Displaying 20 results from an estimated 7000 matches similar to: "custom point shapes"
2012 Aug 15
1
shade overlapping portions of circles (or other shapes)
I'm making some illustrations and it would be convenient to
automatically shade the overlapping portions of circles. These
illustrations are for Social Choice theory, a field in political
science and economics. I've wrestled together some examples so you
can see what I mean, but have not mastered the "color overlapping
sections" problem (as you will see):
2009 Dec 04
1
multidimensional point.in.polygon??
Hi,
I seek to identify those points in/outside a multidimensional convex hull
(geometry::convhulln). Any suggestions?
Background just in case I'm going down a really wrong road:
Given an observed data set with one dependent/observed variable (Y) and
multiple (3 to 10) independent/design variables (X1, X2, ...) I want to
increase the number of points by interpolating. I'm using
2007 Sep 07
1
Finding convex hull?
Dear UseRs,
I would like to know which function is the most efficient in finding
convex hull of points in 3(or 2)-dimensional case?
Functions for finding convex hull is the following:
convex.hull (tripack), chull (grDevices), in.chull (sgeostat),
convhulln (geometry), convexhull.xy (spatstat), calcConvexHull
(PBSmapping).
I also would like to know if there is a function that can be used
2009 Nov 24
2
convex hull for cluster analysis
Dear R gurus and users,
I seem to have problem finding the right tool for plotting convex hulls over
2D plots, after a cluster analysis. In fact I would like to draw a convex hull
in 2D for a generic group of points. I found a "convhulln", but this doesn't seem
to give me a convex hull. Here is what I do:
> library(mvtnorm)
> Mean <- c(2,1)
> Sigma <-
2003 Oct 11
1
Simplex "Out of Bounds" Error
I am running the following code (testing the use of the simplex function to
determine if a point is in the convex hull of another set of points or not):
>a <- c(0, 0)
>A3 <-matrix(c(1,2,3,4,1,1), ncol = 2, byrow = T)
>b3 <-c(1.5, 3.5, 1)
>simplex(a = a, A3 = A3, b3 = b3)
and the following error message appears:
Error in simplex1(out1$a[1:(n + m1 + m2)], out1$A[, 1:(n + m1
2006 May 12
1
[ESRI-L] outline polygons of point clumps
Sorry, I did not make my question clear. Since I have a point theme
with many points, some of them may clump together. the problems here
are:
1. how to find clumps in a point theme?
2. the convex-hull extension I found only deal with all the points in
a theme at each time? how to make each convex hull around each point
clump automatically?
Thanks.
Xiaohua
On 5/12/06, Bob Booth <bbooth
2001 Sep 22
2
Finding a 3D convex hull in R
Dear List Members,
I'm presently carrying out morphological analysis of a data set of neuronal
structures. These are essentially 3D binary trees. In due course I will be
trying to use discriminant analysis or other methods to classify these
neurons based on morphological variables such as total tree length, segment
number etc.
I would like to calculate a 3D convex hull for a set of X,Y,Z
2011 Apr 16
1
Applying interpolation within a convex hull
Hi there,
I have been using the Tps function (within the Fields package) for a while
now to interpolate different sedimentary units. Due to the method of
formation of the units I know that at some edges the thickness of the unit
decreases to zero. I was wondering if there was someway to specify that the
interpolation only occurs within the convex hull of the data, outside of
which the the values
2009 Feb 18
1
alpha shape function
Hi all,
I want to approximate te shape of an area defined by a set of points.
The convex hull is not good enough, but I think that an alpha shape
would be fine. I did an RSiteSearch(), google search, RSeek.org search,
looked at the CRAN Views, but was unable do find a function in R that
computes the alpha shape. Does anyone know if there is such a function
in R?
Theank you very much.
Moacir
2001 Dec 10
1
high dimensional convex hull
Does anyone know of a R package that will determine the convex hull of a
high-dimensional dataset (say 4-10 dimensions). I know chull works for
2D data.
