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3D Plot Extrapolation Question

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  3D Plot Extrapolation Question K Dub <kennethwright1974@gmail.com> - 2014-09-09 08:49 -0700
    Re: 3D Plot Extrapolation Question Karl <mail.kfr@gmx.net> - 2014-09-09 19:08 +0200
    Re: 3D Plot Extrapolation Question Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2014-09-10 01:04 +0200

#2574 — 3D Plot Extrapolation Question

I am currently trying to create a 3D plot of a given set of Datapoints.

The problem I am running into is that the program by default wants to extrapolate my 3D sheet beyond the extents of my data.

Is there a way to disable this extrapolation so that the graph stops where my datapoints cease? (When looking at my graph directly from the "top-down" it should look triangular in shape like my data point cloud does, instead it extrapolates out and fills in the full square of the graph area.

Thank you in advance for your responces.

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#2575

i assume you did

	set dgrid3d
	splot filename using 1:2:3

? Trouble is, dgrid3d has no meshing algorithm implemented, and even
worse (for you), it only steps in after the data has been run through
the "using" statement, so you can´t filter out unwanted grid points
using something like this

	splot fname 1:2: ((f($1,$2)) > 0 ? $3 : NaN)

(where f() is a function that returns a positive value for all x,y
values you want to show up)

However, you can first use dgrid3d mode to plot the square grid to a
temporary file ("set table"), and then switch if again off.

Plotting the temporary file without dgrid3d enabled, you can sort out
unwanted points with the ternary operator. (add "with lines" to splot)

  Karl




Am 09.09.2014 17:49, schrieb K Dub:
> I am currently trying to create a 3D plot of a given set of Datapoints.
> 
> The problem I am running into is that the program by default wants to extrapolate my 3D sheet beyond the extents of my data.
> 
> Is there a way to disable this extrapolation so that the graph stops where my datapoints cease? (When looking at my graph directly from the "top-down" it should look triangular in shape like my data point cloud does, instead it extrapolates out and fills in the full square of the graph area.
> 
> Thank you in advance for your responces.
> 

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#2576

Am 09.09.2014 um 17:49 schrieb K Dub:

> The problem I am running into is that the program by default wants to
> extrapolate my 3D sheet beyond the extents of my data.

No, it doesn't.  Not by default, anyway.

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