def makeRidgeRaster(self):
"""Make raster to show ridges."""
ridgeFile = QSWATUtils.join(self._gv.demDir,
'ridge' + str(self.branchThresh) + '.tif')
ridgeRaster = Raster(ridgeFile, self._gv, canWrite=True, isInt=True)
res = ridgeRaster.open(self.chunkCount,
numRows=self.numRows,
numCols=self.numCols,
transform=self.demTransform,
projection=self.demProjection,
noData=self.noData)
if not res:
return
for row in range(self.numRows):
for col in range(self.numCols):
if self.demRaster.read(row, col) != self.demNoData:
val, _ = self.ridgePoints.get((row, col), (-1, -1))
ridgeRaster.write(row, col, 0 if val == -1 else 1)
ridgeRaster.close()
class Floodplain(QObject):
"""
Calculate floodplain raster from DEM, stream threshold, ridge threshold, floodplain threshold,
(optionally) D8 flow direction grid, flow accumulation grid, outlets shapefile.
The slope position value is, for each point, (e - v) / (r - v) where e is the elevation,
v the nearest valley floor elevation, and r the nearest ridge elevation. Nearest means along D8 flow path.
Valley floor is points with flow accumulation above stream generation threshold.
Ridge is similar, obtained by inverting DEM, then calculating D8 flow direction and accumulation.
The floodplain raster is zero for points with slope position value at most the floodplain threshold, else 1.
"""
def __init__(self, gv, progress, chunkCount):
"""Initialise class variables."""
QObject.__init__(self)
self._gv = gv
self._progress = progress
## raster chunk count
self.chunkCount = chunkCount
## ridge accumulation threshold
self.ridgeThresh = 0
## floodplain accumulation threshold
self.floodThresh = 0
## branch length threshold
self.branchThresh = 0
## dem raster dataset
self.demDs = None
## dem raster transform
self.demTransform = None
## dem raster
self.demRaster = None
## dem raster no data value
self.demNoData = -1
## dem raster projection
self.demProjection = None
## no data value for output rasters; must be negative
self.noData = -1
## number of rows in input clipped DEM raster
self.numRows = 0
## number of columns in input clipped DEM raster
self.numCols = 0
## depths of valley floor below points
self.valleyDepthsRaster = None
## file path for ridgeHeightsRaster
self.ridgeHeightsFile = ''
## heights of ridge above points
self.ridgeHeightsRaster = None
## distances of ridge from points
self.ridgeDistancesRaster = None
## floodplain raster
self.floodplainRaster = None
## flag to indicate if using inversion or branch length method
self.useInversion = True
## map of (row, col) to (elevation, branch length) for ridge points
self.ridgePoints = None
def run(self, demRaster, valleyDepthsFile, ridgeThresh, floodThresh,
branchThresh, subbasins, distances, slopeDir, flowAcc, ridgep,
ridges, noData, mustRun):
"""
Generate floodplain raster , with floodplain value 0 and upland value 1.
valleyDepthsRaster is already calculated and stored in valleyDepthsFile
ridgeThresh is the threshold in pixel counts for ridges (inverse accumulation).
floodThresh is the critical ratio of relative depth of valley floor against height of ridge above valley floor.
branchThresh is the threshold in metres for branch lengths.
dem is clipped filled DEM
The groups {subbasins, distances, slopeDir, flowAcc} and {ridgep, ridges} are either all None or all existing files,
assumed to be clipped and with same pixel size as DEM (so (row, col|) coordinates may be shared across all of them).
The second group is used to calculate ridges by DEM inversion if subbasins is None, else the first is used to
calculate ridges by branch lengths.
"""
self.demRaster = demRaster
self.ridgeThresh = ridgeThresh
self.floodThresh = floodThresh
self.branchThresh = branchThresh
gdal.AllRegister()
ds = self.demRaster.ds
self.numRows = ds.RasterYSize
self.numCols = ds.RasterXSize
self.demTransform = ds.GetGeoTransform()
self.demNoData = self.demRaster.band.GetNoDataValue()
self.demProjection = ds.GetProjection()
self.noData = noData
self._progress('Ridge heights ...')
