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Compare two 3d plots

3 messages · Chris Harding, Ab Hu

Original
Ab Hu
# 
Hi,


I am still learning and find it very helpful in my research. I have searched 
before posting this and could not figure out if there is a way to compare 
matrices the way i am describing below:

I have a matrix of 64 cols and 64 rows which mostly has lots of zeros but has 
other non-zero positive integers (usually grouped close to each other) in the 
matrix. I use persp to get a 3d plot and it looks like a mountain with its peak 
roughly in the center. I have several such matrices all 64-by-64 but with 
different integers in the matrix such that the mountains look very different.

Problem:
If I overlay one 64-by-64 matrix over another, there will be many differences in 
the mountains (such as, height[this is easy], shift towards one direction, 
surface area[PeakArea from library sp], circumference), I want to quantify those 
differences. I have some of them figured out but want your inputs to this. I 
want to be able to compare several mountains with one another and rate them for 
similarity/differences with one another.  

Any help would be great.

Thanks,
Ab
Ab Hu
# 
I'll check that book out and/or get help from the authors. But i was still
hoping there is some basic way to compare these 3d plots using R. 
By the way, I figured out i can draw these plots using command "image" and
get a gradient heat map or topography map with gradients. Is there a
function in R to process the colors in these images and give me the
difference between two images?