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Find Nearest Neighbors on Sphere

version 1.7 (12.5 KB) by

To be used with the GridSphere function to look up the nearest point to a query on a geodesic grid.

4 Downloads

Updated

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A geodesic grid is an even grid over the surface of a sphere. The algorithm is optimized for a grid generated by GridSphere and won't work on an arbitrary geodesic grid. All code is compatible with GNU Octave. The GridSphere function is available on the MATLAB file exchange at http://www.mathworks.com/matlabcentral/fileexchange/28842-gridsphere.
FindNearestNeighbors and GridSphere share some functions in common. Each package contains a copy of these functions so that both can stand alone. To eliminate duplicates, simply move all the files into a single folder and replace the shared files when prompted.

Comments and Ratings (4)

Fast and found it easy to use. Thanks!

Paul

Paul (view profile)

-- Wrong page. Comment intended for GridSphere code.

Paul

Paul (view profile)

Blazingly fast and well documented. Only an example would not have been unbecoming, e.g. to illustrate the fact that returned values are in degrees (whereas Matlab's sph2cart requires radians).

[lat,long] = GridSphere(1000);
latrad = deg2rad(lat);
longrad = deg2rad(long);
[x,y,z] = sph2cart(longrad, latrad, 1);
scatter3(x, y, z, 22);
axis equal vis3d;

Updates

1.7

Added a link to another FX submission that this submission uses code from.

1.6

Made minor corrections to comments. Removed write and execute permissions from group/others on all *.m files. Removed trailing whitespace and switched from 2 spaces after each period to 1 in the interest of readability.

1.5

Made code available as a toolbox and removed some unnecessary hidden files.

1.4

Replaced tabs with spaces so that the source code displays consistently in all text editors.

1.3

Replaced the ElementWiseMax function with an equivalent built-in function.

1.2

Added missing Logarithm function file.

1.1

Added missing function file.

MATLAB Release
MATLAB 7.9 (R2009b)
Acknowledgements

Inspired by: Geodesic Midpoints

Inspired: Grid Sphere

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