"""Tiling functions for fast visualization of the SFINCS model in- and output data."""
import math
import os
from itertools import product
from pathlib import Path
from typing import List, Union
import geopandas as gpd
import numpy as np
import xarray as xr
from affine import Affine
from PIL import Image
from pyproj import Transformer
from .merge import merge_multi_dataarrays
__all__ = ["create_topobathy_tiles", "downscale_floodmap_webmercator"]
[docs]def downscale_floodmap_webmercator(
zsmax: Union[np.array, xr.DataArray],
index_path: str,
topobathy_path: str,
floodmap_path: str,
hmin: float = 0.05,
zoom_range: Union[int, List[int]] = [0, 13],
fmt_in: str = "bin",
fmt_out: str = "png",
merge: bool = True, # FIXME: this is not implemented yet
):
"""Create a downscaled floodmap for (model) region in webmercator tile format
Parameters
----------
zsmax : Union[np.array, xr.DataArray]
DataArray with maximum water level (m) for each cell
index_path : str
Directory with index files
topobathy_path : str
Directory with topobathy files
floodmap_path : str
Directory where floodmap files will be stored
hmin : float, optional
Minimum water depth considered as "flooded", by default 0.05 m
zoom_range : Union[int, List[int]], optional
Range of zoom levels, by default [0, 13]
fmt_in : str, optional
Format of the index and topobathy tiles, by default "bin"
fmt_out : str, optional
Format of the floodmap tiles to be created, by default "png"
merge : bool, optional
Merge floodmap tiles with existing floodmap tiles
(this could for example happen when there is overlap between models),
by default True
"""
# if zsmax is an xarray, convert to numpy array
if isinstance(zsmax, xr.DataArray):
zsmax = zsmax.values
zsmax = zsmax.flatten()
# if only one zoom level is specified, create tiles up to that zoom level (inclusive)
if isinstance(zoom_range, int):
zoom_range = [0, zoom_range]
for izoom in range(zoom_range[0], zoom_range[1] + 1):
index_zoom_path = os.path.join(index_path, str(izoom))
if not os.path.exists(index_zoom_path):
continue
# list the available x-folders
x_folders = [f.path for f in os.scandir(index_zoom_path) if f.is_dir()]
# loop over x-folders
for x_folder in x_folders:
x = os.path.basename(x_folder)
# list the available y-files with fmt_in extension
y_files = []
# Iterate directory
for file in os.listdir(x_folder):
# check only text files
if file.endswith(fmt_in):
y_files.append(file)
# loop over y-files
for y_file in y_files:
# read the index file
index_fn = os.path.join(x_folder, y_file)
if fmt_in == "bin":
ind = np.fromfile(index_fn, dtype="i4")
elif fmt_in == "png":
ind = png2int(index_fn)
# read the topobathy file
dep_fn = os.path.join(topobathy_path, str(izoom), x, y_file)
if fmt_in == "bin":
dep = np.fromfile(dep_fn, dtype="f4")
elif fmt_in == "png":
dep = png2elevation(dep_fn)
# create the floodmap
hmax = zsmax[ind]
hmax = hmax - dep
hmax[hmax < hmin] = np.nan
hmax = hmax.reshape(256, 256)
# save the floodmap
if np.isnan(hmax).all():
# only nans in this tile
continue
if not os.path.exists(os.path.join(floodmap_path, str(izoom), x)):
os.makedirs(os.path.join(floodmap_path, str(izoom), x))
floodmap_fn = os.path.join(
floodmap_path, str(izoom), x, y_file.replace(fmt_in, fmt_out)
)
if fmt_out == "bin":
# And write indices to file
fid = open(floodmap_fn, "wb")
fid.write(hmax)
fid.close()
elif fmt_out == "png":
elevation2png(hmax, floodmap_fn)
[docs]def create_topobathy_tiles(
root: Union[str, Path],
region: gpd.GeoDataFrame,
datasets_dep: List[dict],
index_path: Union[str, Path] = None,
zoom_range: Union[int, List[int]] = [0, 13],
z_range: List[int] = [-20000.0, 20000.0],
fmt="bin",
):
"""Create webmercator topobathy tiles for a given region.
