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As the title says, in QGIS 3.6 I made a model calculating "Forest fire susceptibility index - RC", model works fine and gives correct values. But when I export this model as Python script and run it the final result is false. Instead of giving values min: 32, max:110, it gives 1.79769e+308 and -1.79769e+308.

I need this Python script to work as model itself. Log doesn't report any error, it is a bit different though than log after running model. My guess is that something is wrong with line 132 with raster calculator. Here is the complete script:

from qgis.core import QgsProcessing
from qgis.core import QgsProcessingAlgorithm
from qgis.core import QgsProcessingMultiStepFeedback
from qgis.core import QgsProcessingParameterRasterLayer
from qgis.core import QgsProcessingParameterVectorLayer
from qgis.core import QgsProcessingParameterRasterDestination
import processing


class ForestFiresSusceptibilityIndexRc(QgsProcessingAlgorithm):

    def initAlgorithm(self, config=None):
        self.addParameter(QgsProcessingParameterRasterLayer('a', 'A', defaultValue=None))
        self.addParameter(QgsProcessingParameterVectorLayer('dr', 'Dr', types=[QgsProcessing.TypeVectorAnyGeometry], defaultValue=None))
        self.addParameter(QgsProcessingParameterVectorLayer('ds', 'Ds', types=[QgsProcessing.TypeVectorAnyGeometry], defaultValue=None))
        self.addParameter(QgsProcessingParameterRasterLayer('s', 'S', defaultValue=None))
        self.addParameter(QgsProcessingParameterVectorLayer('vt', 'Vt', types=[QgsProcessing.TypeVectorAnyGeometry], defaultValue=None))
        self.addParameter(QgsProcessingParameterRasterDestination('RcIndexSusceptibilityClasses', 'RC index - susceptibility classes', createByDefault=True, defaultValue=None))
        self.addParameter(QgsProcessingParameterRasterDestination('RcIndex', 'RC index', 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(7, model_feedback)
        results = {}
        outputs = {}

        # Reclassify by table - A
        alg_params = {
            'DATA_TYPE': 5,
            'INPUT_RASTER': parameters['a'],
            'NODATA_FOR_MISSING': False,
            'NO_DATA': -9999,
            'RANGE_BOUNDARIES': 1,
            'RASTER_BAND': 1,
            'TABLE': [0,0.00000001,2,0.00000001,22.5,1,22.5,67.5,2,67.5,112.5,3,112.5,157.5,4,157.5,202.5,5,202.5,247.5,4,247.5,292.5,3,292.5,337.5,2,337.5,400,1],
            'OUTPUT': QgsProcessing.TEMPORARY_OUTPUT
        }
        outputs['ReclassifyByTableA'] = processing.run('native:reclassifybytable', alg_params, context=context, feedback=feedback, is_child_algorithm=True)

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

        # Rasterize (vector to raster) - Dr
        alg_params = {
            'BURN': 0,
            'DATA_TYPE': 5,
            'EXTENT': parameters['dr'],
            'FIELD': 'Vrednost',
            'HEIGHT': 25,
            'INIT': None,
            'INPUT': parameters['dr'],
            'INVERT': False,
            'NODATA': -9999,
            'OPTIONS': '',
            'UNITS': 1,
            'WIDTH': 25,
            'OUTPUT': QgsProcessing.TEMPORARY_OUTPUT
        }
        outputs['RasterizeVectorToRasterDr'] = processing.run('gdal:rasterize', alg_params, context=context, feedback=feedback, is_child_algorithm=True)

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

        # Rasterize (vector to raster) - Ds
        alg_params = {
            'BURN': 0,
            'DATA_TYPE': 5,
            'EXTENT': parameters['ds'],
            'FIELD': 'Vrednost',
            'HEIGHT': 25,
            'INIT': None,
            'INPUT': parameters['ds'],
            'INVERT': False,
            'NODATA': -9999,
            'OPTIONS': '',
            'UNITS': 1,
            'WIDTH': 25,
            'OUTPUT': QgsProcessing.TEMPORARY_OUTPUT
        }
        outputs['RasterizeVectorToRasterDs'] = processing.run('gdal:rasterize', alg_params, context=context, feedback=feedback, is_child_algorithm=True)

