Skip to content
Permalink
Browse files

Initial version of xyz tiles export (processing tool)

  • Loading branch information
Marcel Dancak
Marcel Dancak committed Apr 24, 2019
1 parent 04409ac commit 73a5a6adc195186525f5f742d0d0032dc0aa37b3
Showing with 366 additions and 0 deletions.
  1. +366 −0 python/plugins/processing/algs/qgis/TilesXYZ.py
@@ -0,0 +1,366 @@
# -*- coding: utf-8 -*-

"""
***************************************************************************
TilesXYZ.py
---------------------
Date : April 2019
Copyright : (C) 2019 by Lutra Consulting Limited
Email : marcel.dancak@lutraconsulting.co.uk
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""

__author__ = 'Marcel Dancak'
__date__ = 'April 2019'
__copyright__ = '(C) 2019 by Lutra Consulting Limited'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'

import os
import math
from uuid import uuid4

import ogr
import gdal
from qgis.PyQt.QtCore import QSize, Qt, QByteArray, QBuffer
from qgis.PyQt.QtGui import QColor, QImage, QPainter
from qgis.core import (QgsProcessingException,
QgsProcessingParameterEnum,
QgsProcessingParameterNumber,
QgsProcessingParameterBoolean,
QgsProcessingParameterString,
QgsProcessingParameterExtent,
QgsProcessingOutputFile,
QgsProcessingParameterFileDestination,
QgsProcessingParameterFolderDestination,
QgsProject,
QgsGeometry,
QgsRectangle,
QgsMapSettings,
QgsCoordinateTransform,
QgsCoordinateReferenceSystem,
QgsMapRendererCustomPainterJob)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm


# Math functions taken from https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
def deg2num(lat_deg, lon_deg, zoom):
lat_rad = math.radians(lat_deg)
n = 2.0 ** zoom
xtile = int((lon_deg + 180.0) / 360.0 * n)
ytile = int((1.0 - math.log(math.tan(lat_rad) + (1 / math.cos(lat_rad))) / math.pi) / 2.0 * n)
return (xtile, ytile)

def num2deg(xtile, ytile, zoom):
n = 2.0 ** 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)


class Tile:
def __init__(self, x, y, z):
self.x = x
self.y = y
self.z = z

def extent(self):
lat1, lon1 = num2deg(self.x, self.y, self.z)
lat2, lon2 = num2deg(self.x + 1, self.y + 1, self.z)
return [lon1, lat2, lon2, lat1]


class MetaTile:
def __init__(self):
# list of tuple(row index, column index, Tile)
self.tiles = []

def add_tile(self, row, column, tile):
self.tiles.append((row, column, tile))

def rows(self):
return max([r for r, _, _ in self.tiles]) + 1

def columns(self):
return max([c for _, c, _ in self.tiles]) + 1

def extent(self):
_, _, first = self.tiles[0]
_, _, last = self.tiles[-1]
lat1, lon1 = num2deg(first.x, first.y, first.z)
lat2, lon2 = num2deg(last.x + 1, last.y + 1, first.z)
return [lon1, lat2, lon2, lat1]


def get_metatiles(extent, zoom, size=4):
west_edge, south_edge, east_edge, north_edge = extent
left_tile, top_tile = deg2num(north_edge, west_edge, zoom)
right_tile, bottom_tile = deg2num(south_edge, east_edge, zoom)

metatiles = {}
for i, x in enumerate(range(left_tile, right_tile + 1)):
for j, y in enumerate(range(top_tile, bottom_tile + 1)):
meta_key = '{}:{}'.format(int(i / size), int(j / size))
if meta_key not in metatiles:
metatiles[meta_key] = MetaTile()
metatile = metatiles[meta_key]
metatile.add_tile(i % size, j % size, Tile(x, y, zoom))

return list(metatiles.values())


class DirectoryWriter:
def __init__(self, folder, tile_params):
self.folder = folder
self.format = tile_params.get('format', 'PNG')
self.quality = tile_params.get('quality', -1)

def writeTile(self, tile, image):
directory = os.path.join(self.folder, str(tile.z), str(tile.x))
os.makedirs(directory, exist_ok=True)
path = os.path.join(directory, '{}.{}'.format(tile.y, self.format.lower()))
image.save(path, self.format, self.quality)
return path

