def __call__(self, src_ds, footprint_wkt):
logger.info("Applying AlphaBandOptimization")
dt = src_ds.GetRasterBand(1).DataType
if src_ds.RasterCount == 3:
src_ds.AddBand(dt)
elif src_ds.RasterCount == 4:
pass # okay
else:
raise Exception("Cannot add alpha band, as the current number of "
"bands '%d' does not match" % src_ds.RasterCount)
# initialize the alpha band with zeroes (completely transparent)
band = src_ds.GetRasterBand(4)
band.Fill(0)
# set up the layer with geometry
ogr_ds = ogr.GetDriverByName('Memory').CreateDataSource('wkt')
sr = osr.SpatialReference()
sr.ImportFromEPSG(4326)
layer = ogr_ds.CreateLayer('poly', srs=sr.sr)
feat = ogr.Feature(layer.GetLayerDefn())
feat.SetGeometryDirectly(ogr.Geometry(wkt=footprint_wkt))
layer.CreateFeature(feat)
# rasterize the polygon, burning the opaque value into the alpha band
gdal.RasterizeLayer(src_ds, [4],
layer,
burn_values=[get_limits(dt)[1]])
def __init__(self, dataset, wkt, srid=None, temporary_directory=None):
super(GDALGeometryMaskMergeSource, self).__init__(dataset)
srs = None
srid = 4326
if srid is not None:
srs = osr.SpatialReference()
srs.ImportFromEPSG(srid)
# create a geometry from the given WKT
#geom = ogr.CreateGeometryFromWkt(wkt)
# create an in-memory datasource and add one single layer
ogr_mem_driver = ogr.GetDriverByName("Memory")
data_source = ogr_mem_driver.CreateDataSource("xxx")
layer = data_source.CreateLayer("poly", srs)
# create a single feature and add the given geometry
feature = ogr.Feature(layer.GetLayerDefn())
feature.SetGeometryDirectly(ogr.Geometry(wkt=str(wkt)))
layer.CreateFeature(feature)
temporary_ds = temporary_dataset(self.dataset.RasterXSize,
self.dataset.RasterYSize,
1,
temp_root=temporary_directory)
# create a temporary raster dataset with the exact same size as the
# dataset to be masked
with temporary_ds as mask_dataset:
band = mask_dataset.GetRasterBand(1)
band.Fill(1)
mask_dataset.SetGeoTransform(self.dataset.GetGeoTransform())
mask_dataset.SetProjection(self.dataset.GetProjection())
# finally rasterize the vector layer to the mask dataset
gdal.RasterizeLayer(mask_dataset, (1, ), layer, burn_values=(0, ))
source_mask_band = mask_dataset.GetRasterBand(1)
self.dataset.CreateMaskBand(gdal.GMF_PER_DATASET)
band = self.dataset.GetRasterBand(1)
mask_band = band.GetMaskBand()
block_x_size, block_y_size = source_mask_band.GetBlockSize()
num_x = source_mask_band.XSize / block_x_size
num_y = source_mask_band.YSize / block_y_size
for x, y in product(range(num_x), range(num_y)):
mask_band.WriteArray(
source_mask_band.ReadAsArray(x * block_x_size,
y * block_y_size,
block_x_size, block_y_size),
x * block_x_size, y * block_y_size)
def connect(self, coverage, data_items, layer, options):
mask_item = data_items[0]
try:
is_reversed = (
layer.metadata.get("eoxs_geometry_reversed") == "true")
except ms.MapServerError:
is_reversed = False
# check if the geometry is "reversed"
if is_reversed:
