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"""
***************************************************************************
v_net.py
--------
Date : December 2015
Copyright : (C) 2015 by Médéric Ribreux
Email : medspx at medspx dot fr
***************************************************************************
* *
* 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. *
* *
***************************************************************************
This Python module handles pre-treatment operations for v.net.* GRASS modules.
Before using a v.net module you often have to incorporate a points layer into
the network vector map.
"""
__author__ = "Médéric Ribreux"
__date__ = "December 2015"
__copyright__ = "(C) 2015, Médéric Ribreux"
import os
from qgis.core import QgsProcessingException
from processing.tools.system import getTempFilename
from qgis.PyQt.QtCore import QCoreApplication
def incorporatePoints(
alg,
parameters,
context,
feedback,
pointLayerName="points",
networkLayerName="input",
):
"""
incorporate points with lines to form a GRASS network
"""
# Grab the point layer and delete this parameter
pointLayer = alg.parameterAsVectorLayer(parameters, pointLayerName, context)
if pointLayer:
# Create an intermediate GRASS layer which is the combination of network + centers
intLayer = "net" + os.path.basename(getTempFilename(context=context))
pointLayer = alg.exportedLayers[pointLayerName]
# Grab the network layer
lineLayer = alg.parameterAsVectorLayer(parameters, networkLayerName, context)
if lineLayer:
lineLayer = alg.exportedLayers[networkLayerName]
else:
raise QgsProcessingException(
QCoreApplication.translate(
"GrassAlgorithmExt", "GRASS GIS v.net requires a lines layer!"
)
)
threshold = alg.parameterAsDouble(parameters, "threshold", context)
# Create the v.net connect command for point layer integration
command = "v.net -s input={} points={} output={} operation=connect threshold={}".format(
lineLayer, pointLayer, intLayer, threshold
)
alg.commands.append(command)
# Connect the point layer database to the layer 2 of the network
command = f"v.db.connect -o map={intLayer} table={pointLayer} layer=2"
alg.commands.append(command)
# remove undesired parameters
alg.removeParameter(pointLayerName)
# Use temp layer for input
alg.exportedLayers[networkLayerName] = intLayer
# Process the command
if "threshold" in parameters:
alg.removeParameter("threshold")
alg.processCommand(parameters, context, feedback)
def variableOutput(alg, layers, parameters, context, nocats=True):
"""Handle variable data output for v.net modules:
:param layers:
layers is a dict of outputs:
{ 'outputName': ['srcLayer', 'output_type', output_layer_number, nocats],
...
}
where:
- outputName is the name of the output in the description file.
- srcLayer is the grass name of the layer to export.
- output_type is the GRASS datatype (point/line/area/etc.).
- output_layer_number is the GRASS layer number for multiple layers datasets.
- nocats indicates weither we need to also export without categories items.
:param parameters:
:param context:
:param nocats: do not add categories.
"""
for outputName, typeList in layers.items():
if not isinstance(typeList, list):
continue
file_name = alg.parameterAsOutputLayer(parameters, outputName, context)
src_layer = typeList[0]
output_type = typeList[1]
output_layer_number = typeList[2]
no_cats = typeList[3]
grass_name = f"{src_layer}{alg.uniqueSuffix}"
alg.exportVectorLayer(
grassName=grass_name,
fileName=file_name,
layer=output_layer_number,
exportnocat=no_cats,
dataType=output_type,
)
def processOutputs(alg, parameters, context, feedback):
idx = alg.parameterAsInt(parameters, "operation", context)
operations = alg.parameterDefinition("operation").options()
operation = operations[idx]
if operation == "nodes":
outputParameter = {"output": ["output", "point", 2, True]}
elif operation == "connect":
outputParameter = {"output": ["output", "line", 1, False]}
elif operation == "arcs":
outputParameter = {"output": ["output", "line", 1, True]}
variableOutput(alg, outputParameter, parameters, context)
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