random multi band raster stack

[wegmann]

Hello,

NLMR is a great package and perfect for a variety of random landscapes. I just stumbled across a small issue:

I try to create random multi-band stacks were the band values are corresponding e.g. if low value in raster A always high values in raster B, similar to an actual remote sensing multi-band raster stack.

Have you already had a similar issue and could provide a way how to achieve it? thanks

[marcosci]

Hi Martin,

I am not sure if I can follow there - you mean something in the line of RGB bands? Aren't there the values positively correlated?

If you meant something like that, you only want to add noise and not the general direction of the pattern, or? This could be done via:

library(NLMR)
library(landscapetools)

landscape_red <- nlm_fbm(50, 100) 

landscape_blue <- util_merge(landscape_red, 
                             nlm_fbm(50, 100), 
                             scalingfactor = 0.8)

landscape_green <- util_merge(landscape_red, 
                              nlm_fbm(50, 100),
                              scalingfactor = 0.8)


show_landscape(list("Red" = landscape_red,
                    "Blue" = landscape_blue,
                    "Green" = landscape_green))

... or is the pattern supposed to look exactly vice versa?

[wegmann]

Hi Marco,

thanks I will check it out. Looks good. I wanted to simulate actual multi band remote sensing data patterns. I will check if your suggestions works out. best, martin

[marcosci]

Sure, let me know if that is what you wanted, otherwise I'll try to come up with a solution.

[wegmann]

Hi Marco,

I tried it but I did not get a result I was expecting. I stacked the raster files and plotted them as RGB.

library(raster)
 x <- stack(landscape_blue, landscape_green, landscape_red)

 plotRGB(x, 3,2,1,stretch="lin")
 plotRGB(x, 1,2,3,stretch="lin")

first the maps should be quite colourful and secondly the band combination should change the colour settings while keeping the patterns.

With an actual remote sensing multi-band raster stack it would look like this:

 library(RStoolbox)
 data(lsat)
 plotRGB(lsat, 3,2,1, stretch="lin")
 plotRGB(lsat, 4,1,3, stretch="lin")

and it would be great to create corresponding random layer for mimicking a multi-band raster set where the single bands/values are linked to each other.

sorry, if I have missed some util_merge options or other commands that could do that already. thanks, Martin