Parameters
----------
root : Union[str, Path]
Directory where the topobathy tiles will be stored.
region : gpd.GeoDataFrame
GeoDataFrame defining the region for which the tiles will be created.
datasets_dep : List[dict]
List of dictionaries containing the bathymetry dataarrays.
index_path : Union[str, Path], optional
Directory where index tiles are stored, by default None
zoom_range : Union[int, List[int]], optional
Range of zoom levels for which tiles are created, by default [0, 13]
z_range : List[int], optional
Range of valid elevations, by default [-20000.0, 20000.0]
format : str, optional
The desired output format of the topobathy tiles, by default "bin". Also "png" and "tif" are supported.
"""
# TODO change the order of the zoom_levels
# basing large scale zoom levels on the high-resolution ones prevents memory errors
assert len(datasets_dep) > 0, "No DEMs provided"
topobathy_path = os.path.join(root, "topobathy")
npix = 256
# for binary format, use .dat extension
if fmt == "bin":
extension = "dat"
# for net, tif and png extension and format are the same
else:
extension = fmt
# if only one zoom level is specified, create tiles up to that zoom level (inclusive)
if isinstance(zoom_range, int):
zoom_range = [0, zoom_range]
# get bounding box of region
minx, miny, maxx, maxy = region.total_bounds
transformer = Transformer.from_crs(region.crs.to_epsg(), 3857)
# axis order is different for geographic and projected CRS
if region.crs.is_geographic:
minx, miny = map(
max, zip(transformer.transform(miny, minx), [-20037508.34] * 2)
)
maxx, maxy = map(min, zip(transformer.transform(maxy, maxx), [20037508.34] * 2))
else:
minx, miny = map(
max, zip(transformer.transform(minx, miny), [-20037508.34] * 2)
)
maxx, maxy = map(min, zip(transformer.transform(maxx, maxy), [20037508.34] * 2))
for izoom in range(zoom_range[0], zoom_range[1] + 1):
print("Processing zoom level " + str(izoom))
zoom_path = os.path.join(topobathy_path, str(izoom))
for transform, col, row in tile_window(izoom, minx, miny, maxx, maxy):
# transform is a rasterio Affine object
# col, row are the tile indices
file_name = os.path.join(zoom_path, str(col), str(row) + "." + extension)
if index_path:
# Only make tiles for which there is an index file (can be .dat or .png)
index_file_name_dat = os.path.join(
index_path, str(izoom), str(col), str(row) + ".dat"
)
index_file_name_png = os.path.join(
index_path, str(izoom), str(col), str(row) + ".png"
)
if not os.path.exists(index_file_name_dat) and not os.path.exists(
index_file_name_png
):
continue
x = np.arange(0, npix) + 0.5
y = np.arange(0, npix) + 0.5
x3857, y3857 = transform * (x, y)
zg = np.float32(np.full([npix, npix], np.nan))
da_dep = xr.DataArray(
zg,
coords={"y": y3857, "x": x3857},
dims=["y", "x"],
)
da_dep.raster.set_crs(3857)
# get subgrid bathymetry tile
da_dep = merge_multi_dataarrays(
da_list=datasets_dep,
da_like=da_dep,
)
if np.isnan(da_dep.values).all():
# only nans in this tile
continue
if (
np.nanmax(da_dep.values) < z_range[0]
or np.nanmin(da_dep.values) > z_range[1]
):
# all values in tile outside z_range
continue
if not os.path.exists(os.path.join(zoom_path, str(col))):
os.makedirs(os.path.join(zoom_path, str(col)))
if fmt == "bin":
# And write indices to file
fid = open(file_name, "wb")
fid.write(da_dep.values)
