"""

Algorithm to densify lines and polygons using geodesic calculations.

"""

# Constants used to refer to parameters and outputs. They will be

# used when calling the algorithm from another algorithm, or when

# calling from the QGIS console.

PrmInputLayer = 'InputLayer'

PrmOutputLayer = 'OutputLayer'

PrmDiscardVertices = 'DiscardVertices'

PrmMaxSegmentLength = 'MaxSegmentLength'

def initAlgorithm(self, config):

self.addParameter(

QgsProcessingParameterFeatureSource(

self.PrmInputLayer,

tr('Line or polygon layer'),

[QgsProcessing.TypeVectorLine, QgsProcessing.TypeVectorPolygon])

)

self.addParameter(

QgsProcessingParameterBoolean(

self.PrmDiscardVertices,

tr('Discard inner vertices (lines only)'),

False,

optional=True)

)

self.addParameter(

QgsProcessingParameterNumber(

self.PrmMaxSegmentLength,

tr('Maximum line segment length (in kilometers)'),

QgsProcessingParameterNumber.Double,

defaultValue=settings.maxSegLength,

minValue=0.001,

optional=True)

)

self.addParameter(

QgsProcessingParameterFeatureSink(

self.PrmOutputLayer,

tr('Output layer'))

)

def processAlgorithm(self, parameters, context, feedback):

source = self.parameterAsSource(parameters, self.PrmInputLayer, context)

discardVertices = self.parameterAsBool(parameters, self.PrmDiscardVertices, context)

maxseglen = self.parameterAsDouble(parameters, self.PrmMaxSegmentLength, context) * 1000 # Make it in meters

wkbtype = source.wkbType()

if wkbtype == QgsWkbTypes.LineString or wkbtype == QgsWkbTypes.MultiLineString:

outputType = QgsWkbTypes.LineString if (

wkbtype == QgsWkbTypes.LineString or discardVertices) else QgsWkbTypes.MultiLineString

(sink, dest_id) = self.parameterAsSink(

parameters, self.PrmOutputLayer,

context, source.fields(), outputType, source.sourceCrs())

num_bad = processLine(source, sink, feedback, discardVertices, maxseglen)

else:

outputType = QgsWkbTypes.Polygon if wkbtype == QgsWkbTypes.Polygon else QgsWkbTypes.MultiPolygon

(sink, dest_id) = self.parameterAsSink(

parameters, self.PrmOutputLayer,

context, source.fields(), outputType, source.sourceCrs())

num_bad = processPoly(source, sink, feedback, maxseglen)

if num_bad > 0:

feedback.pushInfo(tr("{} out of {} features from input layer failed to process correctly.".format(num_bad, source.featureCount())))

return {self.PrmOutputLayer: dest_id}

def name(self):

return 'geodesicdensifier'

def icon(self):

return QIcon(os.path.dirname(__file__) + '/images/geodesicDensifier.svg')

def displayName(self):

return tr('Geodesic densifier')

def group(self):

return tr('Vector geometry')

def groupId(self):

return 'vectorgeometry'

def helpUrl(self):

file = os.path.dirname(__file__) + '/index.html'

if not os.path.exists(file):

return ''

return QUrl.fromLocalFile(file).toString(QUrl.FullyEncoded)

def shortHelpString(self):

file = os.path.dirname(__file__) + '/doc/GeodesicDensifyAlgorithm.help'

if not os.path.exists(file):

return ''

with open(file) as helpf:

help = helpf.read()

return help

def createInstance(self):

layercrs = source.sourceCrs()

if layercrs != epsg4326:

transto4326 = QgsCoordinateTransform(layercrs, epsg4326, QgsProject.instance())

transfrom4326 = QgsCoordinateTransform(epsg4326, layercrs, QgsProject.instance())

total = 100.0 / source.featureCount() if source.featureCount() else 0

iterator = source.getFeatures()

num_bad = 0

for cnt, feature in enumerate(iterator):

if feedback.isCanceled():

break

try:

if not feature.geometry().isMultipart():

poly = feature.geometry().asPolygon()

numpolygons = len(poly)

if numpolygons < 1:

continue

ptset = []

