[talk-au] JOSM Scanaerial plugin on NSW LPI layers

[Ross]

On 25/01/16 14:31, Ian Sergeant wrote:
> On 25 January 2016 at 14:48, Ross <info at 4x4falcon.com> wrote
>
>> How do you know it is the physical feature?
>> Just because it follows approximately the feature does not mean it is.  When originally gazetted the physical feature may have been located differently (roads, railways realigned, rivers making new paths)  Don't automatically assume that the feature is still in the same place without looking at the imagery or physical survey.  Don't assume that the boundary changes to the new position of the road, etc.
> There are numerous ways you can 'know' something.  Legislation
> (including regulations, court judgement) is often the primary thing
> involved here.  I'm not calling on people to guess, but we should bear
> in mind that OSM is an evolution, and we have often used these
> features in evolving the map until we locate or have free access to a
> definitive source.
>
So you check each and every time for a source that shows the boundary 
you are working on is the physical feature and then provide the source 
in a tag?

As you suggest most people will just guess and a lot of the time it may 
be so but it still causes issues with later changes and corrupting the 
original data (such as the NSW reserves boundaries).

And the guess does not get fixed there are many locations where roads 
are still on admin boundaries but the boundary is no long there (changes 
to boundaries) or the road has moved but  nobody comes back to correct it.

>> But the border has not changed the river might have but there is no change to the border from when it was first surveyed/gazetted.  The border is the line as when gazetted, not as where the riverbank is now.
> I think you're wrong.  The border has been defined by High Court
> Judgement as including accretions and erosion.  Including landslip
> such as in the Ward case.
>
> Of course, where the river has fundamentally changed course, the
> original course remains the boundary.  But gradual erosion actually
> changes the border.
>
> Ian.

But not in all cases as your previous post suggested and the location I 
pointed out shows.

Cheers
Ross