dist_from_coast.zip

Code calculates the minimum distance from input vector of lat/lon points to any coastal point (including major lakes).
Two distance options: great circle distance, which is precise but slow (non-vectorized); mean distance with cos(latitude) weighting, which is less precise but fast.
Also includes option to only return distances less than a threshold value. This greatly increases speed for cases with many input lat/lon points located in a relatively small region of Earth.

Code uses coast.mat data that comes with MATLAB distribution, and it uses vdist function from MATLAB file exchange for great circle calculation (included in this .zip file).