# Iterate through all points in the polygon and if the distance

# is greater than the maxseglen, then add additional points.

for points in poly:

numpoints = len(points)

if numpoints < 2:

continue

# If the input is not 4326 we need to convert it to that and then back to the output CRS

ptStart = QgsPointXY(points[0][0], points[0][1])

if layercrs != epsg4326: # Convert to 4326

ptStart = transto4326.transform(ptStart)

pts = [ptStart]

for x in range(1, numpoints):

ptEnd = QgsPointXY(points[x][0], points[x][1])

if layercrs != epsg4326: # Convert to 4326

ptEnd = transto4326.transform(ptEnd)

gline = geod.InverseLine(ptStart.y(), ptStart.x(), ptEnd.y(), ptEnd.x())

# Check to see if the distance is greater than the maximum

# segment length and if so lets add additional points.

if gline.s13 > maxseglen:

n = int(math.ceil(gline.s13 / maxseglen))

seglen = gline.s13 / n

for i in range(1, n):

s = seglen * i

g = gline.Position(s, Geodesic.LATITUDE | Geodesic.LONGITUDE | Geodesic.LONG_UNROLL)

pts.append(QgsPointXY(g['lon2'], g['lat2']))

pts.append(ptEnd)

ptStart = ptEnd

if layercrs != epsg4326: # Convert each point to the output CRS

for x, pt in enumerate(pts):

pts[x] = transfrom4326.transform(pt)

ptset.append(pts)

if len(ptset) > 0:

featureout = QgsFeature()

featureout.setGeometry(QgsGeometry.fromPolygonXY(ptset))

featureout.setAttributes(feature.attributes())

sink.addFeature(featureout)

else:

multipoly = feature.geometry().asMultiPolygon()

multiset = []

for poly in multipoly:

ptset = []

for points in poly:

numpoints = len(points)

if numpoints < 2:

continue

# If the input is not 4326 we need to convert it to that and then back to the output CRS

ptStart = QgsPointXY(points[0][0], points[0][1])

if layercrs != epsg4326: # Convert to 4326

ptStart = transto4326.transform(ptStart)

pts = [ptStart]

for x in range(1, numpoints):

ptEnd = QgsPointXY(points[x][0], points[x][1])

if layercrs != epsg4326: # Convert to 4326

ptEnd = transto4326.transform(ptEnd)

gline = geod.InverseLine(ptStart.y(), ptStart.x(), ptEnd.y(), ptEnd.x())

if gline.s13 > maxseglen:

n = int(math.ceil(gline.s13 / maxseglen))

seglen = gline.s13 / n

for i in range(1, n):

s = seglen * i

g = gline.Position(s, Geodesic.LATITUDE | Geodesic.LONGITUDE | Geodesic.LONG_UNROLL)

pts.append(QgsPointXY(g['lon2'], g['lat2']))

pts.append(ptEnd)

ptStart = ptEnd

if layercrs != epsg4326: # Convert each point to the output CRS

for x, pt in enumerate(pts):

pts[x] = transfrom4326.transform(pt)

ptset.append(pts)

multiset.append(ptset)

if len(multiset) > 0:

featureout = QgsFeature()

featureout.setGeometry(QgsGeometry.fromMultiPolygonXY(multiset))

featureout.setAttributes(feature.attributes())

sink.addFeature(featureout)

except Exception:

num_bad += 1

'''s = traceback.format_exc()

feedback.pushInfo(s)'''

feedback.setProgress(int(cnt * total))

layercrs = source.sourceCrs()

if layercrs != epsg4326:

transto4326 = QgsCoordinateTransform(layercrs, epsg4326, QgsProject.instance())

transfrom4326 = QgsCoordinateTransform(epsg4326, layercrs, QgsProject.instance())

total = 100.0 / source.featureCount() if source.featureCount() else 0

iterator = source.getFeatures()

num_bad = 0

for cnt, feature in enumerate(iterator):

if feedback.isCanceled():

break

try:

if feature.geometry().isMultipart():

seg = feature.geometry().asMultiPolyline()

else:

seg = [feature.geometry().asPolyline()]

numseg = len(seg)

if numseg < 1 or len(seg[0]) < 2:

continue

# Create a new Line Feature

fline = QgsFeature()

