pymt.mappers package

Submodules

pymt.mappers.celltopoint module

class pymt.mappers.celltopoint.CellToPoint

Bases: IGridMapper

initialize(dest_grid, src_grid, **kwds)

Initialize the mapper to map from a source grid to a destination grid.

property name

run(src_values, **kwds)

Map values on the source grid to the destination grid.

static test(dst_grid, src_grid)

pymt.mappers.celltopoint.map_points_to_cells(coords, src_grid, src_point_ids, bad_val=-1)

pymt.mappers.esmp module

class pymt.mappers.esmp.EsmpCellToCell

Bases: EsmpMapper

init_fields()

static test(dst_grid, src_grid)

class pymt.mappers.esmp.EsmpMapper

Bases: IGridMapper

finalize()

get_dest_data()

get_dest_field()

get_source_data()

get_source_field()

init_fields()

initialize(dest_grid, src_grid, **kwds)

Initialize the mapper to map from a source grid to a destination grid.

property name

run(src_values, **kwds)

Map values on the source grid to the destination grid.

static test(dst_grid, src_grid)

class pymt.mappers.esmp.EsmpPointToPoint

Bases: EsmpMapper

init_fields()

static test(dst_grid, src_grid)

pymt.mappers.imapper module

class pymt.mappers.imapper.IGridMapper

Bases: object

Interface for a grid mapper.

initialize(dest_grid, src_grid, **kwds)

Initialize the mapper to map from a source grid to a destination grid.

run(src_values, **kwds)

Map values on the source grid to the destination grid.

exception pymt.mappers.imapper.IncompatibleGridError(dst, src)

Bases: MapperError

Error to indicate that the source grid cannot be mapped to the destination.

exception pymt.mappers.imapper.MapperError

Bases: Exception

Base class for error in this package.

exception pymt.mappers.imapper.NoMapperError(dst, src)

Bases: MapperError

pymt.mappers.mapper module

Examples

Point-to-point Mapping

>>> import numpy as np
>>> from pymt.grids.map import RectilinearMap as Rectilinear

>>> src = Rectilinear([0, 1, 2], [0, 2])
>>> dst = Rectilinear([.5, 1.5, 2.5], [.25, 1.25])

>>> src.get_x()
array([ 0.,  2.,  0.,  2.,  0.,  2.])

>>> src.get_y()
array([ 0.,  0.,  1.,  1.,  2.,  2.])

>>> dst.get_x()
array([ 0.25,  1.25,  0.25,  1.25,  0.25,  1.25])
>>> dst.get_y()
array([ 0.5,  0.5,  1.5,  1.5,  2.5,  2.5])

>>> src_vals = np.arange(src.get_point_count(), dtype=np.float64)

Map the source values on the source points to the destination grid using nearest neighbor.

>>> from pymt.mappers import NearestVal

>>> mapper = NearestVal()
>>> mapper.initialize(dst, src)
>>> mapper.run(src_vals)
array([ 0.,  1.,  2.,  3.,  4.,  5.])

>>> mappers = find_mapper(dst, src)
>>> len(mappers)
3
>>> mappers[0].name
'PointToPoint'

>>> src_vals[2] = -999
>>> dst_vals = np.full(dst.get_point_count(), -1.)
>>> mapper.run(src_vals, dst_vals=dst_vals)
array([ 0.,  1., -1.,  3.,  4.,  5.])

Cell-to-point Mapping

The source grid looks like,

(0) ------ (1)
 |          |
 |          |
(2) ------ (3)
 |          |
 |          |
(4) ------ (5)
 |          |
 |          |
(7) ------ (7)

>>> from pymt.mappers import CellToPoint
>>> from pymt.grids.map import UniformRectilinearMap as UniformRectilinear
>>> from pymt.grids.map import UnstructuredPointsMap as UnstructuredPoints

>>> (dst_x, dst_y) = (np.array([.45, 1.25, 3.5]), np.array([.75, 2.25, 3.25]))

>>> src = UniformRectilinear((2,4), (2, 1), (0, 0))
>>> dst = UnstructuredPoints(dst_x, dst_y)

>>> src_vals = np.arange(src.get_cell_count(), dtype=np.float64)

>>> mapper = CellToPoint()
>>> mapper.initialize(dst, src)
>>> mapper.run(src_vals, bad_val=-999)
array([   0.,    2., -999.])

