def processAlgorithm(self, parameters, context, feedback): source = self.parameterAsSource(parameters, self.INPUT, context) if source is None: raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT)) extent = self.parameterAsExtent(parameters, self.TARGET_AREA, context) target_crs = self.parameterAsExtentCrs(parameters, self.TARGET_AREA, context) if self.TARGET_AREA_CRS in parameters: c = self.parameterAsCrs(parameters, self.TARGET_AREA_CRS, context) if c.isValid(): target_crs = c target_geom = QgsGeometry.fromRect(extent) fields = QgsFields() fields.append(QgsField('auth_id', QVariant.String, '', 20)) (sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context, fields, QgsWkbTypes.NoGeometry, QgsCoordinateReferenceSystem()) if sink is None: raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT)) # make intersection tests nice and fast engine = QgsGeometry.createGeometryEngine(target_geom.constGet()) engine.prepareGeometry() layer_bounds = QgsGeometry.fromRect(source.sourceExtent()) crses_to_check = QgsCoordinateReferenceSystem.validSrsIds() total = 100.0 / len(crses_to_check) found_results = 0 transform_context = QgsCoordinateTransformContext() for current, srs_id in enumerate(crses_to_check): if feedback.isCanceled(): break candidate_crs = QgsCoordinateReferenceSystem.fromSrsId(srs_id) if not candidate_crs.isValid(): continue transform_candidate = QgsCoordinateTransform(candidate_crs, target_crs, transform_context) transform_candidate.setBallparkTransformsAreAppropriate(True) transform_candidate.disableFallbackOperationHandler(True) transformed_bounds = QgsGeometry(layer_bounds) try: if transformed_bounds.transform(transform_candidate) != 0: continue except: continue try: if engine.intersects(transformed_bounds.constGet()): feedback.pushInfo(self.tr('Found candidate CRS: {}').format(candidate_crs.authid())) f = QgsFeature(fields) f.setAttributes([candidate_crs.authid()]) sink.addFeature(f, QgsFeatureSink.FastInsert) found_results += 1 except: continue feedback.setProgress(int(current * total)) if found_results == 0: feedback.reportError(self.tr('No matching projections found')) return {self.OUTPUT: dest_id}