def close(self):
return self.folder


class MBTilesWriter:
def __init__(self, filename, tile_params, extent, min_zoom, max_zoom):
base_dir = os.path.dirname(filename)
os.makedirs(base_dir, exist_ok=True)
self.filename = filename
self.extent = extent
self.tile_width = tile_params.get('width', 256)
self.tile_height = tile_params.get('height', 256)
tile_format = tile_params['format']
if tile_format == 'JPG':
tile_format = 'JPEG'
options = ['QUALITY=%s' % tile_params.get('quality', 75)]
else:
options = ['ZLEVEL=8']
driver = gdal.GetDriverByName('MBTiles')
ds = driver.Create(filename, 1, 1, 1, options=['TILE_FORMAT=%s' % tile_format] + options)
ds = None
sqlite_driver = ogr.GetDriverByName('SQLite')
ds = sqlite_driver.Open(filename, 1)
ds.ExecuteSQL("INSERT INTO metadata(name, value) VALUES ('{}', '{}');".format('minzoom', min_zoom))
ds.ExecuteSQL("INSERT INTO metadata(name, value) VALUES ('{}', '{}');".format('maxzoom', max_zoom))
# will be set properly after writing all tiles
ds.ExecuteSQL("INSERT INTO metadata(name, value) VALUES ('{}', '');".format('bounds'))
ds = None
self._zoom = None

def _initZoomLayer(self, first_tile):
first_tile_extent = first_tile.extent()
sqlite_driver = ogr.GetDriverByName('SQLite')
ds = sqlite_driver.Open(self.filename, 1)
zoom_extent = [
first_tile_extent[0],
# extend with height of 1 tile, but do not exceed -89.98 to stay in valid range (gdal)
max(-89.98, self.extent[1] - (first_tile_extent[3] - first_tile_extent[1])),
# extend with width of 1 tile, do not exceed 180
min(180, self.extent[2] + (first_tile_extent[2] - first_tile_extent[0])),
first_tile_extent[3]
]
bounds = ','.join(map(str, zoom_extent))
ds.ExecuteSQL("UPDATE metadata SET value='{}' WHERE name='bounds'".format(bounds))
ds = None

self._zoomDs = gdal.OpenEx(self.filename, 1, open_options=['ZOOM_LEVEL=%s' % first_tile.z])
self._first_tile = first_tile
self._zoom = first_tile.z

def writeTile(self, tile, image):
if tile.z != self._zoom:
self._initZoomLayer(tile)

data = QByteArray()
buff = QBuffer(data)
image.save(buff, 'PNG')

mmap_name = '/vsimem/' + uuid4().hex
gdal.FileFromMemBuffer(mmap_name, data.data())
gdal_dataset = gdal.Open(mmap_name)
data = gdal_dataset.ReadRaster(0, 0, self.tile_width, self.tile_height)
gdal_dataset = None
gdal.Unlink(mmap_name)

xoff = (tile.x - self._first_tile.x) * self.tile_width
yoff = (tile.y - self._first_tile.y) * self.tile_height
self._zoomDs.WriteRaster(xoff, yoff, self.tile_width, self.tile_height, data)

def close(self):
self._zoomDs = None
sqlite_driver = ogr.GetDriverByName('SQLite')
ds = sqlite_driver.Open(self.filename, 1)
bounds = ','.join(map(str, self.extent))
ds.ExecuteSQL("UPDATE metadata SET value='{}' WHERE name='bounds'".format(bounds))
ds = None
return self.filename


class TilesXYZ(QgisAlgorithm):
NAME = 'NAME'
EXTENT = 'EXTENT'
ZOOM_MIN = 'ZOOM_MIN'
ZOOM_MAX = 'ZOOM_MAX'
TILE_FORMAT = 'TILE_FORMAT'
DPI = 'DPI'
OUTPUT_FORMAT = 'OUTPUT_FORMAT'
OUTPUT_DIRECTORY = 'OUTPUT_DIRECTORY'

def group(self):
return self.tr('Raster tools')

def groupId(self):
return 'rastertools'

def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterString(self.NAME, self.tr('Name'), defaultValue='Test'))
self.addParameter(QgsProcessingParameterFolderDestination(self.OUTPUT_DIRECTORY, self.tr('Output directory')))

self.addParameter(QgsProcessingParameterExtent(self.EXTENT, self.tr('Extent')))
self.addParameter(QgsProcessingParameterNumber(self.ZOOM_MIN,
self.tr('Minimum zoom'),
defaultValue=12))
self.addParameter(QgsProcessingParameterNumber(self.ZOOM_MAX,
self.tr('Maximum zoom'),
defaultValue=12))
self.addParameter(QgsProcessingParameterNumber(self.DPI, self.tr('DPI'), defaultValue=96))

self.formats = ['PNG', 'JPG']
self.addParameter(QgsProcessingParameterEnum(self.TILE_FORMAT,
self.tr('Tile format'),
self.formats,
defaultValue=0))
self.outputs = ['Directory', 'MBTiles']
self.addParameter(QgsProcessingParameterEnum(self.OUTPUT_FORMAT,
self.tr('Output format'),
self.outputs,
defaultValue=0))


def name(self):
return 'tilesxyz'

def displayName(self):
return self.tr('Generate XYZ tiles')

def processAlgorithm(self, parameters, context, feedback):
feedback.setProgress(1)

