def get_datasource(self, logger):
bbox = self._mercator_bbox
dst_bbox = bbox.bounds
dst_x_size = self.size
dst_y_size = self.size
dst_srs = osr.SpatialReference()
dst_srs.ImportFromEPSG(3857)
dst_drv = gdal.GetDriverByName("MEM")
dst_ds = dst_drv.Create('', dst_x_size, dst_y_size, 1, gdal.GDT_Float32)
dst_x_res = float(dst_bbox[2] - dst_bbox[0]) / dst_x_size
dst_y_res = float(dst_bbox[3] - dst_bbox[1]) / dst_y_size
dst_gt = (dst_bbox[0], dst_x_res, 0,
dst_bbox[3], 0, -dst_y_res)
dst_ds.SetGeoTransform(dst_gt)
dst_ds.SetProjection(dst_srs.ExportToWkt())
dst_ds.GetRasterBand(1).SetNoDataValue(FLT_NODATA)
# figure out what the approximate scale of the output image is in
# lat/lon coordinates. this is used to select the appropriate filter.
ll_bbox = self.latlon_bbox()
ll_x_res = float(ll_bbox.bounds[2] - ll_bbox.bounds[0]) / dst_x_size
ll_y_res = float(ll_bbox.bounds[3] - ll_bbox.bounds[1]) / dst_y_size
composite.compose(self, dst_ds, logger, min(ll_x_res, ll_y_res))
try:
yield dst_ds
finally:
del dst_ds
def render(self, tmp_dir):
logger = logging.getLogger('skadi')
bbox = _bbox(self.x, self.y)
mid_dir = os.path.join(tmp_dir, self.output_dir,
("N" if self.y >= 90 else "S") +
("%02d" % abs(self.y - 90)))
if not os.path.isdir(mid_dir):
try:
os.makedirs(mid_dir)
except OSError as e:
# swallow the error if the directory exists - it's
# probably another thread creating it.
if e.errno != errno.EEXIST or not os.path.isdir(mid_dir):
raise
tile = _tile_name(self.x, self.y)
hgt_file = os.path.join(mid_dir, tile + ".hgt")
tile_file = os.path.join(mid_dir, tile + ".hgt.gz")
logger.info("Generating tile %r..." % tile)
dst_bbox = bbox.bounds
dst_x_size = 3601
dst_y_size = 3601
dst_srs = osr.SpatialReference()
dst_srs.ImportFromEPSG(4326)
# for SRTM, must first buffer in memory, then write to disk with
# CreateCopy.
dst_drv = gdal.GetDriverByName("MEM")
dst_ds = dst_drv.Create('', dst_x_size, dst_y_size, 1, gdal.GDT_Int16)
dst_x_res = float(dst_bbox[2] - dst_bbox[0]) / dst_x_size
dst_y_res = float(dst_bbox[3] - dst_bbox[1]) / dst_y_size
dst_gt = (dst_bbox[0], dst_x_res, 0,
dst_bbox[3], 0, -dst_y_res)
dst_ds.SetGeoTransform(dst_gt)
dst_ds.SetProjection(dst_srs.ExportToWkt())
dst_ds.GetRasterBand(1).SetNoDataValue(-32768)
composite.compose(self, dst_ds, logger, min(dst_x_res, dst_y_res))
logger.debug("Writing SRTMHGT: %r" % hgt_file)
srtm_drv = gdal.GetDriverByName("SRTMHGT")
srtm_ds = srtm_drv.CreateCopy(hgt_file, dst_ds)
del dst_ds
del srtm_ds
logger.debug("Compressing HGT -> GZ: %r" % tile_file)
with gzip.open(tile_file, 'wb') as gz, open(hgt_file, 'rb') as hgt:
shutil.copyfileobj(hgt, gz)
os.remove(hgt_file)
assert os.path.isfile(tile_file)
logger.info("Done generating tile %r" % tile)
def render(self, tmp_dir):
logger = logging.getLogger('skadi')
bbox = _bbox(self.x, self.y)
mid_dir = os.path.join(tmp_dir, self.output_dir,
("N" if self.y >= 90 else "S") +
("%02d" % abs(self.y - 90)))
if not os.path.isdir(mid_dir):
try:
os.makedirs(mid_dir)
except OSError as e:
# swallow the error if the directory exists - it's
# probably another thread creating it.
if e.errno != errno.EEXIST or not os.path.isdir(mid_dir):
raise
tile = _tile_name(self.x, self.y)
hgt_file = os.path.join(mid_dir, tile + ".hgt")
tile_file = os.path.join(mid_dir, tile + ".hgt.gz")
logger.info("Generating tile %r..." % tile)
dst_bbox = bbox.bounds
dst_x_size = 3601
dst_y_size = 3601
dst_srs = osr.SpatialReference()
dst_srs.ImportFromEPSG(4326)
