| Copyright | (c) Mattias Jakobsson 2015 |
|---|---|
| License | GPL-3 |
| Maintainer | mjakob422@gmail.com |
| Stability | unstable |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell2010 |
Data.Grib.Raw.Nearest
Description
Find the nearest grid points of an arbitrary point.
Most of the documentation herein was copied from the official documentation of grib_api.
- newtype GribNearest = GribNearest (Ptr GribNearest)
- gribNearestNew :: GribHandle -> IO GribNearest
- gribNearestFind :: GribNearest -> GribHandle -> Double -> Double -> [GribNearestFlag] -> IO ([Double], [Double], [Double], [Double], [Int])
- gribNearestFindMultiple :: GribHandle -> Bool -> [Double] -> [Double] -> IO ([Double], [Double], [Double], [Double], [Int])
- gribNearestDelete :: GribNearest -> IO ()
- withGribNearest :: GribHandle -> (GribNearest -> IO a) -> IO a
- data GribNearestFlag
The GRIB Nearest Iterator
newtype GribNearest Source
Grib nearest, structure used to find the nearest points of a latitude longitude point.
Constructors
| GribNearest (Ptr GribNearest) |
Instances
gribNearestNew :: GribHandle -> IO GribNearest Source
Create a new nearest from a handle, using current geometry.
The returned object needs to be manually deleted with
gribNearestDelete. This is handled automatically by
withGribNearest.
gribNearestFind :: GribNearest -> GribHandle -> Double -> Double -> [GribNearestFlag] -> IO ([Double], [Double], [Double], [Double], [Int]) Source
Find the 4 nearest points of a latitude longitude point.
The flags are provided to speed up the process of searching. If you are sure that the point you are asking for is not changing from a call to another you can use GRIB_NEAREST_SAME_POINT. The same is valid for the grid. Flags can be used together doing a bitwise OR. The distances are given in kilometres.
gribNearestFindMultiple Source
Arguments
| :: GribHandle | handle from which geography and data values are taken |
| -> Bool | lsm flag ( |
| -> [Double] | latitudes of the points to search for |
| -> [Double] | longitudes of the points to search for |
| -> IO ([Double], [Double], [Double], [Double], [Int]) | an IO action that will return a tuple
|
Find the nearest point of a set of points whose latitudes and longitudes are given in the inlats, inlons arrays respectively.
If the flag is_lsm is 1 the nearest land point is returned and the grib passed as handle (h) is considered a land sea mask. The land nearest point is the nearest point with land sea mask value>=0.5. If no nearest land points are found the nearest value is returned. If the flag is_lsm is 0 the nearest point is returned. values, distances, indexes (in the "values" array) for the nearest points (ilons,ilats) are returned.
gribNearestDelete :: GribNearest -> IO () Source
Frees an nearest from memory.
withGribNearest :: GribHandle -> (GribNearest -> IO a) -> IO a Source
Safely create, use and delete a GribNearest.
This function is an easy alternative over using gribNearestNew
and gribNearestDelete directly.
Nearest flags
data GribNearestFlag Source
Filter flags for GribNearest.