fid.close()
elif fmt == "png":
elevation2png(da_dep, file_name)
elif fmt == "tif":
da_dep.raster.to_raster(file_name)
def deg2num(lat_deg, lon_deg, zoom):
"""Convert lat/lon to webmercator tile number"""
lat_rad = math.radians(lat_deg)
n = 2**zoom
xtile = int((lon_deg + 180.0) / 360.0 * n)
ytile = int((1.0 - math.asinh(math.tan(-lat_rad)) / math.pi) / 2.0 * n)
return (xtile, ytile)
def num2deg(xtile, ytile, zoom):
"""Convert webmercator tile number to lat/lon"""
n = 2**zoom
lon_deg = xtile / n * 360.0 - 180.0
lat_rad = math.atan(math.sinh(math.pi * (1 - 2 * ytile / n)))
lat_deg = math.degrees(-lat_rad)
return (lat_deg, lon_deg)
def rgba2int(rgba):
"""Convert rgba tuple to int"""
r, g, b, a = rgba
return (r * 256**3) + (g * 256**2) + (b * 256) + a
def int2rgba(int_val):
"""Convert int to rgba tuple"""
r = (int_val // 256**3) % 256
g = (int_val // 256**2) % 256
b = (int_val // 256) % 256
a = int_val % 256
return (r, g, b, a)
def elevation2rgb(val):
"""Convert elevation to rgb tuple"""
val += 32768
r = np.floor(val / 256)
g = np.floor(val % 256)
b = np.floor((val - np.floor(val)) * 256)
return (r, g, b)
def rgb2elevation(r, g, b):
"""Convert rgb tuple to elevation"""
val = (r * 256 + g + b / 256) - 32768
return val
def png2int(png_file):
"""Convert png to int array"""
# Open the PNG image
image = Image.open(png_file)
# Convert the image to RGBA mode if it's not already in RGBN mode
if image.mode != "RGBA":
image = image.convert("RGBA")
# Get the pixel data from the image
pixel_data = list(image.getdata())
# Convert RGBA values to unique integers
val = []
for rgba in pixel_data:
val.append(rgba2int(rgba))
return val
def int2png(val, png_file):
"""Convert int array to png"""
# Convert index integers to RGBA values
rgba = np.zeros((256 * 256, 4), "uint8")
r, g, b, a = int2rgba(val)
rgba[:, 0] = r.flatten()
rgba[:, 1] = g.flatten()
rgba[:, 2] = b.flatten()
rgba[:, 3] = a.flatten()
rgba = rgba.reshape([256, 256, 4])
# Create PIL Image from RGB values and save as PNG
img = Image.fromarray(rgba)
img.save(png_file)
def png2elevation(png_file):
"""Convert png to elevation array based on terrarium interpretation"""
img = Image.open(png_file)
arr = np.array(img.convert("RGB"))
# Convert RGB values to elevation values
elevations = np.apply_along_axis(rgb2elevation, 2, arr)
return elevations
def elevation2png(val, png_file):
"""Convert elevation array to png using terrarium interpretation"""
rgb = np.zeros((256 * 256, 3), "uint8")
r, g, b = elevation2rgb(val)
rgb[:, 0] = r.values.flatten()
rgb[:, 1] = g.values.flatten()
rgb[:, 2] = b.values.flatten()
rgb = rgb.reshape([256, 256, 3])
# Create PIL Image from RGB values and save as PNG
img = Image.fromarray(rgb)
img.save(png_file)
def tile_window(zl, minx, miny, maxx, maxy):
"""Window generator for a given zoom level and bounding box"""
dxy = (20037508.34 * 2) / (2**zl)
# Origin displacement
odx = np.floor(abs(-20037508.34 - minx) / dxy)
ody = np.floor(abs(20037508.34 - maxy) / dxy)
# Set the new origin
minx = -20037508.34 + odx * dxy
maxy = 20037508.34 - ody * dxy
# Create window generator
lu = product(np.arange(minx, maxx, dxy), np.arange(maxy, miny, -dxy))
for l, u in lu:
col = int(odx + (l - minx) / dxy)
row = int(ody + (maxy - u) / dxy)
yield Affine(dxy / 256, 0, l, 0, -dxy / 256, u), col, row