>>> src_vals = np.arange(src.get_cell_count(), dtype=np.float64)
>>> src_vals[0] = -9999
>>> dst_vals = np.zeros(dst.get_point_count()) + 100
>>> _ = mapper.run(src_vals, dst_vals=dst_vals)
>>> dst_vals
array([ 100.,    2., -999.])

Point-to-cell Mapping

>>> from pymt.mappers.pointtocell import PointToCell
>>> (src_x, src_y) = (np.array ([.45, 1.25, 3.5, .0, 1.]),
...                   np.array ([.75, 2.25, 3.25, .9, 1.1]))

>>> src = UnstructuredPoints(src_x, src_y)
>>> dst = UniformRectilinear((2,4), (2, 1), (0, 0))

>>> src_vals = np.arange(src.get_point_count(), dtype=np.float64)

>>> mapper = PointToCell()
>>> mapper.initialize(dst, src)

>>> mapper.run(src_vals, bad_val=-999)
array([ 1.5,  4. ,  1. ])

>>> mapper.run(src_vals, bad_val=-999, method=np.sum)
array([ 3.,  4.,  1.])

>>> src_vals[0] = -9999
>>> dst_vals = np.zeros(dst.get_cell_count ()) - 1
>>> _ = mapper.run(src_vals, dst_vals=dst_vals)
>>> dst_vals
array([-1.,  4.,  1.])

Point on cell edges

>>> (src_x, src_y) = (np.array ([0, .5, 1., 2, 3.5]),
...                   np.array ([1., 1., .0, 3, 3.]))
>>> src = UnstructuredPoints(src_x, src_y)
>>> dst = UniformRectilinear((2,4), (2, 1), (0, 0))

>>> mapper = PointToCell()
>>> mapper.initialize(dst, src)

>>> src_vals = np.arange(src.get_point_count(), dtype=np.float64)
>>> dst_vals = np.zeros(dst.get_cell_count()) - 1
>>> _ = mapper.run(src_vals, dst_vals=dst_vals)
>>> dst_vals
array([ 1. ,  0.5,  3. ])

A big mapper

>>> (m, n) = (20, 40)
>>> (src_x, src_y) = np.meshgrid(range(m), range(n))
>>> src = UnstructuredPoints(src_y, src_x)
>>> dst = UniformRectilinear((n + 1, m + 1), (1, 1), (-.5, -.5))

>>> mapper = PointToCell()
>>> mapper.initialize(dst, src)

>>> src_vals = np.arange(src.get_point_count(), dtype=np.float64)
>>> dst_vals = np.zeros(dst.get_cell_count(), dtype=np.float64) - 1
>>> _ = mapper.run(src_vals, dst_vals=dst_vals)

>>> from numpy.testing import assert_array_equal
>>> assert_array_equal(dst_vals, src_vals)

pymt.mappers.mapper.find_mapper(dst_grid, src_grid)

Find appropriate mappers to map bewteen two grid-like objects

pymt.mappers.pointtocell module

class pymt.mappers.pointtocell.PointToCell

Bases: IGridMapper

initialize(dest_grid, src_grid, **kwds)

Initialize the mapper to map from a source grid to a destination grid.

property name

run(src_values, **kwds)

Map values on the source grid to the destination grid.

static test(dst_grid, src_grid)

pymt.mappers.pointtocell.map_cells_to_points(coords, dst_grid, dst_point_ids, bad_val=-1)

pymt.mappers.pointtopoint module

class pymt.mappers.pointtopoint.NearestVal

Bases: IGridMapper

Examples

>>> import numpy as np
>>> from pymt.grids.map import RectilinearMap
>>> from pymt.mappers.pointtopoint import NearestVal
>>> src = RectilinearMap([0, 1, 2], [0, 2])
>>> dst = RectilinearMap([.25, 1.25, 2.25], [.25, 1.25])
>>> mapper = NearestVal()
>>> mapper.initialize(dst, src)
>>> mapper.run(np.arange(6.))
array([ 0.,  1.,  2.,  3.,  4.,  5.])

initialize(dest_grid, src_grid, **kwds)

Map points on one grid to the nearest points on another.

