[R-sig-Geo] Dear Friends,

[Roger Bivand]

On Fri, 23 May 2008, Rodrigo W. Soria Auza wrote:

> Hi all,
> I have a file (MOD06_auza_gridded_cldstats.bin) created by a college (Richard 
> Frey). It is a binary written with FORTRAN in a little-endian (Linux) machine 
> that contains a 400x300x84-bite integer array.

If you have access to the Fortran source code, use readBin() to read the 
chunks. I'm puzzled by the 84 bytes, because that suggests that each cell 
record contains more than 8 8-byte double precision numbers (which would 
be 64 bytes). So you need a more detailed description than you have now.

If you read the data into pre-allocated vectors (perhaps grouped in a 
list), thes can readily be converted to a data frame. This can be 
converted into a SpatialPointsDataFrame (class defiled in the sp package) 
and further to a SpatialGridDataFrame. This can then be exported using 
writeGDAL() in the rgdal package, to a range of different formats, defined 
by the drivers in your installed GDAL, see gdalDrivers() for the ones you 
have.

Roger

> The 400 represents 1/20 degree 
> cells in a N-S direction (7S-27S), 300 is 1/20 degree cells in the E-W 
> direction (55-70W). The 8 products in order for each of the 120000 cells:
> 1) Number retrievals
> 2) Yearly mean cloud fraction
> 3) Frequency of high, thick clouds
> 4) Frequency of thick clouds top temperatures <-65C
> 5) Same as # 4 but <-38C
> 6) Same as # 4 but <-12C
> 7) Center of cell latitude
> 8) Center of cell longitude
> So as you can see is a multi layer file
> Now neither Richard (the guy who made this file) nor I know how to import 
> this kind of file into other GIS software, and I would like to know if 
> somebody here could give us detailed instructions or advise to convert layer 
> by layer into a common format (separate from each other. so we could manage 
> every layer independently from the others), so we will be able to import them 
> into other GIS software (Arcview or DIVA GIS) as raster (or grid) layers. 
> (maybe ascii?).
> I have a limited experience using R, but every day I learn a bit more and I 
> think (actually hope) there is a package that is able to do this.
> Sincerely,
> Rodrigo
>
>
>

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no