pygrass.modules.grid package

Submodules

pygrass.modules.grid.grid module

class pygrass.modules.grid.grid.GridModule(cmd, width=None, height=None, overlap=0, processes=None, split=False, debug=False, region=None, move=None, log=False, start_row=0, start_col=0, out_prefix='', mapset_prefix=None, patch_backend=None, *args, **kargs)

Bases: object

Run GRASS raster commands in a multiprocessing mode.

Parameters

• cmd (str) – raster GRASS command, only command staring with r.* are valid.

• width (int) – width of the tile, in pixel

• height (int) – height of the tile, in pixel.

• overlap (int) – overlap between tiles, in pixel.

• processes – number of threads, default value is equal to the number of processor available.

• split (bool) – if True use r.tile to split all the inputs.

• mapset_prefix (str) – if specified created mapsets start with this prefix

• patch_backend (None or str) – “r.patch”, “RasterRow”, or None for for default

• run (bool) – if False only instantiate the object

• args – give all the parameters to the command

• kargs – give all the parameters to the command

When patch_backend is None, the RasterRow method is used for patching the result. When patch_backend is “r.patch”, r.patch is used with nprocs=processes. r.patch can only be used when overlap is 0.

>>> grd = GridModule('r.slope.aspect',
...                  width=500, height=500, overlap=2,
...                  processes=None, split=False,
...                  elevation='elevation',
...                  slope='slope', aspect='aspect', overwrite=True)
>>> grd.run()

Temporary mapsets created start with a generated prefix which is unique for each process (includes PID and node name). If more instances of this class are used in parallel from one process with the same module, a custom mapset_prefix needs to be provided.

clean_location(location=None)

Remove all created mapsets.

Parameters

location (Location object) – a Location instance where we are running the analysis

define_mapset_inputs()

Add the mapset information to the input maps

estimate_tile_size()

Estimates tile width and height based on number of processes.

Keeps width and height if provided by user. If one dimension is provided the other is computed as the minimum number of tiles to keep all requested processes working (initially). If no dimensions are provided, tiling is 1 column x N rows which speeds up patching.

get_works()

Return a list of tuble with the parameters for cmd_exe function

patch()

Patch the final results.

rm_tiles()

Remove all the tiles.

run(patch=True, clean=True)

Run the GRASS command

Parameters

• patch (bool) – set False if you does not want to patch the results

• clean (bool) – set False if you does not want to remove all the stuff created by GridModule

split()

Split all the raster inputs using r.tile

pygrass.modules.grid.grid.cmd_exe(args)

Create a mapset, and execute a cmd inside.

Parameters

args (tuple) – is a tuple that contains several information see below

Returns

None

The puple has to contain:

• bbox (dict): a dict with the region parameters (n, s, e, w, etc.) that we want to set before to apply the command.

• mapnames (dict): a dictionary to substitute the input if the domain has been split in several tiles.

• gisrc_src (str): path of the GISRC file from where we want to copy the groups.

• gisrc_dst (str): path of the GISRC file where the groups will be created.

• cmd (dict): a dictionary with all the parameter of a GRASS module.

• groups (list): a list of strings with the groups that we want to copy in the mapset.

pygrass.modules.grid.grid.copy_groups(groups, gisrc_src, gisrc_dst, region=None)

Copy group from one mapset to another, crop the raster to the region

Parameters

• groups (list of strings) – a list of strings with the group that must be copied from a master to another.

• gisrc_src (str) – path of the GISRC file from where we want to copy the groups

• gisrc_dst (str) – path of the GISRC file where the groups will be created

• region (Region object or dictionary) – a region like object or a dictionary with the region parameters that will be used to crop the rasters of the groups

Returns

None

pygrass.modules.grid.grid.copy_mapset(mapset, path)

Copy mapset to another place without copying raster and vector data.

Parameters

• mapset (Mapset object) – a Mapset instance to copy

• path (str) – path where the new mapset must be copied

Returns

the instance of the new Mapset.

