[R-sig-Geo] SST and chlorophyll data extraction in R

[Michael Sumner]

The crux is hdf4, the format once you bunzip2 these files, and while geo
metadata is unstandard the L3m variants are trivially longlat complete
global grids on Atlantic view.

Raster/rgdal makes it easy though manual and installing hdf4 for GDAL is
easy on ubuntu, but  non existent for R on windows, due to zlib license I
believe.

It sucks, and be apprised NASA is moving to Netcdf4 just to complicate life
further. L3m is simplish relatively in the new regime, but on windows you
must compile for yourself.

M


On Friday, September 18, 2015, Antonio Silva <aolinto.lst at gmail.com> wrote:
> Dear R-Sig-Geo fellows
>
>
> This is my first post to this list. My name is Antonio Olinto and I work
as
> researcher at Fisheries Institute, São Paulo, Brazil.
>
>
> Well, I'd like to hear suggestions on how to proceed in R to extract sea
> surface temperature and chlorophyll concentration data and calculate some
> statistics from MODIS/AQUA data in a given area.
>
>
> I used to do this in QGIS but available statistical parameters are limited
> and I had to work with one image at a time. I found a reference to a
> package named satin (
>
https://www.r-project.org/conferences/useR-2009/slides/Villalobos+GonzalezRodriguez.pdf
)
> but it seems it's not available anymore.
>
>
> I have several  *.L3m_MO_SST_4.bz2 and *.L3m_MO_CHL_chlor_a_4km.bz2 files
> obtained from
>
http://podaac.jpl.nasa.gov/dataset/MODIS_AQUA_L3_SST_THERMAL_MONTHLY_4KM_DAYTIME
> and from
http://oceandata.sci.gsfc.nasa.gov/MODISA/Mapped/Monthly/4km/chlor/
>
>
> I also have a shapefile with the boundaries of the area of interest. I'd
> like to have some statistics (maximum, minimum, mean, quantiles, ect.) of
> both variables in this area.
>
>
> Any indication of tutorials, sites or packages will be welcome.  Thanks in
> advance.
>
>
> All the best,
>
> Antônio Olinto
>
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>
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-- 
Michael Sumner
Software and Database Engineer
Australian Antarctic Division
Hobart, Australia
e-mail: mdsumner at gmail.com

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