# TODO: better use the coverages Extent?
geom_types = (ogr.wkbPolygon, ogr.wkbMultiPolygon)
output_polygon = ogr.Geometry(wkt=str(coverage.footprint.wkt))
for mask_item in data_items:
ds = ogr.Open(get_vsi_path(mask_item))
for i in range(ds.GetLayerCount()):
ogr_layer = ds.GetLayer(i)
if not ogr_layer:
continue
feature = ogr_layer.GetNextFeature()
while feature:
# TODO: reproject if necessary
geometry = feature.GetGeometryRef()
if geometry.GetGeometryType() not in geom_types:
continue
if geometry:
output_polygon = output_polygon.Difference(
geometry)
feature = ogr_layer.GetNextFeature()
# since we have the geometry already in memory, add it to the layer
# as WKT
shape = ms.shapeObj.fromWKT(output_polygon.ExportToWkt())
shape.initValues(1)
shape.setValue(0, coverage.identifier)
layer.addFeature(shape)
else:
layer.connectiontype = ms.MS_OGR
layer.connection = connect(data_items[0])
# TODO: more than one mask_item?
layer.setProjection("EPSG:4326")
layer.setMetaData("ows_srs", "EPSG:4326")
layer.setMetaData("wms_srs", "EPSG:4326")
def generate_footprint_wkt(ds, simplification_factor=2):
""" Generate a fooptrint from a raster, using black/no-data as exclusion
"""
# create an empty boolean array initialized as 'False' to store where
# values exist as a mask array.
nodata_map = np.zeros((ds.RasterYSize, ds.RasterXSize), dtype=np.bool)
for idx in range(1, ds.RasterCount + 1):
band = ds.GetRasterBand(idx)
raster_data = band.ReadAsArray()
nodata = band.GetNoDataValue()
if nodata is None:
nodata = 0
# apply the output to the map
nodata_map |= (raster_data != nodata)
# create a temporary in-memory dataset and write the nodata mask
# into its single band
with temporary_dataset(ds.RasterXSize + 2, ds.RasterYSize + 2, 1,
gdal.GDT_Byte) as tmp_ds:
copy_projection(ds, tmp_ds)
tmp_band = tmp_ds.GetRasterBand(1)
tmp_band.WriteArray(nodata_map.astype(np.uint8))
# create an OGR in memory layer to hold the created polygon
sr = osr.SpatialReference()
sr.ImportFromWkt(ds.GetProjectionRef())
ogr_ds = ogr.GetDriverByName('Memory').CreateDataSource('out')
layer = ogr_ds.CreateLayer('poly', sr.sr, ogr.wkbPolygon)
fd = ogr.FieldDefn('DN', ogr.OFTInteger)
layer.CreateField(fd)
# polygonize the mask band and store the result in the OGR layer
gdal.Polygonize(tmp_band, tmp_band, layer, 0)
if layer.GetFeatureCount() != 1:
# if there is more than one polygon, compute the minimum bounding polygon
geometry = ogr.Geometry(ogr.wkbPolygon)
while True:
feature = layer.GetNextFeature()
if not feature:
break
geometry = geometry.Union(feature.GetGeometryRef())
# TODO: improve this for a better minimum bounding polygon
geometry = geometry.ConvexHull()
else:
# obtain geometry from the first (and only) layer
feature = layer.GetNextFeature()
geometry = feature.GetGeometryRef()
if geometry.GetGeometryType() not in (ogr.wkbPolygon, ogr.wkbMultiPolygon):
raise RuntimeError("Error during poligonization. Wrong geometry "
"type.")
# check if reprojection to latlon is necessary
if not sr.IsGeographic():
dst_sr = osr.SpatialReference()
dst_sr.ImportFromEPSG(4326)
try:
geometry.TransformTo(dst_sr.sr)
except RuntimeError:
geometry.Transform(osr.CoordinateTransformation(sr.sr, dst_sr.sr))
gt = ds.GetGeoTransform()
resolution = min(abs(gt[1]), abs(gt[5]))
simplification_value = simplification_factor * resolution
# simplify the polygon. the tolerance value is *really* vague
try:
# SimplifyPreserveTopology() available since OGR 1.9.0
geometry = geometry.SimplifyPreserveTopology(simplification_value)
except AttributeError:
# use GeoDjango bindings if OGR is too old
geometry = ogr.CreateGeometryFromWkt(
GEOSGeometry(geometry.ExportToWkt()).simplify(
simplification_value, True).wkt)
return geometry.ExportToWkt()
def _generate_footprint_wkt(self, ds):
""" Generate a footprint from a raster, using black/no-data as
exclusion
"""