root = QgsProject.instance().layerTreeRoot()
if subbasins is None:
# use inverted DEM method for ridges
self.useInversion = True
time1 = time.process_time()
if not self.calcRidgeHeightsByInversion(ridgep, ridges, root,
mustRun):
return
time2 = time.process_time()
QSWATUtils.loginfo(
'Ridge heights by inversion took {0} seconds'.format(
int(time2 - time1)))
else:
self.useInversion = False
time1 = time.process_time()
if not self.calRidgeHeghtsByBranchLength(
subbasins, distances, slopeDir, flowAcc, valleyDepthsFile,
root, mustRun):
return
time2 = time.process_time()
QSWATUtils.loginfo(
'Ridge heights by branch length took {0} seconds'.format(
int(time2 - time1)))
time1 = time.process_time()
self.writeFloodPlain(valleyDepthsFile, mustRun)
time2 = time.process_time()
QSWATUtils.loginfo('Floodplain creation took {0} seconds'.format(
int(time2 - time1)))
self._progress('')
def calcRidgeHeightsByInversion(self, ridgep, ridges, root, mustRun):
"""
Create the ridgeHeightsRaster with differences between the elevation at the point and
the elevation of the nearest ridge cell.
ridgep is the D8 flow directions and ridges the flow accumulation raster , both calculated from an inverted DEM.
"""
self.ridgeHeightsFile = QSWATUtils.join(self._gv.demDir,
'invheights.tif')
if mustRun or not QSWATUtils.isUpToDate(
ridgep, self.ridgeHeightsFile) or not QSWATUtils.isUpToDate(
ridges, self.ridgeHeightsFile):
self._gv.clearOpenRasters()
completed = False
while not completed:
try:
completed = True # only gets set on MemoryError exception
if os.path.exists(self.ridgeHeightsFile):
QSWATUtils.tryRemoveLayerAndFiles(
self.ridgeHeightsFile, root)
self.ridgeHeightsRaster = Raster(self.ridgeHeightsFile,
self._gv,
canWrite=True,
isInt=False)
res = self.ridgeHeightsRaster.open(
self.chunkCount,
numRows=self.numRows,
numCols=self.numCols,
transform=self.demTransform,
projection=self.demProjection,
noData=self.noData)
if not res:
return False
# ridgep obtained by inversion has float values, although these are in the range 1 to 8
ridgepRaster = Raster(ridgep,
self._gv,
canWrite=False,
isInt=False)
res = ridgepRaster.open(self.chunkCount)
if not res:
self._gv.closeOpenRasters()
return False
ridgesRaster = Raster(ridges,
self._gv,
canWrite=False,
isInt=True)
res = ridgesRaster.open(self.chunkCount)
if not res:
self._gv.closeOpenRasters()
return False
for row in range(self.numRows):
for col in range(self.numCols):
if self.demRaster.read(row, col) != self.demNoData:
(val, path) = self.valueAtNearest(
row, col, ridgepRaster, ridgesRaster,
self.ridgeThresh)
if path is not None:
self.propagate(val, path)
ridgepRaster.close()
ridgesRaster.close()
self.ridgeHeightsRaster.close()
return True
except MemoryError:
QSWATUtils.loginfo(
'Out of memory for ridge heights by inversion with chunk count {0}'
.format(self.chunkCount))
self._gv.closeOpenRasters()
completed = False
self.chunkCount += 1
if not self.demRaster.open(self.chunkCount):
return False
else:
return True
def calRidgeHeghtsByBranchLength(self, subbasins, distances, slopeDir,
flowAcc, valleyDepthsFile, root, mustRun):
"""
Create the ridgeHeightsRaster with differences between the elevation at the point and
the elevation of the nearest ridge cell.
subbasins is the subbasins raster, distances is the distances to outlet raster,
slopeDir is the D8 slope directions raster, flowAcc the flow accumulation raster, all four clipped
the same as the DEM.
valleyDepthsFile is the existing raster giving the depth of the valley flow below each point (as a positive number of metres).