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

        # Reclassify by table - S
        alg_params = {
            'DATA_TYPE': 5,
            'INPUT_RASTER': parameters['s'],
            'NODATA_FOR_MISSING': False,
            'NO_DATA': -9999,
            'RANGE_BOUNDARIES': 1,
            'RASTER_BAND': 1,
            'TABLE': [0,5,1,5,10,2,10,25,3,25,35,4,35,100,5],
            'OUTPUT': QgsProcessing.TEMPORARY_OUTPUT
        }
        outputs['ReclassifyByTableS'] = processing.run('native:reclassifybytable', alg_params, context=context, feedback=feedback, is_child_algorithm=True)

        feedback.setCurrentStep(4)
        if feedback.isCanceled():
            return {}

        # Rasterize (vector to raster) - Vt
        alg_params = {
            'BURN': 0,
            'DATA_TYPE': 5,
            'EXTENT': parameters['vt'],
            'FIELD': 'Vrednost',
            'HEIGHT': 25,
            'INIT': None,
            'INPUT': parameters['vt'],
            'INVERT': False,
            'NODATA': -9999,
            'OPTIONS': '',
            'UNITS': 1,
            'WIDTH': 25,
            'OUTPUT': QgsProcessing.TEMPORARY_OUTPUT
        }
        outputs['RasterizeVectorToRasterVt'] = processing.run('gdal:rasterize', alg_params, context=context, feedback=feedback, is_child_algorithm=True)

        feedback.setCurrentStep(5)
        if feedback.isCanceled():
            return {}

        # Raster calculator - RC index
        alg_params = {
            'CELLSIZE': 25,
            'CRS': 'ProjectCrs',
            'EXPRESSION': '7 * \"\'Rasterized\' from algorithm \'Rasterize (vector to raster) - Vt\'@1\" + 5 *  ( \"\'Reclassified raster\' from algorithm \'Reclassify by table - S\'@1\" + \"\'Reclassified raster\' from algorithm \'Reclassify by table - A\'@1\" )  + 3 *  ( \"\'Rasterized\' from algorithm \'Rasterize (vector to raster) - Dr\'@1\" + \"\'Rasterized\' from algorithm \'Rasterize (vector to raster) - Ds\'@1\" ) ',
            'EXTENT': outputs['RasterizeVectorToRasterVt']['OUTPUT'],
            'LAYERS': [outputs['RasterizeVectorToRasterDr']['OUTPUT'],outputs['RasterizeVectorToRasterDs']['OUTPUT'],outputs['RasterizeVectorToRasterVt']['OUTPUT'],outputs['ReclassifyByTableA']['OUTPUT'],outputs['ReclassifyByTableS']['OUTPUT']],
            'OUTPUT': parameters['RcIndex']
        }
        outputs['RasterCalculatorRcIndex'] = processing.run('qgis:rastercalculator', alg_params, context=context, feedback=feedback, is_child_algorithm=True)
        results['RcIndex'] = outputs['RasterCalculatorRcIndex']['OUTPUT']

        feedback.setCurrentStep(6)
        if feedback.isCanceled():
            return {}

        # Reclassify by table - RC index
        alg_params = {
            'DATA_TYPE': 5,
            'INPUT_RASTER': outputs['RasterCalculatorRcIndex']['OUTPUT'],
            'NODATA_FOR_MISSING': False,
            'NO_DATA': -9999,
            'RANGE_BOUNDARIES': 0,
            'RASTER_BAND': 1,
            'TABLE': [0,60,1,60,75,2,75,90,3,90,1000,4],
            'OUTPUT': parameters['RcIndexSusceptibilityClasses']
        }
        outputs['ReclassifyByTableRcIndex'] = processing.run('native:reclassifybytable', alg_params, context=context, feedback=feedback, is_child_algorithm=True)
        results['RcIndexSusceptibilityClasses'] = outputs['ReclassifyByTableRcIndex']['OUTPUT']
        return results

    def name(self):
        return 'Forest Fires Susceptibility Index - RC'

    def displayName(self):
        return 'Forest Fires Susceptibility Index - RC'

    def group(self):
        return 'GIS programiranje'

    def groupId(self):
        return 'GIS programiranje'

    def createInstance(self):
        return ForestFiresSusceptibilityIndexRc()
2
  • How are you running the stand alone script? May 27 '20 at 16:31
  • I am running it through QGIS 3.6.
    – Bane
    May 28 '20 at 17:14
1

The problem was/is definitely with raster calculator. So I overcame this problem by changing gdal's raster calculator with raster calculator provided by SAGA. The setup is a bit different, but overall it works. There is one strange issue though, sometimes code won't shoot results, but when I close and open QGIS and run it again immediately, it works. So this obviously needs some work, but if it can help someone I wanted to post this answer.

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