>>> from grass.script.core import gisenv
>>> mname = gisenv()['MAPSET']
>>> mset = Mapset()
>>> mset.name == mname
True
>>> import tempfile as tmp
>>> import os
>>> path = os.path.join(tmp.gettempdir(), 'my_loc', 'my_mset')
>>> copy_mapset(mset, path)                           
Mapset(...)
>>> sorted(os.listdir(path))                          
[...'PERMANENT'...]
>>> sorted(os.listdir(os.path.join(path, 'PERMANENT')))
['DEFAULT_WIND', 'PROJ_INFO', 'PROJ_UNITS', 'VAR', 'WIND']
>>> sorted(os.listdir(os.path.join(path, mname)))   
[...'WIND'...]
>>> import shutil
>>> shutil.rmtree(path)

pygrass.modules.grid.grid.copy_rasters(rasters, gisrc_src, gisrc_dst, region=None)

Copy rasters from one mapset to another, crop the raster to the region.

Parameters

• rasters (list) – a list of strings with the raster map that must be copied from a master to another.

• gisrc_src (str) – path of the GISRC file from where we want to copy the groups

• gisrc_dst (str) – path of the GISRC file where the groups will be created

• region (Region object or dictionary) – a region like object or a dictionary with the region parameters that will be used to crop the rasters of the groups

Returns

None

pygrass.modules.grid.grid.copy_special_mapset_files(path_src, path_dst)

Copy all the special GRASS files that are contained in a mapset to another mapset

Parameters

• path_src (str) – the path to the original mapset

• path_dst (str) – the path to the new mapset

pygrass.modules.grid.grid.copy_vectors(vectors, gisrc_src, gisrc_dst)

Copy vectors from one mapset to another, crop the raster to the region.

Parameters

• vectors (list) – a list of strings with the vector map that must be copied from a master to another.

• gisrc_src (str) – path of the GISRC file from where we want to copy the groups

• gisrc_dst (str) – path of the GISRC file where the groups will be created

Returns

None

pygrass.modules.grid.grid.get_cmd(cmdd)

Transform a cmd dictionary to a list of parameters. It is useful to pickle a Module class and cnvert into a string that can be used with Popen(get_cmd(cmdd), shell=True).

Parameters

cmdd (dict) – a module dictionary with all the parameters

>>> slp = Module('r.slope.aspect',
...              elevation='ele', slope='slp', aspect='asp',
...              overwrite=True, run_=False)
>>> get_cmd(slp.get_dict())  
['r.slope.aspect', 'elevation=ele', 'format=degrees', ..., '--o']

pygrass.modules.grid.grid.get_mapset(gisrc_src, gisrc_dst)

Get mapset from a GISRC source to a GISRC destination.

Parameters

• gisrc_src (str) – path to the GISRC source

• gisrc_dst (str) – path to the GISRC destination

Returns

a tuple with Mapset(src), Mapset(dst)

pygrass.modules.grid.grid.read_gisrc(gisrc)

Read a GISRC file and return a tuple with the mapset, location and gisdbase.

Parameters

gisrc (str) – the path to GISRC file

Returns

a tuple with the mapset, location and gisdbase

>>> import os
>>> from grass.script.core import gisenv
>>> genv = gisenv()
>>> (read_gisrc(os.environ['GISRC']) == (genv['MAPSET'],
...                                      genv['LOCATION_NAME'],
...                                      genv['GISDBASE']))
True

pygrass.modules.grid.grid.select(parms, ptype)

Select only a certain type of parameters.

Parameters

• parms (DictType parameters) – a DictType parameter with inputs or outputs of a Module class

• ptype (str) – String define the type of parameter that we want to select, valid ptype are: ‘raster’, ‘vector’, ‘group’

Returns

An iterator with the value of the parameter.

>>> slp = Module('r.slope.aspect',
...              elevation='ele', slope='slp', aspect='asp',
...              run_=False)
>>> for rast in select(slp.outputs, 'raster'):
...     print(rast)
...
slp
asp

pygrass.modules.grid.grid.set_region(region, gisrc_src, gisrc_dst, env)

Set a region into two different mapsets.

Parameters

• region (Region object or dictionary) – a region like object or a dictionary with the region parameters that will be used to crop the rasters of the groups

• gisrc_src (str) – path of the GISRC file from where we want to copy the groups

• gisrc_dst (str) – path of the GISRC file where the groups will be created

• env –

Returns

None

pygrass.modules.grid.patch module

Created on Tue Apr 2 18:57:42 2013

@author: pietro

pygrass.modules.grid.patch.get_start_end_index(bbox_list)

Convert a Bounding Box to a list of the index of column start, end, row start and end :param bbox_list: a list of BBox object to convert :type bbox_list: list of BBox object

Deprecated since version 8.3.

pygrass.modules.grid.patch.rpatch_map(raster, mapset, mset_str, bbox_list, overwrite=False, start_row=0, start_col=0, prefix='')

Patch raster using a bounding box list to trim the raster.