"""
self.ridgeHeightsFile = QSWATUtils.join(self._gv.demDir,
'branchheights.tif')
distancesFile = QSWATUtils.join(self._gv.demDir,
'branchdistancess.tif')
if mustRun or not QSWATUtils.isUpToDate(subbasins, self.ridgeHeightsFile) \
or not QSWATUtils.isUpToDate(distances, self.ridgeHeightsFile) \
or not QSWATUtils.isUpToDate(slopeDir, self.ridgeHeightsFile) \
or not QSWATUtils.isUpToDate(flowAcc, self.ridgeHeightsFile):
self._gv.clearOpenRasters()
completed = False
while not completed:
try:
completed = True # only gets set on MemoryError exception
if os.path.exists(self.ridgeHeightsFile):
QSWATUtils.tryRemoveLayerAndFiles(
self.ridgeHeightsFile, root)
if os.path.exists(distancesFile):
QSWATUtils.tryRemoveLayerAndFiles(distancesFile, root)
self.ridgeHeightsRaster = Raster(self.ridgeHeightsFile,
self._gv,
canWrite=True,
isInt=False)
res = self.ridgeHeightsRaster.open(
self.chunkCount,
numRows=self.numRows,
numCols=self.numCols,
transform=self.demTransform,
projection=self.demProjection,
noData=self.noData)
if not res:
return False
self.ridgeDistancesRaster = Raster(distancesFile,
self._gv,
canWrite=True,
isInt=False)
res = self.ridgeDistancesRaster.open(
self.chunkCount,
numRows=self.numRows,
numCols=self.numCols,
transform=self.demTransform,
projection=self.demProjection,
noData=self.noData)
if not res:
self._gv.closeOpenRasters()
return False
subbasinsRaster = Raster(subbasins,
self._gv,
canWrite=False,
isInt=True)
res = subbasinsRaster.open(self.chunkCount)
if not res:
self._gv.closeOpenRasters()
return False
distRaster = Raster(distances,
self._gv,
canWrite=False,
isInt=False)
res = distRaster.open(self.chunkCount)
if not res:
self._gv.closeOpenRasters()
return False
self.findRidges(subbasinsRaster, distRaster, root)
subbasinsRaster.close()
distRaster.close()
accRaster = Raster(flowAcc,
self._gv,
canWrite=False,
isInt=True)
res = accRaster.open(self.chunkCount)
if not res:
self._gv.closeOpenRasters()
return False
dirRaster = Raster(slopeDir,
self._gv,
canWrite=False,
isInt=True)
res = dirRaster.open(self.chunkCount)
if not res:
self._gv.closeOpenRasters()
return False
self.propagateFromRidges(valleyDepthsFile, dirRaster,
accRaster)
dirRaster.close()
accRaster.close()
self.ridgeHeightsRaster.close()
self.ridgeDistancesRaster.close()
return True
except MemoryError:
QSWATUtils.loginfo(
'Out of memory for ridge heights by branch length with chunk count {0}'
.format(self.chunkCount))
self._gv.closeOpenRasters()
completed = False
self.chunkCount += 1
if not self.demRaster.open(self.chunkCount):
return False
else:
return True
def valueAtNearest(self, row, col, d8Raster, accRaster, threshold):
"""
Return the positive elevation of the nearest point in accRaster where it is at least threshold,
plus path along d8Raster to that point.
If a value is found in result, point already processed, return result - elevation for that point.
We are working upslope, final height is ridge height,
ridgeHeights contains ridge - elev, i.e. positive height of ridge above point,
so if result already exists, ridge is recovered as result + elev
"""
path = []
accNoData = accRaster.band.GetNoDataValue()
while True:
res = self.ridgeHeightsRaster.read(row, col)
if res >= 0: # already done this point
# eg result is 60, this point's elevation is 100, return value (ridge elevation) is 160
return (self.demRaster.read(row, col) + res, path)
acc = accRaster.read(row, col)
if acc >= threshold or acc == accNoData: # found nearest stopping point
path.append((row, col))
return (self.demRaster.read(row, col), path)
if (row, col) in path:
(startRow, startCol) = path[0]
startX, startY = QSWATTopology.cellToProj(
startCol, startRow, self.demTransform)
x, y = QSWATTopology.cellToProj(col, row, self.demTransform)
QSWATUtils.error(
'Loop to ({0}, {1}) from ({2}, {3})'.format(
x, y, startX, startY), self._gv.isBatch)
return (0, None)
path.append((row, col))
pt, _ = self.alongDirPoint(row, col, d8Raster)
if pt is None:
# hit edge of clipped area = must be a ridge
return (self.demRaster.read(row, col), path)
(row, col) = pt
def propagate(self, val, path):
"""
For each point on path, set result to val (ridge elevation) - point elevation."""
for (row, col) in path:
self.ridgeHeightsRaster.write(row, col,
val - self.demRaster.read(row, col))
def writeFloodPlain(self, valleyDepthsFile, mustRun):
"""Calculate slope positions from valleyDepths and ridgeHeights, and write floodplain raster ."""
