In this version of HGrib, a read-only monadic Haskell interface to GRIB API is provided. Raw bindings for the documented parts of GRIB API are also available. Future versions are intended to expand the higher-level Haskell interface to include, among other things, write support.
The following prerequisites are needed to build HGrib:
GRIB API >= 1.12 installed and discoverable by ghc (use cabal's
--extra-lib-dirsif it's installed at a custom location); and
Haskell base >= 4.5; and
c2hs == 0.26.*.
cabal install hgrib
HGrib provides a high-level monadic Haskell interface to GRIB API in
Data.Grib. An example of its usage is GRIB API's get.c
example re-written with HGrib:
import Control.Exception ( assert ) import Data.Grib import Text.Printf ( printf ) main :: IO () main = let filename = "test/stage/regular_latlon_surface.grib1" in runGribIO_ filename $ do setString "file" filename getLong "Ni" >>= liftIO . printf "numberOfPointsAlongAParallel=%d\n" getLong "Nj" >>= liftIO . printf "numberOfPointsAlongAMeridian=%d\n" getDouble "yFirst" >>= liftIO . printf "latitudeOfFirstGridPointInDegrees=%g\n" getDouble "xFirst" >>= liftIO . printf "longitudeOfFirstGridPointInDegrees=%g\n" getDouble "yLast" >>= liftIO . printf "latitudeOfLastGridPointInDegrees=%g\n" getDouble "xLast" >>= liftIO . printf "longitudeOfLastGridPointInDegrees=%g\n" getDouble "DyInDegrees" >>= liftIO . printf "jDirectionIncrementInDegrees=%g\n" getDouble "DxInDegrees" >>= liftIO . printf "iDirectionIncrementInDegrees=%g\n" getString "packingType" >>= liftIO . printf "packingType=%s\n" values <- getValues let numValues = length values average = sum values / fromIntegral numValues liftIO $ printf "There are %d values, average is %g\n" numValues average filename' <- getString "file" liftIO $ assert (filename' == filename) (return ())
Raw bindings for the documented part of GRIB API is also
Data.Grib.Raw. To be able to work with these bindings,
bindings for C's
fopen is provided in
is re-exported by
Issues, feature and pull requests are most welcome! In particular, please give suggestions on what you would like to see in the higher-level interface and let me know if there is any undocumented part of GRIB API that you would like to have included.
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.