Nice_Hillshade_Model.py

"""
Model exported as python.
Name : Hillshade & Contours
Group : DEM Visualisation
With QGIS : 31803
"""

#REQUIRES THE TERRAIN SHADING PLUGIN

from qgis.core import QgsProcessing
from qgis.core import QgsProcessingAlgorithm
from qgis.core import QgsProcessingMultiStepFeedback
from qgis.core import QgsProcessingParameterRasterLayer
from qgis.core import QgsProcessingParameterNumber
from qgis.core import QgsProcessingParameterVectorDestination
from qgis.core import QgsProcessingParameterRasterDestination
import processing


class HillshadeContours(QgsProcessingAlgorithm):

    def initAlgorithm(self, config=None):
        self.addParameter(QgsProcessingParameterRasterLayer('DEM', 'DEM', defaultValue=None))
        self.addParameter(QgsProcessingParameterNumber('LateralExaggeration', 'Lateral Exaggeration', type=QgsProcessingParameterNumber.Double, minValue=0.1, defaultValue=5))
        self.addParameter(QgsProcessingParameterVectorDestination('Contours', 'Contours', type=QgsProcessing.TypeVectorLine, createByDefault=True, defaultValue=None))
        self.addParameter(QgsProcessingParameterRasterDestination('HillshadedDem', 'Hillshaded DEM', createByDefault=True, defaultValue=None))

    def processAlgorithm(self, parameters, context, model_feedback):
        # Use a multi-step feedback, so that individual child algorithm progress reports are adjusted for the
        # overall progress through the model
        feedback = QgsProcessingMultiStepFeedback(4, model_feedback)
        results = {}
        outputs = {}

        # 1st Gaussian Filter
        alg_params = {
            'INPUT': parameters['DEM'],
            'MODE': 1,
            'RADIUS': 3,
            'SIGMA': 2,
            'RESULT': QgsProcessing.TEMPORARY_OUTPUT
        }
        outputs['StGaussianFilter'] = processing.run('saga:gaussianfilter', alg_params, context=context, feedback=feedback, is_child_algorithm=True)

        feedback.setCurrentStep(1)
        if feedback.isCanceled():
            return {}

        # Contour Lines Extraction
        alg_params = {
            'BAND': 1,
            'CREATE_3D': False,
            'EXTRA': '',
            'FIELD_NAME': 'ELEV',
            'IGNORE_NODATA': False,
            'INPUT': outputs['StGaussianFilter']['RESULT'],
            'INTERVAL': 20,
            'NODATA': None,
            'OFFSET': 0,
            'OUTPUT': parameters['Contours']
        }
        outputs['ContourLinesExtraction'] = processing.run('gdal:contour', alg_params, context=context, feedback=feedback, is_child_algorithm=True)
        results['Contours'] = outputs['ContourLinesExtraction']['OUTPUT']

        feedback.setCurrentStep(2)
        if feedback.isCanceled():
            return {}

        # Terrain Shading Plugin Hillshade
        alg_params = {
            'ANGLE': 70,
            'BIDIRECTIONAL': True,
            'BYTE_FORMAT': False,
            'DENOISE': True,
            'DIRECTION': 315,
            'INPUT': outputs['StGaussianFilter']['RESULT'],
            'LAT_EX': parameters['LateralExaggeration'],
            'LONG_EX': 1,
            'OUTPUT': QgsProcessing.TEMPORARY_OUTPUT
        }
        outputs['TerrainShadingPluginHillshade'] = processing.run('terrain_shading:Hillshade (terrain shading)', alg_params, context=context, feedback=feedback, is_child_algorithm=True)

        feedback.setCurrentStep(3)
        if feedback.isCanceled():
            return {}

        # 2nd Gaussian Filter
        alg_params = {
            'INPUT': outputs['TerrainShadingPluginHillshade']['OUTPUT'],
            'MODE': 1,
            'RADIUS': 3,
            'SIGMA': 2,
            'RESULT': parameters['HillshadedDem']
        }
        outputs['NdGaussianFilter'] = processing.run('saga:gaussianfilter', alg_params, context=context, feedback=feedback, is_child_algorithm=True)
        results['HillshadedDem'] = outputs['NdGaussianFilter']['RESULT']
        return results

    def name(self):
        return 'Hillshade & Contours'

    def displayName(self):
        return 'Hillshade & Contours'

    def group(self):
        return 'DEM Visualisation'

    def groupId(self):
        return ''

    def createInstance(self):
        return HillshadeContours()