Description Details Author(s) References Examples
Belkin-O'Reilly routine for detecting fronts from sea surface temperature and chlorophyll (and probably other) satellite imagery.
Package: | boaR |
Type: | Package |
Version: | 1.0 |
Date: | 2012-01-02 |
License: | GPL (>= 2) |
LazyLoad: | yes |
This package works on satellite imagery imported into R. This package contains three functions which iteratively perfom median filtering and front detection. This is a port from IDL code which operated on flat binary files directly. It is easiest (in my opinion) to import satellite data into R as a netcdf file using the raster
package.
Benjamin Galuardi
drdrumfish@gmail.com
Belkin, I. M. & O'Reilly, J. E. An algorithm for oceanic front detection in chlorophyll and SST satellite imagery. Journal of Marine Systems, 2009, 78, 319 - 326
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | 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)')
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