method = 'inv' if self.useInversion else 'branch'
thresh = '{0:.2F}'.format(self.floodThresh).replace('.', '_')
flood = QSWATUtils.join(self._gv.floodDir,
method + 'flood' + thresh + '.tif')
root = QgsProject.instance().layerTreeRoot()
if mustRun or \
not QSWATUtils.isUpToDate(valleyDepthsFile, flood) or \
not QSWATUtils.isUpToDate(self.ridgeHeightsFile, flood):
if os.path.exists(flood):
QSWATUtils.tryRemoveLayerAndFiles(flood, root)
self._gv.clearOpenRasters()
completed = False
while not completed:
try:
completed = True # only gets set on MemoryError exception
self.ridgeHeightsRaster = Raster(self.ridgeHeightsFile,
self._gv,
canWrite=False,
isInt=False)
res = self.ridgeHeightsRaster.open(self.chunkCount)
if not res:
self._gv.closeOpenRasters()
return
if self.valleyDepthsRaster is None:
# may have been opened when calculating ridge heights by branch length
self.valleyDepthsRaster = Raster(valleyDepthsFile,
self._gv,
canWrite=False,
isInt=False)
res = self.valleyDepthsRaster.open(self.chunkCount)
if not res:
self._gv.closeOpenRasters()
return
self._progress('Flood plain...')
self.floodplainRaster = Raster(flood,
self._gv,
canWrite=True,
isInt=True)
OK = self.floodplainRaster.open(
self.chunkCount,
numRows=self.numRows,
numCols=self.numCols,
transform=self.demTransform,
projection=self.demProjection,
noData=self.noData)
if OK:
self.calcFloodPlain1()
self.floodplainRaster.close()
## fixing aux.xml file seems unnecessary in QGIS 2.16
# # now fix maximum value to 1 instead of zero in aux.xml file
# # else if loaded has legend 0 to nan and display is all black
# xmlFile = self.floodplainRaster.fileName + '.aux.xml'
# ok, err = QSWATUtils.setXMLValue(xmlFile, u'MDI', u'key', u'STATISTICS_MAXIMUM', u'1')
# if not ok:
# QSWATUtils.error(err, self._gv.isBatch)
QSWATUtils.copyPrj(self.demRaster.fileName,
self.floodplainRaster.fileName)
# load flood above DEM
layers = root.findLayers()
demLayer = QSWATUtils.getLayerByLegend(
FileTypes.legend(FileTypes._DEM), layers)
ft = FileTypes._INVFLOOD if self.useInversion else FileTypes._BRANCHFLOOD
floodLayer, _ = QSWATUtils.getLayerByFilename(
layers, self.floodplainRaster.fileName, ft,
self._gv, demLayer,
QSWATUtils._WATERSHED_GROUP_NAME)
if floodLayer is None:
QSWATUtils.error('Failed to load floodplain raster {0}' \
.format(self.floodplainRaster.fileName), self._gv.isBatch)
self.valleyDepthsRaster.close()
self.ridgeHeightsRaster.close()
self._progress('Flood plain done')
except MemoryError:
QSWATUtils.loginfo(
'Out of memory for flood plain with chunk count {0}'.
format(self.chunkCount))
self._gv.closeOpenRasters()
completed = False
self.chunkCount += 1
else: # already have uptodate flood file: make sure it is loaded
# load flood above DEM
layers = root.findLayers()
demLayer = QSWATUtils.getLayerByLegend(
FileTypes.legend(FileTypes._DEM), layers)
ft = FileTypes._INVFLOOD if self.useInversion else FileTypes._BRANCHFLOOD
floodLayer, _ = QSWATUtils.getLayerByFilename(
layers, flood, ft, self._gv, demLayer,
QSWATUtils._WATERSHED_GROUP_NAME)
if floodLayer is None:
QSWATUtils.error('Failed to load floodplain raster {0}' \
.format(self.floodplainRaster.fileName), self._gv.isBatch)
def calcFloodPlain1(self):
"""Calculate the floodplain array elementwise."""
