The hgrib package

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Unofficial bindings to ECMWF's GRIB API library for reading WMO FM-92 GRIB edition 1 and edition 2 messages.


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Properties

Versions0.1.0.0, 0.2.0.0, 0.2.0.0, 0.3.0.0, 0.3.1.0
Change logCHANGELOG.md
Dependenciesbase (>=4.5 && <4.9), hgrib [details]
LicenseGPL-3
Copyright(c) 2015 Mattias Jakobsson
AuthorMattias Jakobsson
Maintainermjakob422@gmail.com
CategoryData
Home pagehttps://github.com/mjakob/hgrib
Bug trackerhttps://github.com/mjakob/hgrib/issues
Source repositoryhead: git clone https://github.com/mjakob/hgrib.git -b develop
this: git clone https://github.com/mjakob/hgrib.git(tag 0.2.0.0)
Executablesget
UploadedMon Sep 7 08:46:42 UTC 2015 by mjakob

Modules

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Flags

NameDescriptionDefaultType
build_examples

Build GRIB API example programs

DisabledManual

Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info

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For package maintainers and hackage trustees


Readme for hgrib-0.2.0.0

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HGrib

Build Status

Unofficial bindings for ECMWF's GRIB API library for reading WMO FM-92 GRIB edition 1 and edition 2 messages.

In this version of HGrib, raw bindings for the documented part of GRIB API is available. Future versions are intended to include a higher-level Haskell interface.

Installation

The following prerequisites are needed to build HGrib:

With these requirements available, HGrib can be installed from Hackage with Cabal:

cabal install hgrib

Usage

Right now, only raw bindings for the documented part of GRIB API is available in Data.Grib.Raw. Much of the documentation is copied into HGrib's reference documentation generated by Haddock. To be able to work with these bindings, bindings for C's fopen is provided in Data.Grib.Raw.CFile (which is re-exported by Data.Grib.Raw). An example of usage is GRIB API's get.c example re-written with HGrib's bindings:

import Control.Exception (assert)
import Data.Grib.Raw
import Foreign           (allocaArray, allocaBytes)
import Text.Printf       (printf)


filename :: FilePath
filename = "test/stage/regular_latlon_surface.grib1"

assertIO :: Bool -> IO ()
assertIO = flip assert $ return ()

main :: IO ()
main = do
  h <- withBinaryCFile filename ReadMode $
         gribHandleNewFromFile defaultGribContext

  _ <- gribSetString h "file" filename

  gribGetLong h "Ni" >>= printf "numberOfPointsAlongAParallel=%d\n"
  gribGetLong h "Nj" >>= printf "numberOfPointsAlongAMeridian=%d\n"

  gribGetDouble h "yFirst" >>= printf "latitudeOfFirstGridPointInDegrees=%g\n"
  gribGetDouble h "xFirst" >>= printf "longitudeOfFirstGridPointInDegrees=%g\n"
  gribGetDouble h "yLast"  >>= printf "latitudeOfLastGridPointInDegrees=%g\n"
  gribGetDouble h "xLast"  >>= printf "longitudeOfLastGridPointInDegrees=%g\n"
  gribGetDouble h "DyInDegrees" >>= printf "jDirectionIncrementInDegrees=%g\n"
  gribGetDouble h "DxInDegrees" >>= printf "iDirectionIncrementInDegrees=%g\n"

  len <- gribGetLength h "packingType"
  allocaBytes len $ \bufr -> do
    packingType <- gribGetString h "packingType" bufr len
    printf "packingType=%s (%d)\n" packingType (length packingType + 1)

  size <- gribGetSize h "values"
  allocaArray size $ \array -> do
    values <- gribGetDoubleArray h "values" array size
    let average = sum values / (fromIntegral . length $ values)
    printf "There are %d values, average is %g\n" size average

  len' <- gribGetLength h "file"
  assertIO $ len' == 1 + length filename
  allocaBytes len' $ \bufr' -> do
    file <- gribGetString h "file" bufr' len'
    assertIO $ file == filename

Contributing

Issues and pull requests are most welcome! In particular, let me know if there is any undocumented part of GRIB API that you would like to have included.

Licenses

HGrib was created and is currently maintained by Mattias Jakobsson. It is released under the GNU General Public License v3.0. ECMWF's GRIB API is released under the Apache license. HGrib is in no way associated with ECMWF or the original library.