# create an empty boolean array initialized as 'False' to store where
# values exist as a mask array.
nodata_map = numpy.zeros((ds.RasterYSize, ds.RasterXSize),
dtype=numpy.bool)
for idx in range(1, ds.RasterCount + 1):
band = ds.GetRasterBand(idx)
raster_data = band.ReadAsArray()
nodata = band.GetNoDataValue()
if nodata is None:
nodata = 0
# apply the output to the map
nodata_map |= (raster_data != nodata)
# create a temporary in-memory dataset and write the nodata mask
# into its single band
tmp_ds = create_mem(ds.RasterXSize + 2, ds.RasterYSize + 2, 1,
gdal.GDT_Byte)
copy_projection(ds, tmp_ds)
tmp_band = tmp_ds.GetRasterBand(1)
tmp_band.WriteArray(nodata_map.astype(numpy.uint8))
# Remove unwanted small areas of nodata
# www.gdal.org/gdal__alg_8h.html#a33309c0a316b223bd33ae5753cc7f616
no_pixels = tmp_ds.RasterXSize * tmp_ds.RasterYSize
threshold = 4
max_threshold = (no_pixels / 16)
if self.sieve_max_threshold > 0:
max_threshold = self.sieve_max_threshold
while threshold <= max_threshold and threshold < 2147483647:
gdal.SieveFilter(tmp_band, None, tmp_band, threshold, 4)
threshold *= 4
#for debugging:
#gdal.GetDriverByName('GTiff').CreateCopy('/tmp/test.tif', tmp_ds)
# create an OGR in memory layer to hold the created polygon
sr = osr.SpatialReference()
sr.ImportFromWkt(ds.GetProjectionRef())
ogr_ds = ogr.GetDriverByName('Memory').CreateDataSource('out')
layer = ogr_ds.CreateLayer('poly', sr, ogr.wkbPolygon)
fd = ogr.FieldDefn('DN', ogr.OFTInteger)
layer.CreateField(fd)
# polygonize the mask band and store the result in the OGR layer
gdal.Polygonize(tmp_band, tmp_band, layer, 0)
tmp_ds = None
if layer.GetFeatureCount() > 1:
# if there is more than one polygon, compute the minimum
# bounding polygon
logger.debug("Merging %s features in footprint." %
layer.GetFeatureCount())
# union all features in one multi-polygon
geometry = ogr.Geometry(ogr.wkbMultiPolygon)
while True:
feature = layer.GetNextFeature()
if not feature:
break
geometry.AddGeometry(feature.GetGeometryRef())
geometry = geometry.UnionCascaded()
# TODO: improve this for a better minimum bounding polygon
geometry = geometry.ConvexHull()
elif layer.GetFeatureCount() < 1:
# there was an error during polygonization
raise RuntimeError("Error during polygonization. No feature "
"obtained.")
else:
# obtain geometry from the first (and only) layer
feature = layer.GetNextFeature()
geometry = feature.GetGeometryRef()
if geometry.GetGeometryType() != ogr.wkbPolygon:
raise RuntimeError(
"Error during polygonization. Wrong geometry "
"type: %s" %
ogr.GeometryTypeToName(geometry.GetGeometryType()))
# check if reprojection to latlon is necessary
if not sr.IsGeographic():
dst_sr = osr.SpatialReference()
dst_sr.ImportFromEPSG(4326)
try:
geometry.TransformTo(dst_sr)
except RuntimeError:
geometry.Transform(osr.CoordinateTransformation(sr, dst_sr))
gt = ds.GetGeoTransform()
resolution = min(abs(gt[1]), abs(gt[5]))
simplification_value = self.simplification_factor * resolution
#for debugging:
#geometry.GetGeometryRef(0).GetPointCount()
# simplify the polygon. the tolerance value is *really* vague
try:
# SimplifyPreserveTopology() available since OGR 1.9.0
geometry = geometry.SimplifyPreserveTopology(simplification_value)
except AttributeError:
# use GeoDjango bindings if OGR is too old
geometry = ogr.CreateGeometryFromWkt(
GEOSGeometry(geometry.ExportToWkt()).simplify(
simplification_value, True).wkt)
return geometry.ExportToWkt()