old_settings = numpy.seterr(divide='raise')
valleyTransform = self.valleyDepthsRaster.ds.GetGeoTransform()
for row in range(self.numRows):
for col in range(self.numCols):
rh = self.ridgeHeightsRaster.read(row, col)
if rh != self.noData:
vd = self.valleyDepthsRaster.read(row, col)
if vd != self.noData:
try:
sp = 0 if int(rh + vd) == 0 else vd / (rh + vd)
except Exception:
QSWATUtils.information('Problem in calculating slope position at {0}: numerator {1}; denominator {2}: {3}. Set to 0' \
.format(QSWATTopology.cellToProj(col, row, valleyTransform), vd, rh+vd, traceback.format_exc()),
self._gv.isBatch)
sp = 0
self.floodplainRaster.write(
row, col,
1 if sp <= self.floodThresh else self.noData)
numpy.seterr(divide=old_settings['divide'])
# TODO: deal with array access
#===========================================================================
# def calcFloodPlain2(self):
# """Calculate the floodplain array using numpy array methods."""
# for i in xrange(self.chunkCount):
# # if there is only one chunk we can avoid reading it again
# if i != self.ridgeHeightsRaster.currentIndex:
# heightsChunk = self.ridgeHeightsRaster.chunks[i]
# self.ridgeHeightsRaster.array = self.ridgeHeightsRaster.band.ReadAsArray(0, heightsChunk.rowOffset, self.ridgeHeightsRaster.numCols, heightsChunk.numRows)
# self.ridgeHeightsRaster.currentIndex = i
# if i != self.valleyDepthsRaster.currentIndex:
# depthsChunk = self.valleyDepthsRaster.chunks[i]
# self.valleyDepthsRaster.array = self.valleyDepthsRaster.band.ReadAsArray(0, depthsChunk.rowOffset, self.valleyDepthsRaster.numCols, depthsChunk.numRows)
# self.valleyDepthsRaster.currentIndex = i
# msk = (self.ridgeHeightsRaster.array != self.noData) & (self.valleyDepthsRaster.array() != self.noData)
# # start with array of right size for floodplain (since current size will be last initial chunk which may be small)
# # note also we have to initialize it to type float and correct to int later
# floodplainChunk = self.floodplainRaster.chunks[i]
# self.floodplainRaster.array = np.core.full((floodplainChunk.numRows, self.numCols), self.noData, np.float_)
# # the next line uses just one write but does not work
# #self.floodplainRaster.array[msk] = 1 if (self.valleyDepthsRaster.array[msk] / (self.valleyDepthsRaster.array[msk] + self.ridgeHeightsRaster.array[msk])) <= self.floodThresh else 0
# self.floodplainRaster.array[msk] = self.valleyDepthsRaster.array[msk] / (self.valleyDepthsRaster.array[msk] + self.ridgeHeightsRaster.array[msk])
# self.floodplainRaster.array[(self.floodplainRaster.array > self.floodThresh) & (self.ridgeHeightsRaster.array != self.noData) & (self.valleyDepthsRaster.array != self.noData)] = 1
# self.floodplainRaster.array[(self.floodplainRaster.array <= self.floodThresh) & (self.ridgeHeightsRaster.array != self.noData) & (self.valleyDepthsRaster.array != self.noData)] = 2
# self.floodplainRaster.array[msk] = self.floodplainRaster.array[msk] - 1
# self.floodplainRaster.array = self.floodplainRaster.array.astype(np.int_)
# self.floodplainRaster.array[self.floodplainRaster.array < 0] = self.noData
# self.floodplainRaster.band.WriteArray(self.floodplainRaster.array, 0, floodplainChunk.rowOffset)
#===========================================================================
def findRidges(self, subbasinsRaster, distRaster, root):
"""
Create ridge points dictionary (row, col) -> (elevation, maximum branch length) for all cells on
subbasin boundaries.
A cell is on a boundary if it has one or more adjacent cells in a different subbasin,
or if it has an adjacent cell with nodata for its subbasin, ie it is on watershed boundary,
when its branch length is set to the branch threshold.
The maximum branch length is the maximum of the branch lengths for adjacent cells
that are in a different subbasin or outside the watershed.
Assumes subbasins, outlet distance and dem rasters have same extents and cell sizes.
