"""
Created on Tue Apr 2 19:00:15 2013
@author: pietro
"""
from grass.pygrass.gis.region import Region
from grass.pygrass.vector.basic import Bbox
[docs]def get_bbox(reg, row, col, width, height, overlap):
"""Return a Bbox
:param reg: a Region object to split
:type reg: Region object
:param row: the number of row
:type row: int
:param col: the number of row
:type col: int
:param width: the width of tiles
:type width: int
:param height: the width of tiles
:type height: int
:param overlap: the value of overlap between tiles
:type overlap: int
"""
north = reg.north - (row * height - overlap) * reg.nsres
south = reg.north - ((row + 1) * height + overlap) * reg.nsres
east = reg.west + ((col + 1) * width + overlap) * reg.ewres
west = reg.west + (col * width - overlap) * reg.ewres
return Bbox(
north=north if north <= reg.north else reg.north,
south=south if south >= reg.south else reg.south,
east=east if east <= reg.east else reg.east,
west=west if west >= reg.west else reg.west,
)
[docs]def get_tile_start_end_row_col(reg, row, col, width, height):
"""Return a tile's starting and ending row and col
:param reg: a Region object to split
:type reg: Region object
:param row: the number of tiles in a row
:type row: int
:param col: the number of tiles in a col
:type col: int
:param width: the width of tiles
:type width: int
:param height: the width of tiles
:type height: int
"""
start_row = row * height
end_row = (row + 1) * height - 1
start_col = col * width
end_col = (col + 1) * width - 1
end_row = reg.rows - 1 if end_row >= reg.rows else end_row
end_col = reg.cols - 1 if end_col >= reg.cols else end_col
return (start_row, end_row, start_col, end_col)
[docs]def 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).
:param region: a Region object to split
:type region: Region object
:param width: the width of tiles
:type width: int
:param height: the width of tiles
:type height: int
:param overlap: the value of overlap between tiles
:type overlap: int
>>> 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
... ) # doctest: +NORMALIZE_WHITESPACE
[[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
... ) # doctest: +NORMALIZE_WHITESPACE
[[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)]]
"""
reg = region if region else Region()
ncols = (reg.cols + width - 1) // width
nrows = (reg.rows + height - 1) // height
box_list = []
# print reg
for row in range(nrows):
row_list = []
for col in range(ncols):
# print 'c', c, 'r', r
row_list.append(get_bbox(reg, row, col, width, height, overlap))
box_list.append(row_list)
return box_list
[docs]def 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).
:param region: a Region object to split
:type region: Region object
:param width: the width of tiles
:type width: int
:param height: the width of tiles
:type height: int
"""
reg = region if region else Region()
ncols = (reg.cols + width - 1) // width
nrows = (reg.rows + height - 1) // height
box_list = []
for row in range(nrows):
row_list = []
for col in range(ncols):
row_list.append(get_tile_start_end_row_col(reg, row, col, width, height))
box_list.append(row_list)
return box_list
[docs]def get_overlap_region_tiles(region=None, width=100, height=100, overlap=0):
"""Get the Bbox of the overlapped region.
:param region: a Region object to split
:type region: Region object
:param width: the width of tiles
:type width: int
:param height: the width of tiles
:type height: int
:param overlap: the value of overlap between tiles
:type overlap: int
"""
reg = region if region else Region()
ncols = (reg.cols + width - 1) // width
nrows = (reg.rows + height - 1) // height
box_list = []
# print reg
for row in range(nrows):
row_list = []
for col in range(ncols):
# print 'c', c, 'r', r
row_list.append(get_bbox(reg, row, col, width, height, -overlap))
box_list.append(row_list)
return box_list
