Destination point given distance and bearing from start point

You have starting points:

xcoordinate, a list of x-coordinates (longitudes)

ycoordinate, a list of y-coordinates (latitudes)

num_samples, the number of samples in the plane towards the destination point

bearings:

heading, a list of headings (degrees)

and distances:

range, a list of distances in two directions (metres)

This is how you find the coordinates (x, y) along the plane defining a starting point and two end points, in MATLAB.

Compiling Clarkson's Hull on Fedora

A note on compiling Ken Clarkson's hull program for efficiently computing convex and concave hulls (alpha shapes) of point clouds, on newer Fedora

First, follow the fix described here which fixes the pasting errors given if using gcc compiler.

Then, go into hullmain.c and replace the line which says:



at the end of the function declarations (before the first while loop)

Finally, rewrite the makefile so it reads as below It differs significantly from the one provided.



Notice how the CFLAGS have been removed. Compile as root (sudo make)

Ellipse Fitting to 2D points, part 2: Python

The second of 3 posts presenting algorithms for the ellipsoid method of Khachiyan for 2D point clouds. This version in python will return: 1) the ellipse radius in x, 2) the ellipse radius in y x is a 2xN array [x,y] points

Matlab function to generate a homogeneous 3-D Poisson spatial distribution

This is based on Computational Statistics Toolbox by W. L. and A. R. Martinez, which has a similar algorithm in 2D. It uses John d'Errico's inhull function Inputs: N = number of data points which you want to be uniformly distributed over XP, YP, ZP which represent the vertices of the region in 3 dimensions Outputs: x,y,z are the coordinates of generated points

Computational geometry with Matlab and MPT

For computational geometry problems there is a rather splendid tool called the Multi Parametric Toolbox for Matlab Here are a few examples of using this toolbox for a variety of purposes using 3D convex polyhedra represented as polytope arrays. In the following examples, P is always a domain bounded 3D polytope array

Flower Bed

Recently I investigated Apollonian gaskets (a type of space-filling fractal composed of ever-repeating circles) for use as 'pore-space fillers' in a model I am creating for synthetic sediment beds. I came across a most excellent script here:

http://www.mathworks.com/matlabcentral/fileexchange/15987

In my Friday afternoon boredom, I have just modified some aspects of the program to create a function which simulates a pretty flower bed Some example outputs below - enjoy! Right, now back to work ...