I'm neophyte to R and convex hulls so please keep it simple.
Many thanks
Ben
--
Ben Stapley.
Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD.
Tel 0161 200 5818
Fax 0161 236 0409
2005 Oct 03
2
interpolation using akima (PR#8174)
Full_Name: Jonathan Lees
Version: 2.0.1
OS: linux-gnu
Submission from: (NULL) (152.2.75.65)
there is a problem with calculating the convex hull in 2-D interpolation using
the codes interp fromt eh akima package:
x =c(0.6505304, -1.1821562, -0.2600792, 0.7913716)
y = c(1.0424226, 0.1754048, -1.4523334, 0.2349112)
z = c(0.000, 3.042, 0.370, 0.122)
EX = seq(from=min(x), to=max(x),
2011 Oct 12
1
reasonable theory?
Before coding this in C, I wanted to test the idea out in R.
But I'm unsure if the theory is well-founded.
I have a (user-supplied) black-box function which takes R^n -> R^3
and a defined domain for each of the input reals.
I want to send some samples through the box to determine an
approximation of the convex hull of the function's range.
(I'll use the library from
2007 Mar 24
2
sampling from the unoform distrubuton over a convex hull
Dear list,
Does anyone have a suggestion (or better still) code for sampling from the uniform distribution over the convex hull of a set of points?
Many thanks and best wishes,
Ranjan
2014 Oct 12
1
Is xyz point inside 3d convex hull?
Hi everyone,
I wonder if there is a code in r that can generate a 3d convex hull from a data-frame containing 3 columns and then use another database with the same three columns and for each row determine if the xyz point is inside or not the convex hull generated with the first database?
The package geometry allows to calculate a hull and it's volume. I was planning to calculate the volume
2006 May 02
2
Concave Hull?
I am modeling a trend surface using trmat and want to trim the resulting matrix to the area enclosed by my real data (i.e., remove all the extrapolated areas). I was using chull and in.chull to calculate the convex hull and change all the other values created by trmat to NA. However, my real data has portions that are slightly concave so chull would give me slivers that are extrapolations from
2009 Mar 09
2
Chull function
Hi everyone,
Using a simulation, I have to find what are the probabilities that, in a square region, the convex hull is a triangle, using the "chull" function. However, I have a hard time with the chull function, i did not see many examples in which the chull function is used. I searched a long time on google, but I did not find nothing. So, if anyone can help,
Thanks!
2011 Jul 16
1
MatchIt Package
Hi there dear R users!
Anyone knows why does matchit function returns error whenever the "hull" option is used (either "hull.both", "hull.control" or "hull.treat"). Things work well with all the rest of discard options.
This is the error msg.
>m.out.base <- matchit(formula=f, data=d, method=m, discard="hull.control")
[1]
1999 Aug 30
1
convex hulls
Does anybody know if there are functions to:
1. Define a convex hull on a space with more
than 2 dimensions? chull just works for a plane.
2. Numerically select elements within a given complex
hull.
Thanks!
Dr. Agustin Lobo
Instituto de Ciencias de la Tierra (CSIC)
Lluis Sole Sabaris s/n
08028 Barcelona SPAIN
tel 34 93409 5410
fax 34 93411 0012
alobo at ija.csic.es
2011 Jun 01
2
interpolation and extremum location of a surface
Hello,
I have a x,y,z file.Z is not corresponding to a simple analytical function of x and y (see below).
I am trying to find the minimum location of this surface and the z value corresponding to this location by a spline interpolation or from a polynomial fit.
I tried with the akima package but as the location of the point I am looking for (the minimum) is outside of the convex hull it's
2001 Jun 02
2
inout() in splancs working properly?
I have a problem with function 'inout()' in package 'splancs' on CRAN-R
Version 1.2.3 under FreeBSD4.3-STABLE.
The following script produces and draws points and a polygon-surrounded
area. Repeating the same script many times shows, that points on the
polygon-line often, but not always, are outside of the polygon-area.
library(splancs)
# dataset with polygon (convex