hi @galuardi can you please add a text file stating how to use this function or code. about boar

[galuardi]

I don't know which function you mean. there is an example in the package documentation

library(boaR)
# some good color ramps for gradient mapping
chlgradcol =   colorRampPalette(c("#00007F", "blue", "#007FFF", "cyan","#7FFF7F", "yellow", "#FF7F00", "red", "#7F0000"), interpolate = 'spline', bias = 2.0)
sstgradcol =   colorRampPalette(c("#00007F", "blue", "#007FFF", "cyan","#7FFF7F", "yellow", "#FF7F00", "red", "#7F0000"), interpolate = 'spline')
# load some satelite data originally downloaded here (as a netcdf file):  http://coastwatch.pfeg.noaa.gov/erddap/griddap/index.html
data(satdata)
# Blended SST image
x11()
tfront = boa(sst$lon, sst$lat, sst$DATA, direction = T)
par(mfrow=c(1,2))
plot(tfront[[1]])
title('Direction')
plot(tfront[[2]], col = sstgradcol(100))
title('Gradient Magnitude')
# SeaWifs chlorophyll image
x11()
cfront = boa(swchl$swlon, swchl$swlat, log(swchl$chl), direction = T)  # be sure to take the log of the chl 
par(mfrow=c(1,2))
plot(cfront[[1]])
title('Direction')
plot(cfront[[2]], col = chlgradcol(100))
title('Gradient Magnitude (Ratio)')