Feedback on I think mapswipe

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Feedback on I think mapswipe

john whelan-2
I'm looking at project 3890 which apparently was prepossessed by mapswipe.

I think the mapswipe overlay has now been removed but what I have noticed is a number of highways in a straight line are not connected up.  You get a stretch of highway then nothing other than a faint mark on the imagery followed by another stretch of highway.

Whatever the cause it means a lot more work has to be done when validating joining up all the unconnected highways and I don't think its one bad mapper its apparent on a number of tiles and mappers.

It might just be coincidence and nothing at all to do with mapswipe but that's not my gut feel.

Cheerio John

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Re: Feedback on I think mapswipe

Pat Tressel

I think the mapswipe overlay has now been removed but what I have noticed is a number of highways in a straight line are not connected up.  You get a stretch of highway then nothing other than a faint mark on the imagery followed by another stretch of highway.

What that pattern immediately makes me think of is that people were working within a grid cell, and just mapped the part of the highway within their cell, and that the intervening cells have not yet been mapped.  If the spacing isn't the same as the TM grid, perhaps some folks are using a different grid, perhaps something self-imposed.  For instance, they might map the area that shows in one screen at whatever zoom level they're using, save their work, go off to dinner...

Is the faint mark on the imagery a mapped way of some sort, or is it the actual highway image?

-- Pat

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Re: Feedback on I think mapswipe

john whelan-2
It was apparent on at least a dozen tiles with different mappers.  One classic one was a highway that ran top right to bottom left, four segments of highway and three of no highway and that sort of matched the pattern on the tile view in TM.  Several places where the image was a bit darker the segments were missing.

There was no regular pattern as you might expect with mini tiling or grid.

My thoughts run along the lines of a large IPS monitor shows the contrast and image better than a small smartphone screen but that's only a guess.

Cheerio John

On 16 December 2017 at 22:20, Pat Tressel <[hidden email]> wrote:

I think the mapswipe overlay has now been removed but what I have noticed is a number of highways in a straight line are not connected up.  You get a stretch of highway then nothing other than a faint mark on the imagery followed by another stretch of highway.

What that pattern immediately makes me think of is that people were working within a grid cell, and just mapped the part of the highway within their cell, and that the intervening cells have not yet been mapped.  If the spacing isn't the same as the TM grid, perhaps some folks are using a different grid, perhaps something self-imposed.  For instance, they might map the area that shows in one screen at whatever zoom level they're using, save their work, go off to dinner...

Is the faint mark on the imagery a mapped way of some sort, or is it the actual highway image?

-- Pat


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