Parameters:

• dest_grid (grid_like) – Grid onto which points are mapped

• src_grid (grid_like) – Grid from which points are taken.

• var_names (iterable of tuples (optional)) – Iterable of (dest, src) variable names.

property name

Name of the grid mapper.

run(src_values, **kwds)

Map source values onto destination values.

Parameters:

• src_values (ndarray) – Source values at points.

• dst_vals (ndarray (optional)) – Destination array to put mapped values.

Returns:

dest – The (possibly newly-created) destination array.

Return type:

ndarray

static test(dst_grid, src_grid)

Test if grids are compatible with this mapper.

Parameters:

• dst_grid (grid_like) – Grid onto which points are mapped

• src_grid (grid_like) – Grid from which points are taken.

pymt.mappers.pointtopoint.copy_good_values(src, dst, bad_val=-999)

Copy only the good values from one array to another.

Parameters:

• src (array_like) – Array of source values.

• dst (array_like) – Array into which to copy the good values.

• bad_val (float (optional)) – Value below which indicates a bad value.

Returns:

dst – The destination array.

Return type:

array_like

Examples

>>> import numpy as np
>>> from pymt.mappers.pointtopoint import copy_good_values
>>> x = np.arange(6)
>>> y = np.zeros((2, 3))
>>> rv = copy_good_values(x, y)
>>> rv is y
True
>>> y
array([[ 0.,  1.,  2.],
       [ 3.,  4.,  5.]])
>>> copy_good_values(x, np.zeros(6), bad_val=3.)
array([ 0.,  0.,  0.,  0.,  4.,  5.])

Module contents

class pymt.mappers.CellToPoint

Bases: IGridMapper

initialize(dest_grid, src_grid, **kwds)

Initialize the mapper to map from a source grid to a destination grid.

property name

run(src_values, **kwds)

Map values on the source grid to the destination grid.

static test(dst_grid, src_grid)

exception pymt.mappers.IncompatibleGridError(dst, src)

Bases: MapperError

Error to indicate that the source grid cannot be mapped to the destination.

class pymt.mappers.NearestVal

Bases: IGridMapper

Examples

>>> import numpy as np
>>> from pymt.grids.map import RectilinearMap
>>> from pymt.mappers.pointtopoint import NearestVal
>>> src = RectilinearMap([0, 1, 2], [0, 2])
>>> dst = RectilinearMap([.25, 1.25, 2.25], [.25, 1.25])
>>> mapper = NearestVal()
>>> mapper.initialize(dst, src)
>>> mapper.run(np.arange(6.))
array([ 0.,  1.,  2.,  3.,  4.,  5.])

initialize(dest_grid, src_grid, **kwds)

Map points on one grid to the nearest points on another.

Parameters:

• dest_grid (grid_like) – Grid onto which points are mapped

• src_grid (grid_like) – Grid from which points are taken.

• var_names (iterable of tuples (optional)) – Iterable of (dest, src) variable names.

property name

Name of the grid mapper.

run(src_values, **kwds)

Map source values onto destination values.

Parameters:

• src_values (ndarray) – Source values at points.

• dst_vals (ndarray (optional)) – Destination array to put mapped values.

Returns:

dest – The (possibly newly-created) destination array.

Return type:

ndarray

static test(dst_grid, src_grid)

Test if grids are compatible with this mapper.

Parameters:

• dst_grid (grid_like) – Grid onto which points are mapped

• src_grid (grid_like) – Grid from which points are taken.

class pymt.mappers.PointToCell

Bases: IGridMapper

initialize(dest_grid, src_grid, **kwds)

Initialize the mapper to map from a source grid to a destination grid.

property name

run(src_values, **kwds)

Map values on the source grid to the destination grid.

static test(dst_grid, src_grid)

pymt.mappers.find_mapper(dst_grid, src_grid)

Find appropriate mappers to map bewteen two grid-like objects