const_stride.rst

tiling.const_stride

tiling.const_stride

Class provides tile parameters (offset, extent) to extract data from image.

Generated tile extents starts from an origin, has constant stride and can optionally include nodata paddings. For example, tiling can look like this (origin is negative, include nodata)

tile 0        tile 2      tile 4
|<------->|   |<------>|  |<------>|     etc
          tile 1      tile 3      tile 5     tile n-1
^      |<------->|  |<------>|  |<------>| |<------>|
|        |<------------------------------------>|

origin | IMAGE |

                                     |

Another example, tiling can look like this (origin is negative, no nodata, tile size is not constant at boundaries)

tile 0    tile 2      tile 4
|<->|   |<------>|  |<------>|     etc
  tile 1      tile 3      tile 5     tile n-1

^ |

origin | IMAGE |

                                     |

Another example, tiling can look like this (origin is postive, no nodata, tile size is not constant at boundaries)

tile 0        tile 2

etc

tile 1 tile 3 tile n-1

^

| | IMAGE | | origin |

Basic usage:

from tiling import ConstStrideTiles

tiles = ConstStrideTiles(image_size=(500, 500), tile_size=(256, 256), stride=(100, 100))

print("Number of tiles: %i" % len(tiles))
for (x, y, width, height), (out_width, out_height) in tiles:
    data = read_data(x, y, width, height, out_width, out_height)
    print("data.shape: {}".format(data.shape))

# Get a tile params at linear index:
extent, out_size = tiles[len(tiles)//2]

ConstStrideTiles