# for SRTM, must first buffer in memory, then write to disk with
# CreateCopy.
dst_drv = gdal.GetDriverByName("MEM")
dst_ds = dst_drv.Create('', dst_x_size, dst_y_size, 1, gdal.GDT_Int16)
dst_x_res = float(dst_bbox[2] - dst_bbox[0]) / dst_x_size
dst_y_res = float(dst_bbox[3] - dst_bbox[1]) / dst_y_size
dst_gt = (dst_bbox[0], dst_x_res, 0, dst_bbox[3], 0, -dst_y_res)
dst_ds.SetGeoTransform(dst_gt)
dst_ds.SetProjection(dst_srs.ExportToWkt())
dst_ds.GetRasterBand(1).SetNoDataValue(-32768)
composite.compose(self, dst_ds, logger, min(dst_x_res, dst_y_res))
logger.debug("Writing SRTMHGT: %r" % hgt_file)
srtm_drv = gdal.GetDriverByName("SRTMHGT")
srtm_ds = srtm_drv.CreateCopy(hgt_file, dst_ds)
del dst_ds
del srtm_ds
logger.debug("Compressing HGT -> GZ: %r" % tile_file)
with gzip.open(tile_file, 'wb') as gz, open(hgt_file, 'rb') as hgt:
shutil.copyfileobj(hgt, gz)
os.remove(hgt_file)
assert os.path.isfile(tile_file)
logger.info("Done generating tile %r" % tile)
def render(self, tmp_dir):
logger = logging.getLogger('normal')
bbox = self._mercator_bbox
mid_dir = os.path.join(tmp_dir, self.output_dir,
str(self.z), str(self.x))
mkdir_p(mid_dir)
tile = self.tile_name()
tile_file = os.path.join(tmp_dir, self.output_dir,
tile + ".png")
logger.debug("Generating tile %r..." % tile)
filter_size = 10
outfile = tile_file
dst_bbox = bbox.bounds
dst_x_size = 256
dst_y_size = 256
dst_x_res = float(dst_bbox[2] - dst_bbox[0]) / dst_x_size
dst_y_res = float(dst_bbox[3] - dst_bbox[1]) / dst_y_size
dst_srs = osr.SpatialReference()
dst_srs.ImportFromEPSG(3857)
# expand bbox & image to generate "bleed" for image filter
mid_min_x = dst_bbox[0] - filter_size * dst_x_res
mid_min_y = dst_bbox[1] - filter_size * dst_y_res
mid_max_x = dst_bbox[2] + filter_size * dst_x_res
mid_max_y = dst_bbox[3] + filter_size * dst_y_res
filter_top_margin = filter_size
filter_bot_margin = filter_size
filter_lft_margin = filter_size
filter_rgt_margin = filter_size
# clip bounding box back to the edges of the world. GDAL can handle
# wrapping around the world, but it doesn't give the results that
# would be expected.
if mid_min_x < -0.5 * mercator.MERCATOR_WORLD_SIZE:
filter_lft_margin = 0
mid_min_x = dst_bbox[0]
if mid_min_y < -0.5 * mercator.MERCATOR_WORLD_SIZE:
filter_bot_margin = 0
mid_min_y = dst_bbox[1]
if mid_max_x > 0.5 * mercator.MERCATOR_WORLD_SIZE:
filter_rgt_margin = 0
mid_max_x = dst_bbox[2]
if mid_max_y > 0.5 * mercator.MERCATOR_WORLD_SIZE:
filter_top_margin = 0
mid_max_y = dst_bbox[3]
mid_x_size = dst_x_size + filter_lft_margin + filter_rgt_margin
mid_y_size = dst_y_size + filter_bot_margin + filter_top_margin
mid_bbox = (mid_min_x, mid_min_y, mid_max_x, mid_max_y)
mid_drv = gdal.GetDriverByName("MEM")
mid_ds = mid_drv.Create('', mid_x_size, mid_y_size, 1, gdal.GDT_Float32)
mid_gt = (mid_bbox[0], dst_x_res, 0,
mid_bbox[3], 0, -dst_y_res)
mid_ds.SetGeoTransform(mid_gt)
mid_ds.SetProjection(dst_srs.ExportToWkt())
mid_ds.GetRasterBand(1).SetNoDataValue(mercator.FLT_NODATA)
