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vips.py: VipsDataset is a GDAL-Readable VIPS modifiable image.
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Maxime Dupuis committed Nov 21, 2012
1 parent 76b9170 commit 08e177b
Showing 1 changed file with 148 additions and 119 deletions.
267 changes: 148 additions & 119 deletions gdal2mbtiles/vips.py
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Expand Up @@ -546,6 +546,139 @@ def write_to_tempfile(self, prefix='tmp', dir=None, delete=True):
return image


class VipsDataset(Dataset):
def __init__(self, inputfile, *args, **kwargs):
"""
Opens a GDAL-readable file and holds a VImage for scaling and aligning.
"""
super(VipsDataset, self).__init__(inputfile, *args, **kwargs)

self.inputfile = inputfile
self._image = None

@property
def image(self):
if self._image is None:
self._image = VImage(self.inputfile)
return self._image

def _upsample(self, ratios):
if ratios == XY(x=1.0, y=1.0):
# No upsampling needed
return

extents = self.GetExtents()
width, height = extents.dimensions

logger.debug(
'Resizing from {src_width} × {src_height} '
'to {dst_width} × {dst_height}'.format(
src_width=self.RasterXSize,
src_height=self.RasterYSize,
dst_width=int(round(self.RasterXSize * ratios.x)),
dst_height=int(round(self.RasterYSize * ratios.y))
)
)

with LibVips.disable_warnings():
self._image = self.image.stretch(xscale=ratios.x,
yscale=ratios.y)
# Fix the dataset's metadata
geotransform = list(self.GetGeoTransform())
geotransform[1] = width / self._image.Xsize() # pixel width
geotransform[5] = -height / self._image.Ysize() # pixel height
self.SetGeoTransform(geotransform, local=True)
self.SetLocalSizes(xsize=self._image.Xsize(),
ysize=self._image.Ysize())

def upsample(self, resolution=None):
"""Upsamples the image to `resolution`."""
return self._upsample(
ratios=self.GetTileScalingRatios(resolution=resolution, places=5)
)

def upsample_to_world(self):
"""Upsamples the image to native TMS resolution for the whole world."""
ratios = self.GetWorldScalingRatios()
if ratios == XY(x=1.0, y=1.0):
# No upsampling needed
return

result = self._upsample(ratios=ratios)

# Force world to be full width by changing pixel width
world = self.GetSpatialReference().GetWorldExtents()
geotransform = list(self.GetGeoTransform())
geotransform[1] = world.dimensions.x / self._image.Xsize()
self.SetGeoTransform(geotransform, local=True)

return result

def align_to_grid(self, resolution=None):
"""Aligns the image to the TMS tile grid."""
if resolution is None:
resolution = self.GetNativeResolution()
spatial_ref = self.GetSpatialReference()
pixel_sizes = spatial_ref.GetPixelDimensions(resolution=resolution)

# Assume the image is already in the right projection
extents = self.GetExtents(transform=None)
tile_extents = self.GetTiledExtents(transform=None)

left = int(round(
((extents.lower_left.x - tile_extents.lower_left.x) /
pixel_sizes.x)
))
top = int(round(
((tile_extents.upper_right.y - extents.upper_right.y) /
pixel_sizes.y)
))

width = int(tile_extents.dimensions.x / pixel_sizes.x)
height = int(tile_extents.dimensions.y / pixel_sizes.y)

if left == top == 0 and \
width == self.RasterXSize and \
height == self.RasterYSize:
# No alignment needed
return

if width % TILE_SIDE != 0:
raise AssertionError(
'width {0} is not an integer multiple of {1}'.format(
width,
TILE_SIDE
)
)
if height % TILE_SIDE != 0:
raise AssertionError(
'height {0} is not an integer multiple of {1}'.format(
height,
TILE_SIDE
)
)

logger.debug(
'Aligning within {width} × {height} at ({left}, {top})'.format(
width=width, height=height, left=left, top=top
)
)

with LibVips.disable_warnings():
self._image = self.image.embed(fill='black',
left=left, top=top,
width=width, height=height)
# Fix the dataset's metadata to match tile_extents exactly
geotransform = list(self.GetGeoTransform())
geotransform[0] = tile_extents.lower_left.x # left
geotransform[3] = tile_extents.upper_right.y # top
# pixel width and height
geotransform[1] = tile_extents.dimensions.x / self._image.Xsize()
geotransform[5] = -tile_extents.dimensions.y / self._image.Ysize()
self.SetGeoTransform(geotransform, local=True)
self.SetLocalSizes(xsize=width, ysize=height)


class TmsTiles(object):
"""Represents a set of tiles in TMS co-ordinates."""

