def get_zooms(
src_dst,
tilesize: int = 256,
tms: morecantile.TileMatrixSet = morecantile.tms.get("WebMercatorQuad"),
zoom_level_strategy: str = "auto",
) -> Tuple[int, int]:
"""Calculate raster min/max zoom level."""
if src_dst.crs != tms.crs:
aff, w, h = calculate_default_transform(
src_dst.crs,
tms.crs,
src_dst.width,
src_dst.height,
*src_dst.bounds,
)
else:
aff = list(src_dst.transform)
w = src_dst.width
h = src_dst.height
resolution = max(abs(aff[0]), abs(aff[4]))
max_zoom = tms.zoom_for_res(
resolution,
max_z=30,
zoom_level_strategy=zoom_level_strategy,
)
overview_level = get_maximum_overview_level(w, h, minsize=tilesize)
ovr_resolution = resolution * (2**overview_level)
min_zoom = tms.zoom_for_res(ovr_resolution, max_z=30)
return (min_zoom, max_zoom)
def get_web_optimized_params(
src_dst,
zoom_level_strategy: str = "auto",
zoom_level: Optional[int] = None,
aligned_levels: Optional[int] = None,
tms: morecantile.TileMatrixSet = morecantile.tms.get("WebMercatorQuad"),
) -> Dict:
"""Return VRT parameters for a WebOptimized COG."""
if src_dst.crs != tms.rasterio_crs:
with WarpedVRT(src_dst, crs=tms.rasterio_crs) as vrt:
bounds = vrt.bounds
aff = list(vrt.transform)
else:
bounds = src_dst.bounds
aff = list(src_dst.transform)
resolution = max(abs(aff[0]), abs(aff[4]))
if zoom_level is None:
# find max zoom (closest to the raster resolution)
max_zoom = tms.zoom_for_res(
resolution,
max_z=30,
zoom_level_strategy=zoom_level_strategy,
)
else:
max_zoom = zoom_level
# defined the zoom level we want to align the raster
aligned_levels = aligned_levels or 0
base_zoom = max_zoom - aligned_levels
# find new raster bounds (bounds of UL tile / LR tile)
ul_tile = tms._tile(bounds[0], bounds[3], base_zoom)
w, _, _, n = tms.xy_bounds(ul_tile)
# The output resolution should match the TMS resolution at MaxZoom
vrt_res = tms._resolution(tms.matrix(max_zoom))
# Output transform is built from the origin (UL tile) and output resolution
vrt_transform = Affine(vrt_res, 0, w, 0, -vrt_res, n)
lr_tile = tms._tile(bounds[2], bounds[1], base_zoom)
e, _, _, s = tms.xy_bounds(
morecantile.Tile(lr_tile.x + 1, lr_tile.y + 1, lr_tile.z)
)
vrt_width = max(1, round((e - w) / vrt_transform.a))
vrt_height = max(1, round((s - n) / vrt_transform.e))
return dict(
crs=tms.rasterio_crs,
transform=vrt_transform,
width=vrt_width,
height=vrt_height,
)
def get_zooms(
src_dst: Union[DatasetReader, DatasetWriter, WarpedVRT],
tilesize: int = 256,
tms: morecantile.TileMatrixSet = morecantile.tms.get("WebMercatorQuad"),
zoom_level_strategy: str = "auto",
) -> Tuple[int, int]:
"""Calculate raster min/max zoom level."""
# If the raster is not in the TMS CRS we calculate its projected properties (height, width, resolution)
if src_dst.crs != tms.rasterio_crs:
aff, w, h = calculate_default_transform(
src_dst.crs,
tms.rasterio_crs,
src_dst.width,
src_dst.height,
*src_dst.bounds,
)
else:
aff = list(src_dst.transform)
w = src_dst.width
h = src_dst.height
resolution = max(abs(aff[0]), abs(aff[4]))
# The maxzoom is defined by finding the minimum difference between
# the raster resolution and the zoom level resolution
max_zoom = tms.zoom_for_res(
resolution,
max_z=30,
zoom_level_strategy=zoom_level_strategy,
)
# The minzoom is defined by the resolution of the maximum theoretical overview level
max_possible_overview_level = get_maximum_overview_level(w, h, minsize=tilesize)
ovr_resolution = resolution * (2**max_possible_overview_level)
min_zoom = tms.zoom_for_res(ovr_resolution, max_z=30)
return (min_zoom, max_zoom)
