Peter Langfelder wrote: > > Sorry, I'm not sure what you want to do in points 2-4. Shrink the > mountain vertically or horizontally? You can for example look up image > resizing algorithms if you want to shrink the area under the mountain > but keep the shape of the mountain (approximately) the same. For > cross correlation, simply do cor( c(mountainMatrix1), > c(mountainMatrix2)). The c() function takes values in a matrix and > "straightens" them out into a single vector. > > Peter > Sorry, I was not clear.
Step2: I want to shrink (by half) the mountain along XY (i.e. ignore height) based on the centroid value i find in step 1. Yes, I am looking for algorithms similar to image resizing, more specifically i want to use bilinear interpolation while resizing where neighboring 4 pixels are averaged. So, based on that concept, every value should be averaged with neighboring 4 values in the matrix. Is there any package in R which uses such algorithm? Step3: After step2, the relevant values of the mountain will be constrained to 11x11, however i want the final matrix size to remain 21x21 with zeros coerced where necessary. Step4: Yes, since i will be generating several such maps I want to use cross correlation to compare them for similarity. More specifically i need Pearson's correlation, seems like cor will do it. Thanks for the corrected z-coordinate formula. I needed just the X and Y coordinates to get the centroid because I want to shrink my mountain only along those dimensions. -- View this message in context: http://r.789695.n4.nabble.com/Centre-of-gravity-of-a-mountain-tp3032319p3035549.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
