisions
2018-06-01 22:56 Nx Note Added: 0001809
+Issue History