Expand Down Expand Up @@ -768,14 +901,12 @@ def colorize(self, colors):
@property
def dataset(self):
if self._dataset is None:
self._dataset = Dataset(self.inputfile)
self._dataset = VipsDataset(self.inputfile)
return self._dataset

@property
def image(self):
if self._image is None:
self._image = VImage(self.inputfile)
return self._image
return self.dataset.image

@property
def resolution(self):
Expand Down Expand Up @@ -819,10 +950,8 @@ def slice_downsample(self, tiles, min_resolution, max_resolution=None,
)

if fill_borders or fill_borders is None:
tiles.fill_borders(
borders=self.dataset.GetWorldTmsBorders(resolution=res),
resolution=res
)
borders = self.dataset.GetWorldTmsBorders(resolution=res)
tiles.fill_borders(borders=borders, resolution=res)
tiles._slice()

# Downsample to the next layer, unless we're not going to go
Expand Down Expand Up @@ -872,10 +1001,8 @@ def slice_upsample(self, tiles, max_resolution, min_resolution=None,
)

if fill_borders or fill_borders is None:
upsampled.fill_borders(
borders=self.dataset.GetWorldTmsBorders(resolution=res),
resolution=res
)
borders = self.dataset.GetWorldTmsBorders(resolution=res)
upsampled.fill_borders(borders=borders, resolution=res)
upsampled._slice()

def slice(self, fill_borders=True):
Expand Down Expand Up @@ -912,118 +1039,20 @@ def slice(self, fill_borders=True):
# update some metadata
self.storage.post_import(pyramid=self)

def _upsample(self, ratios):
if ratios == XY(x=1.0, y=1.0):
# No upsampling needed
return

extents = self.dataset.GetExtents()
width, height = extents.dimensions

logger.debug(
'Resizing from {src_width} × {src_height} '
'to {dst_width} × {dst_height}'.format(
src_width=self.dataset.RasterXSize,
src_height=self.dataset.RasterYSize,
dst_width=int(round(self.dataset.RasterXSize * ratios.x)),
dst_height=int(round(self.dataset.RasterYSize * ratios.y))
)
)

with LibVips.disable_warnings():
self._image = self.image.stretch(xscale=ratios.x,
yscale=ratios.y)
# Fix the dataset's metadata
geotransform = list(self.dataset.GetGeoTransform())
geotransform[1] = width / self._image.Xsize() # pixel width
geotransform[5] = -height / self._image.Ysize() # pixel height
self.dataset.SetGeoTransform(geotransform, local=True)
self.dataset.SetLocalSizes(xsize=self._image.Xsize(),
ysize=self._image.Ysize())

def upsample(self, resolution=None):
"""Upsamples the image to `resolution`."""
return self._upsample(
ratios=self.dataset.GetTileScalingRatios(resolution=resolution,
places=5)
)
"""Upsamples the VIPS dataset to `resolution`."""
return self.dataset.upsample(resolution=resolution)

def upsample_to_world(self):
"""Upsamples the image to native TMS resolution for the whole world."""
ratios = self.dataset.GetWorldScalingRatios()
if ratios == XY(x=1.0, y=1.0):
# No upsampling needed
return

result = self._upsample(ratios=ratios)

# Force world to be full width by changing pixel width
world = self.dataset.GetSpatialReference().GetWorldExtents()
geotransform = list(self.dataset.GetGeoTransform())
geotransform[1] = world.dimensions.x / self._image.Xsize()
self.dataset.SetGeoTransform(geotransform, local=True)

return result
"""
Upsamples the VIPS dataset to native TMS resolution for the whole
world.
"""
return self.dataset.upsample_to_world()

def align_to_grid(self, resolution=None):
"""Aligns the image to the TMS tile grid."""
if resolution is None:
resolution = self.dataset.GetNativeResolution()
spatial_ref = self.dataset.GetSpatialReference()
pixel_sizes = spatial_ref.GetPixelDimensions(resolution=resolution)

# Assume the image is already in the right projection
extents = self.dataset.GetExtents(transform=None)
tile_extents = self.dataset.GetTiledExtents(transform=None)

left = int(round(
((extents.lower_left.x - tile_extents.lower_left.x) /
pixel_sizes.x)
))
top = int(round(
((tile_extents.upper_right.y - extents.upper_right.y) /
pixel_sizes.y)
))

width = int(tile_extents.dimensions.x / pixel_sizes.x)
height = int(tile_extents.dimensions.y / pixel_sizes.y)

if left == top == 0 and \
width == self.dataset.RasterXSize and \
height == self.dataset.RasterYSize:
# No alignment needed
return

if width % TILE_SIDE != 0:
raise AssertionError(
'width {0} is not an integer multiple of {1}'.format(width,
TILE_SIDE)
)
if height % TILE_SIDE != 0:
raise AssertionError(
'height {0} is not an integer multiple of {1}'.format(height,
TILE_SIDE)
)

logger.debug(
'Aligning within {width} × {height} at ({left}, {top})'.format(
width=width, height=height, left=left, top=top
)
)

with LibVips.disable_warnings():
self._image = self.image.embed(fill='black',
left=left, top=top,
width=width, height=height)
# Fix the dataset's metadata to match tile_extents exactly
geotransform = list(self.dataset.GetGeoTransform())
geotransform[0] = tile_extents.lower_left.x # left
geotransform[3] = tile_extents.upper_right.y # top
# pixel width and height
geotransform[1] = tile_extents.dimensions.x / self._image.Xsize()
geotransform[5] = -tile_extents.dimensions.y / self._image.Ysize()
self.dataset.SetGeoTransform(geotransform, local=True)
self.dataset.SetLocalSizes(xsize=width, ysize=height)
"""Aligns the VIPS dataset to the TMS tile grid."""
return self.dataset.align_to_grid(resolution=resolution)


def validate_resolutions(resolution,
Expand Down

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