[R-sig-Geo] gpc cloud data files

[Barry Rowlingson]

On Mon, Mar 1, 2010 at 6:06 PM, ogbos okike <ogbos.okike at gmail.com> wrote:
> Happy New Year.
>
> I have some cloud data files (e.g. ISCCP.D2.0.GLOBAL.1983.07.99.0000.GPC)
> and wish to analyze them in R. This is my first time of encountering this
> sort of file. I have searched for .gpc files in R and understand that gpclib
> package may be a way out. However, I need a hint to start from somewhere.
>
> I would be most grateful if anybody could give me a tip.

 What do you expect it to be? Gridded raster data or vector polygon
outlines? Or points? The GPC documentation only mentions one file
format, a text-based one that looks like this
[http://www.cs.man.ac.uk/~toby/alan/software/gpc.html]

"""
For example, a single polygon consisting of a triangular hole within a
quadrilateral (with hole flags included) may take the form:
          2
          3
          1
            4.0   4.0
            6.0   5.0
            5.0   6.0
          4
          0
            2.0   1.0
            8.0   2.0
            7.0   9.0
            1.0   7.0
"""

 Do your files look like that when you open them in a text editor?

 Or tell us where you got them from if we can download them ourselves,
we'll have a better chance of helping!

Barry


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