"""
# check assumption about rasters:
assert self.demTransform == subbasinsRaster.ds.GetGeoTransform(
), 'DEM and subbasins rasters not compatible'
assert self.demTransform == distRaster.ds.GetGeoTransform(
), 'DEM and distance to outlet rasters not compatible'
if len(self._gv.topo.subbasinToStream) == 0:
# need to calculate some topology
if self._gv.useGridModel:
if os.path.exists(self._gv.delinStreamFile):
streamLayer = QgsVectorLayer(self._gv.delinStreamFile,
'Delineated streams', 'ogr')
else:
QSWATUtils.error(
'Cannot use branch length algorithm without a delineated stream shapefile',
self._gv.isBatch)
return
else:
streamLayer = QSWATUtils.getLayerByFilename(
root.findLayers(), self._gv.streamFile, FileTypes._STREAMS,
None, None, None)[0]
if streamLayer is None:
QSWATUtils.error(
'Streams layer not found: have you run TauDEM?',
self._gv.isBatch)
return
if not self._gv.topo.setUp1(streamLayer):
return
self.makeRidges(subbasinsRaster, distRaster)
time1 = time.process_time()
self.makeRidgeRaster()
time2 = time.process_time()
QSWATUtils.loginfo('Writing ridge raster took {0} seconds'.format(
int(time2 - time1)))
def makeRidges(self, subbasinsRaster, distRaster):
"""
Set values of ridge points.
"""
time1 = time.process_time()
self.ridgePoints = dict()
subbasinsNoData = subbasinsRaster.band.GetNoDataValue()
for row in range(self.numRows):
for col in range(self.numCols):
subbasin = subbasinsRaster.read(row, col)
if subbasin == subbasinsNoData:
continue
maxBranchLength = 0
finished = False
for dy in [-1, 0, 1]:
row1 = row + dy
dxs = [-1, 1] if dy == 0 else [-1, 0, 1]
for dx in dxs:
col1 = col + dx
if self.pointInMap(row1, col1):
subbasin1 = subbasinsRaster.read(
row + dy, col + dx)
else:
subbasin1 = subbasinsNoData
if subbasin1 == subbasinsNoData:
maxBranchLength = self.branchThresh
finished = True
break
elif subbasin1 != subbasin:
distanceToJoin = self._gv.topo.getDistanceToJoin(
subbasin1, subbasin)
branchLength = distRaster.read(
row1, col1) + distanceToJoin
maxBranchLength = max(branchLength,
maxBranchLength)
if finished:
break
if maxBranchLength >= self.branchThresh:
elevation = self.demRaster.read(row, col)
if elevation != self.demNoData:
self.ridgePoints[(row, col)] = (elevation,
maxBranchLength)
time2 = time.process_time()
QSWATUtils.loginfo('Making ridge points took {0} seconds'.format(
int(time2 - time1)))
def getRidgeElevation(self, row, col, reportFailure):
"""
Find nearest ridge point to (row, col) and return its elevation and distance from (row, col).
Distance is cartesian distance, in number of pixels (assumed square).
Algorithm looks for first acceptable ridge point on increasing square perimeter around original point,
as an approximation to the nearest.
Slope position algorithm for floodplain identification only depends on elevations, not distances,
so we don't worry too much about distances to ridge points, and interpret 'nearest' loosely for efficient execution.
"""
# use view so that changes may be used later in iteration, and avoid repeated searches for adjacent unacceptable points
n = 0
while True:
#=============version where square used has N-s and E-W sides=======
# for dy in xrange(0-n, n+1):
# for dx in xrange(0-n, n+1):
# if abs(dy) == n or abs(dx) == n: # on boundary of square
# (e, l) = self.ridgePoints.get((row+dy, col+dx), (-1, -1))
# if l >= 0:
# return e, math.sqrt(dx * dx + dy * dy)
#===================================================================
# version with diagonal sides to square - a little closer to circular maybe?
if n == 0:
(e, l) = self.ridgePoints.get((row, col), (-1, -1))
if l >= 0:
return e, 0
else:
for dx in range(n + 1):
dy = n - dx
(e, l) = self.ridgePoints.get((row + dy, col + dx),
(-1, -1))
if l >= 0:
return e, math.sqrt(dx * dx + dy * dy)
if dx != 0:
(e, l) = self.ridgePoints.get((row + dy, col - dx),
(-1, -1))
if l >= 0:
return e, math.sqrt(dx * dx + dy * dy)
if dy != 0:
(e, l) = self.ridgePoints.get((row - dy, col + dx),
(-1, -1))
if l >= 0:
return e, math.sqrt(dx * dx + dy * dy)
if dx != 0:
(e, l) = self.ridgePoints.get((row - dy, col - dx),
(-1, -1))
if l >= 0:
return e, math.sqrt(dx * dx + dy * dy)
n += 1
if n > 1000:
if reportFailure:
x, y = QSWATTopology.cellToProj(row, col,
self.demTransform)
QSWATUtils.information(
'No ridge point found within 1000 pixels of ({0}, {1}). Is the branch threshold too high?'