Parameters

• raster (str) – the name of output raster

• mapset (str) – the name of mapset to use

• mset_str (str) –

• bbox_list (list of BBox object) – a list of BBox object to convert

• overwrite (bool) – overwrite existing raster

• start_row (int) – the starting row of original raster

• start_col (int) – the starting column of original raster

• prefix (str) – the prefix of output raster

pygrass.modules.grid.patch.rpatch_map_r_patch_backend(raster, mset_str, bbox_list, overwrite=False, start_row=0, start_col=0, prefix='', processes=1)

Patch raster using a r.patch. Only use with overlap=0. Will be faster than rpatch_map, since r.patch is parallelized.

Parameters

• raster (str) – the name of output raster

• mset_str (str) –

• bbox_list (list of BBox object) – a list of BBox object to convert

• overwrite (bool) – overwrite existing raster

• start_row (int) – the starting row of original raster

• start_col (int) – the starting column of original raster

• prefix (str) – the prefix of output raster

• processes (int) – number of parallel process for r.patch

pygrass.modules.grid.patch.rpatch_row(rast, rasts, bboxes)

Patch a row of bound boxes.

Parameters

• rast (Raster object) – a Raster object to write

• rasts (list of Raster object) – a list of Raster object to read

• bboxes (list of BBox object) – a list of BBox object

pygrass.modules.grid.split module

Created on Tue Apr 2 19:00:15 2013

@author: pietro

pygrass.modules.grid.split.get_bbox(reg, row, col, width, height, overlap)

Return a Bbox

Parameters

• reg (Region object) – a Region object to split

• row (int) – the number of row

• col (int) – the number of row

• width (int) – the width of tiles

• height (int) – the width of tiles

• overlap (int) – the value of overlap between tiles

pygrass.modules.grid.split.get_overlap_region_tiles(region=None, width=100, height=100, overlap=0)

Get the Bbox of the overlapped region.

Parameters

• region (Region object) – a Region object to split

• width (int) – the width of tiles

• height (int) – the width of tiles

• overlap (int) – the value of overlap between tiles

pygrass.modules.grid.split.get_tile_start_end_row_col(reg, row, col, width, height)

Return a tile’s starting and ending row and col

Parameters

• reg (Region object) – a Region object to split

• row (int) – the number of tiles in a row

• col (int) – the number of tiles in a col

• width (int) – the width of tiles

• height (int) – the width of tiles

pygrass.modules.grid.split.split_region_in_overlapping_tiles(region=None, width=100, height=100, overlap=0)

Split a region into a list of overlapping tiles defined as (N, S, E, W).

Parameters

• region (Region object) – a Region object to split

• width (int) – the width of tiles

• height (int) – the width of tiles

• overlap (int) – the value of overlap between tiles

>>> reg = Region()
>>> reg.north = 1350
>>> reg.south = 0
>>> reg.nsres = 1
>>> reg.east = 1500
>>> reg.west = 0
>>> reg.ewres = 1
>>> reg.cols
1500
>>> reg.rows
1350
>>> split_region_in_overlapping_tiles(region=reg, width=1000, height=700, overlap=0) 
[[Bbox(1350.0, 650.0, 1000.0, 0.0), Bbox(1350.0, 650.0, 1500.0, 1000.0)],
 [Bbox(650.0, 0.0, 1000.0, 0.0), Bbox(650.0, 0.0, 1500.0, 1000.0)]]
>>> split_region_in_overlapping_tiles(region=reg, width=1000, height=700, overlap=10) 
[[Bbox(1350.0, 640.0, 1010.0, 0.0), Bbox(1350.0, 640.0, 1500.0, 990.0)],
 [Bbox(660.0, 0.0, 1010.0, 0.0), Bbox(660.0, 0.0, 1500.0, 990.0)]]

pygrass.modules.grid.split.split_region_tiles(region=None, width=100, height=100)

Split a region into a list of tiles defined as (start_row, end_row, start_col, end_col).

Parameters

• region (Region object) – a Region object to split

• width (int) – the width of tiles

• height (int) – the width of tiles

Module contents