[gdal-dev] GDAL C++ Api, create new line segments from point layer

[ChiefDan]

Matt Hanson-2 wrote
> So you've got a series of points in your point layer, and a series of
> lines
> in your line layer, and for each point on your points layer, you want to
> find out which line this falls on.

--I'm able to do this already.


Matt Hanson-2 wrote
> Is that right?  It sounds like you've done this part.  However, I'm not
> sure what is meant.  Is there an exact matching point on the line (i.e.
> same exact coordinates), or are you finding the line that the point falls
> on (using some sort of buffer or tolerance)?

--If you look at the picture above, those points are on the lines, but there
is not necessarily a corresponding point in the linestring, most likely
there is not.


Matt Hanson-2 wrote
> If you are just finding the line that it happens to fall on, (I think this
> is what you meant by "not end points"), then are you finding the closest
> point that actually is part of the line?

--I'm thinking to have a network of point-line-points for path finding. Pick
any one of the green points above, I need to create line segments from that
point to any point in any direction on the line that point is on to the next
point. In the end, the layers would visualize in the same manner, however
the original line(s) would now have end points at those green points.


Matt Hanson-2 wrote
> If you have found the closest point on the line, then from there I think
> it's easy to walk up and down the line by retrieving the points in order.
> However, if you currently only have the linestring and the point
> coordinates then use distance to find the actual closest on-line point.
> 
> 
> Do I have this mostly right or have I only managed to confuse things more?

--I'm sure I am not explaining it well as this is my first foray into path
finding and preparing the data so far has been the most difficult part. I'm
not fluent in GIS either so I think I'm lacking in proper vocabulary.




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