QGIS/python/plugins/processing/algs/qgis/ExtentFromLayer.py

142 lines
4.6 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
ExtentFromLayer.py
---------------------
Date : August 2012
Copyright : (C) 2012 by Victor Olaya
Email : volayaf 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__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os
from qgis.PyQt.QtGui import QIcon
from qgis.PyQt.QtCore import QVariant
from qgis.core import (QgsApplication,
QgsField,
QgsFeatureSink,
QgsGeometry,
QgsFeature,
QgsWkbTypes,
QgsProcessing,
QgsProcessingException,
QgsProcessingParameterMapLayer,
QgsProcessingParameterFeatureSink,
QgsFields)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class ExtentFromLayer(QgisAlgorithm):
INPUT = 'INPUT'
BY_FEATURE = 'BY_FEATURE'
OUTPUT = 'OUTPUT'
def icon(self):
return QgsApplication.getThemeIcon("/algorithms/mAlgorithmExtractLayerExtent.svg")
def svgIconPath(self):
return QgsApplication.iconPath("/algorithms/mAlgorithmExtractLayerExtent.svg")
def tags(self):
return self.tr('polygon,from,vector,raster,extent,envelope,bounds,bounding,boundary,layer').split(',')
def group(self):
return self.tr('Layer tools')
def groupId(self):
return 'layertools'
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterMapLayer(self.INPUT, self.tr('Input layer')))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Extent'), type=QgsProcessing.TypeVectorPolygon))
def name(self):
return 'polygonfromlayerextent'
def displayName(self):
return self.tr('Extract layer extent')
def processAlgorithm(self, parameters, context, feedback):
layer = self.parameterAsLayer(parameters, self.INPUT, context)
fields = QgsFields()
fields.append(QgsField('MINX', QVariant.Double))
fields.append(QgsField('MINY', QVariant.Double))
fields.append(QgsField('MAXX', QVariant.Double))
fields.append(QgsField('MAXY', QVariant.Double))
fields.append(QgsField('CNTX', QVariant.Double))
fields.append(QgsField('CNTY', QVariant.Double))
fields.append(QgsField('AREA', QVariant.Double))
fields.append(QgsField('PERIM', QVariant.Double))
fields.append(QgsField('HEIGHT', QVariant.Double))
fields.append(QgsField('WIDTH', QVariant.Double))
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.Polygon, layer.crs())
if sink is None:
raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))
try:
# may not be possible
layer.updateExtents()
except:
pass
rect = layer.extent()
geometry = QgsGeometry.fromRect(rect)
minx = rect.xMinimum()
miny = rect.yMinimum()
maxx = rect.xMaximum()
maxy = rect.yMaximum()
height = rect.height()
width = rect.width()
cntx = minx + width / 2.0
cnty = miny + height / 2.0
area = width * height
perim = 2 * width + 2 * height
feat = QgsFeature()
feat.setGeometry(geometry)
attrs = [
minx,
miny,
maxx,
maxy,
cntx,
cnty,
area,
perim,
height,
width,
]
feat.setAttributes(attrs)
sink.addFeature(feat, QgsFeatureSink.FastInsert)
return {self.OUTPUT: dest_id}