Good afternoon,
I've come up with a graphic with annotation to illustrate this
better, but how can I attach it to post in this forum?
Regards,
JD
--- In [email protected], "mark2atsafe" <[EMAIL PROTECTED]> wrote:
>
> Hi J.D.,
> I'm having trouble visualising this one. Can you run up a quick
> sketched image to illustrate what you mean?
>
> I'm thinking that you must also be using the 2DPointAdder to add the
> point onto the modified line when you've attached the coord values -
> else those values wouldn't do anything.
>
> At that point I'd think it depends on the direction of each line
> relative to each other. ie if they run in the same direction then the
> start point of the modified line would be the same as the start of the
> unmodified line (because you've copied it from one to the other)
> giving a distance value of 0 - and the same with the end point.
>
> If they run in opposite directions then the start/end points would be
> different, so it wouldn't be 0, but you'd still get the same value for
> each (because each measurement is the same, just in different
directions).
>
> But like I said, I can't quite visualize this, and might have it wrong!
>
> Regards,
>
> Mark
>
> Mark Ireland, Senior Product Specialist
> Safe Software Inc. Surrey, BC, CANADA
> [EMAIL PROTECTED] http://www.safe.com
> Solutions for Spatial Data Translation, Distribution and Access
>
> --- In [email protected], "jamison_leach" <hemsidan@> wrote:
> >
> > Good morning,
> >
> > I have a Workbench file that currently does the following:
> >
> > 1. uses CoordinateFetcher to retrieve the start and end points of
> > lines.
> > 2. merges the start/end point coordinates from these lines onto
> > spatially modified versions of the same lines (using FeatureMerger
> > with Merge Type 'Attributes Only' and Join Attributes set for a common
> > field).
> > 3. calculates the distance from the start point of each modified
> > line to both the start and end points of the unmodified line
> > (Literally, I suppose, LengthToPointCalculator doesn't use the
> > original line's start and end point coordinates for the distance
> > calculation, but uses the points on the modified line closest to the
> > original line's start and end points).
> >
> > So ultimately, this Workbench file should provide me with two
> > distances, both calculated from the start point of the modified line:
> > 1. To the point on the modified line closest to the original
> > line's start point
> > 1. To the point on the modified line closest to the original
> > line's end point.
> >
> >
> > I have run this process on certain files and it seems to work fine.
> > However, with the latest set of files I ran, most of the distances do
> > not appear to be correct. The coordinates of the original line's start
> > and end points look good coming out of CoordinateFetcher, but when
> > LengthToPointCalculator estimates their distance from the modified
> > line's start point, the two distances come up equal, either as '0' or
> > a non-zero, but still equal value. If I'm thinking correctly, the
> > original line would usually have to start and end at the same point
> > for both distances to be the same, but the start and end points are
> > very different.
> >
> > In other cases, the two distances appear to be correct, or at least
> > not the same as each other.
> >
> > Does anyone have any insight on this? Am I overlooking something?
> >
> > Many thanks,
> > J.D. Leach
> > U.S. Census Bureau
> >
>
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