# If the input is not 4326 we need to convert it to that and then back to the output CRS

if discardVertices:

ptStart = QgsPointXY(seg[0][0][0], seg[0][0][1])

if layercrs != epsg4326: # Convert to 4326

ptStart = transto4326.transform(ptStart)

pts = [ptStart]

numpoints = len(seg[numseg - 1])

ptEnd = QgsPointXY(seg[numseg - 1][numpoints - 1][0], seg[numseg - 1][numpoints - 1][1])

if layercrs != epsg4326: # Convert to 4326

ptEnd = transto4326.transform(ptEnd)

gline = geod.InverseLine(ptStart.y(), ptStart.x(), ptEnd.y(), ptEnd.x())

if gline.s13 > maxseglen:

n = int(math.ceil(gline.s13 / maxseglen))

seglen = gline.s13 / n

for i in range(1, n):

s = seglen * i

g = gline.Position(s, Geodesic.LATITUDE | Geodesic.LONGITUDE | Geodesic.LONG_UNROLL)

pts.append(QgsPointXY(g['lon2'], g['lat2']))

pts.append(ptEnd)

if layercrs != epsg4326: # Convert each point back to the output CRS

for x, pt in enumerate(pts):

pts[x] = transfrom4326.transform(pt)

fline.setGeometry(QgsGeometry.fromPolylineXY(pts))

else:

if not feature.geometry().isMultipart():

line = seg[0]

numpoints = len(line)

ptStart = QgsPointXY(line[0][0], line[0][1])

if layercrs != epsg4326: # Convert to 4326

ptStart = transto4326.transform(ptStart)

pts = [ptStart]

for x in range(1, numpoints):

ptEnd = QgsPointXY(line[x][0], line[x][1])

if layercrs != epsg4326: # Convert to 4326

ptEnd = transto4326.transform(ptEnd)

gline = geod.InverseLine(ptStart.y(), ptStart.x(), ptEnd.y(), ptEnd.x())

if gline.s13 > maxseglen:

n = int(math.ceil(gline.s13 / maxseglen))

seglen = gline.s13 / n

for i in range(1, n):

s = seglen * i

g = gline.Position(s, Geodesic.LATITUDE | Geodesic.LONGITUDE | Geodesic.LONG_UNROLL)

pts.append(QgsPointXY(g['lon2'], g['lat2']))

pts.append(ptEnd)

ptStart = ptEnd

if layercrs != epsg4326: # Convert each point back to the output CRS

for x, pt in enumerate(pts):

pts[x] = transfrom4326.transform(pt)

fline.setGeometry(QgsGeometry.fromPolylineXY(pts))

else: # MultiLineString

outseg = []

for line in seg:

numpoints = len(line)

ptStart = QgsPointXY(line[0][0], line[0][1])

if layercrs != epsg4326: # Convert to 4326

ptStart = transto4326.transform(ptStart)

pts = [ptStart]

for x in range(1, numpoints):

ptEnd = QgsPointXY(line[x][0], line[x][1])

if layercrs != epsg4326: # Convert to 4326

ptEnd = transto4326.transform(ptEnd)

gline = geod.InverseLine(ptStart.y(), ptStart.x(), ptEnd.y(), ptEnd.x())

if gline.s13 > maxseglen:

n = int(math.ceil(gline.s13 / maxseglen))

seglen = gline.s13 / n

for i in range(1, n):

s = seglen * i

g = gline.Position(s, Geodesic.LATITUDE | Geodesic.LONGITUDE | Geodesic.LONG_UNROLL)

pts.append(QgsPointXY(g['lon2'], g['lat2']))

pts.append(ptEnd)

ptStart = ptEnd

if layercrs != epsg4326: # Convert each point back to the output CRS

for x, pt in enumerate(pts):

pts[x] = transfrom4326.transform(pt)

outseg.append(pts)

fline.setGeometry(QgsGeometry.fromMultiPolylineXY(outseg))

fline.setAttributes(feature.attributes())

sink.addFeature(fline)

except Exception:

num_bad += 1

feedback.setProgress(int(cnt * total))