name = self.parameterAsString(parameters, self.NAME, context)
output_dir = self.parameterAsString(parameters, self.OUTPUT_DIRECTORY, context)
extent = self.parameterAsExtent(parameters, self.EXTENT, context)
min_zoom = self.parameterAsInt(parameters, self.ZOOM_MIN, context)
max_zoom = self.parameterAsInt(parameters, self.ZOOM_MAX, context)
dpi = self.parameterAsInt(parameters, self.DPI, context)
tile_format = self.formats[self.parameterAsEnum(parameters, self.TILE_FORMAT, context)]
output_format = self.outputs[self.parameterAsEnum(parameters, self.OUTPUT_FORMAT, context)]
tile_width = 256
tile_height = 256

project = QgsProject.instance()
visible_layers = [item.layer() for item in project.layerTreeRoot().findLayers() if item.isVisible()]
layers = [l for l in project.layerTreeRoot().layerOrder() if l in visible_layers]

wgs_crs = QgsCoordinateReferenceSystem('EPSG:4326')
dest_crs = QgsCoordinateReferenceSystem('EPSG:3857')

src_to_wgs = QgsCoordinateTransform(project.crs(), wgs_crs, context.transformContext())
wgs_to_dest = QgsCoordinateTransform(wgs_crs, dest_crs, context.transformContext())

settings = QgsMapSettings()
settings.setOutputImageFormat(QImage.Format_ARGB32_Premultiplied)
settings.setDestinationCrs(dest_crs)
settings.setLayers(layers)
settings.setOutputDpi(dpi)

wgs_extent = src_to_wgs.transform(extent)
wgs_extent = [wgs_extent.xMinimum(), wgs_extent.yMinimum(), wgs_extent.xMaximum(), wgs_extent.yMaximum()]

metatiles_by_zoom = {}
metatiles_count = 0
for zoom in range(min_zoom, max_zoom + 1):
metatiles = get_metatiles(wgs_extent, zoom, 4)
metatiles_by_zoom[zoom] = metatiles
metatiles_count += len(metatiles)

lab_buffer_px = 100
progress = 0

tile_params = {
'format': tile_format,
'quality': 75,
'width': tile_width,
'height': tile_height
}
if output_format == 'Directory':
writer = DirectoryWriter(os.path.join(output_dir, name), tile_params)
else:
filename = os.path.join(output_dir, '%s.mbtiles' % name)
writer = MBTilesWriter(filename, tile_params, wgs_extent, min_zoom, max_zoom)

for zoom in range(min_zoom, max_zoom + 1):
feedback.pushConsoleInfo('Generating tiles for zoom level: %s' % zoom)

for i, metatile in enumerate(metatiles_by_zoom[zoom]):
size = QSize(tile_width * metatile.rows(), tile_height * metatile.columns())
extent = QgsRectangle(*metatile.extent())
# TODO: transformation of bounding points?
settings.setExtent(wgs_to_dest.transform(extent))
settings.setOutputSize(size)

label_area = QgsRectangle(settings.extent())
lab_buffer = label_area.width() * (lab_buffer_px / size.width())
label_area.set(
label_area.xMinimum() + lab_buffer,
label_area.yMinimum() + lab_buffer,
label_area.xMaximum() - lab_buffer,
label_area.yMaximum() - lab_buffer
)
settings.setLabelBoundaryGeometry(QgsGeometry.fromRect(label_area))

image = QImage(size, QImage.Format_ARGB32_Premultiplied)
image.fill(Qt.transparent)
dpm = settings.outputDpi() / 25.4 * 1000
image.setDotsPerMeterX(dpm)
image.setDotsPerMeterY(dpm)
painter = QPainter(image)
job = QgsMapRendererCustomPainterJob(settings, painter)
job.renderSynchronously()
painter.end()

# For analysing metatiles (labels, etc.)
metatile_dir = os.path.join(output_dir, name, str(zoom))
os.makedirs(metatile_dir, exist_ok=True)
image.save(os.path.join(metatile_dir, 'metatile_%s.png' % i))

progress += 1
feedback.setProgress(100 * (progress / metatiles_count))
for r, c, tile in metatile.tiles:
tile_img = image.copy(tile_width * r, tile_height * c, tile_width, tile_height)
writer.writeTile(tile, tile_img)

output = writer.close()
return {'OUTPUT': output}

def checkParameterValues(self, parameters, context):
min_zoom = self.parameterAsInt(parameters, self.ZOOM_MIN, context)
max_zoom = self.parameterAsInt(parameters, self.ZOOM_MAX, context)
if max_zoom < min_zoom:
return False, self.tr('Invalid zoom levels range.')

return super().checkParameterValues(parameters, context)

0 comments on commit 73a5a6a

Please sign in to comment.
You can’t perform that action at this time.