QGIS/python/plugins/processing/algs/gdal/Datasources2Vrt.py
2020-01-29 11:42:06 +10:00

131 lines
4.9 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
Datasources2Vrt.py
---------------------
Date : May 2015
Copyright : (C) 2015 by Luigi Pirelli
Email : luipir at gmail dot com
***************************************************************************
* *
* 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. *
* *
***************************************************************************
"""
__author__ = 'Luigi Pirelli'
__date__ = 'May 2015'
__copyright__ = '(C) 2015, Luigi Pirelli'
import html
from qgis.core import (QgsProcessing,
QgsProcessingException,
QgsProcessingParameterMultipleLayers,
QgsProcessingParameterBoolean,
QgsProcessingParameterVectorDestination,
QgsProcessingOutputString
)
from processing.algs.gdal.GdalAlgorithm import GdalAlgorithm
from processing.algs.gdal.GdalUtils import GdalUtils
class Datasources2Vrt(GdalAlgorithm):
INPUT = 'INPUT'
UNIONED = 'UNIONED'
OUTPUT = 'OUTPUT'
VRT_STRING = 'VRT_STRING'
def createCustomParametersWidget(self, parent):
return None
def group(self):
return self.tr('Vector miscellaneous')
def groupId(self):
return 'vectormiscellaneous'
def name(self):
return 'buildvirtualvector'
def displayName(self):
return self.tr('Build virtual vector')
def tags(self):
return ['ogr', 'gdal', 'vrt', 'create']
def shortHelpString(self):
return self.tr("This algorithm creates a virtual layer that contains a set of vector layers.\n\n"
"The output virtual layer will not be opened in the current project.")
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterMultipleLayers(self.INPUT,
self.tr('Input datasources'),
QgsProcessing.TypeVector))
self.addParameter(QgsProcessingParameterBoolean(self.UNIONED,
self.tr('Create "unioned" VRT'),
defaultValue=False))
class ParameterVectorVrtDestination(QgsProcessingParameterVectorDestination):
def __init__(self, name, description):
super().__init__(name, description)
def clone(self):
copy = ParameterVectorVrtDestination(self.name(), self.description())
return copy
def type(self):
return 'vrt_vector_destination'
def defaultFileExtension(self):
return 'vrt'
self.addParameter(ParameterVectorVrtDestination(self.OUTPUT,
self.tr('Virtual vector')))
self.addOutput(QgsProcessingOutputString(self.VRT_STRING,
self.tr('Virtual string')))
def processAlgorithm(self, parameters, context, feedback):
input_layers = self.parameterAsLayerList(parameters, self.INPUT, context)
unioned = self.parameterAsBoolean(parameters, self.UNIONED, context)
vrtPath = self.parameterAsOutputLayer(parameters, self.OUTPUT, context)
vrt = '<OGRVRTDataSource>'
if unioned:
vrt += '<OGRVRTUnionLayer name="UnionedLayer">'
total = 100.0 / len(input_layers) if input_layers else 0
for current, layer in enumerate(input_layers):
if feedback.isCanceled():
break
basePath = GdalUtils.ogrConnectionStringFromLayer(layer)
layerName = GdalUtils.ogrLayerName(layer.source())
vrt += '<OGRVRTLayer name="{}">'.format(html.escape(layerName, True))
vrt += '<SrcDataSource>{}</SrcDataSource>'.format(html.escape(basePath, True))
vrt += '<SrcLayer>{}</SrcLayer>'.format(html.escape(layerName, True))
vrt += '</OGRVRTLayer>'
feedback.setProgress(int(current * total))
if unioned:
vrt += '</OGRVRTUnionLayer>'
vrt += '</OGRVRTDataSource>'
with open(vrtPath, 'w', encoding='utf-8') as f:
f.write(vrt)
return {self.OUTPUT: vrtPath, self.VRT_STRING: vrt}
def commandName(self):
return ''