.format(x, y), self._gv.isBatch)
return 0, -1
def propagateFromRidges(self, valleyDepthsFile, dirRaster, accRaster):
"""
Propagate relative heights of nearest ridge points along flow paths, starting from points with accumulation 1.
Heights are put into ridgeHeightsRaster.
Distances from ridge are put into ridgeDistancesRaster If a point already has a height,
but the new path is shorter, the new height overwrites the old.
"""
time1 = time.process_time()
self.valleyDepthsRaster = Raster(valleyDepthsFile,
self._gv,
canWrite=False,
isInt=False)
res = self.valleyDepthsRaster.open(self.chunkCount)
if not res:
return
reportFailure = True
pathLength = 0 # path length counted in pixels (horizontal and vertical assumed same, so 1)
diag = math.sqrt(2)
for row in range(self.numRows):
for col in range(self.numCols):
if accRaster.read(row, col) == 1:
elevation, pathLength = self.getRidgeElevation(
row, col, reportFailure)
if pathLength < 0:
if reportFailure:
reportFailure = False
elevation = self.demRaster.read(row, col)
pathLength = 0
nextRow, nextCol = row, col
while True:
nextElev = self.demRaster.read(nextRow, nextCol)
if nextElev == self.demNoData:
break
currentPathLength = self.ridgeDistancesRaster.read(
nextRow, nextCol)
if currentPathLength >= 0:
# have a previously stored value
if pathLength < currentPathLength:
# new path length from ridge is shorter: update heights raster
self.ridgeHeightsRaster.write(
nextRow, nextCol, elevation - nextElev)
self.ridgeDistancesRaster.write(
nextRow, nextCol, pathLength)
else: # already had shorter path from ridge - no point in continuing down flow path
break
else: # no value stored yet
self.ridgeHeightsRaster.write(
nextRow, nextCol, elevation - nextElev)
self.ridgeDistancesRaster.write(
nextRow, nextCol, pathLength)
pt, isDiag = self.alongDirPoint(
nextRow, nextCol, dirRaster)
if pt is None:
break
pathLength += diag if isDiag else 1
nextRow, nextCol = pt
time2 = time.process_time()
QSWATUtils.loginfo('Propagating ridge points took {0} seconds'.format(
int(time2 - time1)))
def makeRidgeRaster(self):
"""Make raster to show ridges."""
ridgeFile = QSWATUtils.join(self._gv.demDir,
'ridge' + str(self.branchThresh) + '.tif')
ridgeRaster = Raster(ridgeFile, self._gv, canWrite=True, isInt=True)
res = ridgeRaster.open(self.chunkCount,
numRows=self.numRows,
numCols=self.numCols,
transform=self.demTransform,
projection=self.demProjection,
noData=self.noData)
if not res:
return
for row in range(self.numRows):
for col in range(self.numCols):
if self.demRaster.read(row, col) != self.demNoData:
val, _ = self.ridgePoints.get((row, col), (-1, -1))
ridgeRaster.write(row, col, 0 if val == -1 else 1)
ridgeRaster.close()
#QSWATUtils.getLayerByFilename(self._iface.legendInterface().layers(), ridgeFile, FileTypes._OTHER,
# self._gv, None, QSWATUtils._WATERSHED_GROUP_NAME)
def alongDirPoint(self, row, col, d8Raster):
"""Return next point (as pair or None) along d8Raster direction from (row, col) that has a data value in demRaster."""
# d8Raster obtained by inverting the d8 flow directions raster has float values, so must cooerce to int
dir0 = int(d8Raster.read(row, col) - 1)
if 0 <= dir0 < 8:
row1 = row + QSWATUtils._dY[dir0]
col1 = col + QSWATUtils._dX[dir0]
if self.pointInMap(row1, col1) and self.demRaster.read(
row1, col1) != self.demNoData:
isDiag = (dir0 // 2 == 1)
return (row1, col1), isDiag
else:
return None, False
else:
return None, False
def pointInMap(self, row, col):
"""Return true if row and col are in the limits for the DEM array."""
return 0 <= row < self.numRows and 0 <= col < self.numCols