# figure out what the approximate scale of the output image is in
# lat/lon coordinates. this is used to select the appropriate filter.
ll_bbox = self._latlon_bbox
ll_x_res = float(ll_bbox.bounds[2] - ll_bbox.bounds[0]) / dst_x_size
ll_y_res = float(ll_bbox.bounds[3] - ll_bbox.bounds[1]) / dst_y_size
# calculate the resolution of a pixel in real meters for both x and y.
# this will be used to scale the gradient so that it's consistent
# across zoom levels.
ll_mid_x = 0.5 * (ll_bbox.bounds[2] + ll_bbox.bounds[0])
ll_spc_x = 0.5 * (ll_bbox.bounds[2] - ll_bbox.bounds[0]) / dst_x_size
ll_mid_y = 0.5 * (ll_bbox.bounds[3] + ll_bbox.bounds[1])
ll_spc_y = 0.5 * (ll_bbox.bounds[3] - ll_bbox.bounds[1]) / dst_y_size
geod = Geodesic.WGS84
# NOTE: in defiance of predictability and regularity, the geod methods
# take input as (lat, lon) in that order, rather than (x, y) as would
# be sensible.
# NOTE: at low zooms, taking the width across the tile starts to break
# down, so we take the width across a small portion of the interior of
# the tile instead.
geodesic_res_x = -1.0 / \
geod.Inverse(ll_mid_y, ll_mid_x - ll_spc_x,
ll_mid_y, ll_mid_x + ll_spc_x)['s12']
geodesic_res_y = 1.0 / \
geod.Inverse(ll_mid_y - ll_spc_y, ll_mid_x,
ll_mid_y + ll_spc_y, ll_mid_x)['s12']
composite.compose(self, mid_ds, logger, min(ll_x_res, ll_y_res))
pixels = mid_ds.GetRasterBand(1).ReadAsArray(0, 0, mid_x_size, mid_y_size)
ygrad, xgrad = numpy.gradient(pixels, 2)
img = numpy.dstack((geodesic_res_x * xgrad, geodesic_res_y * ygrad,
numpy.ones((mid_y_size, mid_x_size))))
# first, we normalise to unit vectors. this puts each element of img
# in the range (-1, 1). the "einsum" stuff is serious black magic, but
# what it (should be) saying is "for each i,j in the rows and columns,
# the output is the sum of img[i,j,k]*img[i,j,k]" - i.e: the square.
norm = numpy.sqrt(numpy.einsum('ijk,ijk->ij', img, img))
# the norm is now the "wrong shape" according to numpy, so we need to
# copy the norm value out into RGB components.
norm_copy = norm[:, :, numpy.newaxis]
# dividing the img by norm_copy should give us RGB components with
# values between -1 and 1, but we need values between 0 and 255 for
# PNG channels. so we move and scale the values to fit in that range.
scaled = (128.0 * (img / norm_copy + 1.0))
# and finally clip it to (0, 255) just in case
img = numpy.clip(scaled, 0.0, 255.0)
# Create output as a 4-channel RGBA image, each (byte) channel
# corresponds to x, y, z, h where x, y and z are the respective
# components of the normal, and h is an index into a hypsometric tint
# table (see HEIGHT_TABLE).
dst_ds = mid_drv.Create('', dst_x_size, dst_y_size, 4, gdal.GDT_Byte)
dst_gt = (dst_bbox[0], dst_x_res, 0,
dst_bbox[3], 0, -dst_y_res)
dst_ds.SetGeoTransform(dst_gt)
dst_ds.SetProjection(dst_srs.ExportToWkt())
# apply the height mapping function to get the table index.
func = numpy.vectorize(_height_mapping_func)
hyps = func(pixels).astype(numpy.uint8)
# extract the area without the "bleed" margin.
ext = img[filter_top_margin:(filter_top_margin+dst_y_size), \
filter_lft_margin:(filter_lft_margin+dst_x_size)]
dst_ds.GetRasterBand(1).WriteArray(ext[...,0].astype(numpy.uint8))
dst_ds.GetRasterBand(2).WriteArray(ext[...,1].astype(numpy.uint8))
dst_ds.GetRasterBand(3).WriteArray(ext[...,2].astype(numpy.uint8))
# add hypsometric tint index as alpha channel
dst_ds.GetRasterBand(4).WriteArray(
hyps[filter_top_margin:(filter_top_margin+dst_y_size),
filter_lft_margin:(filter_lft_margin+dst_x_size)])
png_drv = gdal.GetDriverByName("PNG")
png_ds = png_drv.CreateCopy(tile_file, dst_ds)
# explicitly delete the datasources. the Python-GDAL docs suggest that
# this is a good idea not only to dispose of memory buffers but also
# to ensure that the backing file handles are closed.
del png_ds
del dst_ds
del mid_ds
assert os.path.isfile(tile_file)
source_names = [type(s).__name__ for s in self.sources]
logger.info("Done generating tile %r from %s"
% (tile, ", ".join(source_names)))
