resolved #988

enmapboxprocessing/algorithm/createspectralindicesalgorithm.py

@@ -1,24 +1,26 @@
+import re
 from collections import OrderedDict
+from copy import deepcopy
 from typing import Dict, Any, List, Tuple, Optional
-import re
 
 from osgeo import gdal
 
+from enmapbox.typeguard import typechecked
 from enmapboxprocessing.algorithm.vrtbandmathalgorithm import VrtBandMathAlgorithm
 from enmapboxprocessing.enmapalgorithm import EnMAPProcessingAlgorithm, Group
 from enmapboxprocessing.gdalutils import GdalUtils
 from enmapboxprocessing.rasterreader import RasterReader
 from enmapboxprocessing.rasterwriter import RasterWriter
 from enmapboxprocessing.utils import Utils
 from qgis.core import (QgsProcessingContext, QgsProcessingFeedback, QgsProcessingException,
-                       QgsRasterLayer)
-from enmapbox.typeguard import typechecked
+                       QgsRasterLayer, QgsProcessingParameterFile)
 
 
 @typechecked
 class CreateSpectralIndicesAlgorithm(EnMAPProcessingAlgorithm):
     P_RASTER, _RASTER = 'raster', 'Raster layer'
     P_INDICES, _INDICES = 'indices', 'Indices'
+    P_JSON_FILE, _JSON_FILE = 'formulars', 'Formulars'
     P_SCALE, _SCALE = 'scale', 'Scale factor'
 
     P_A, _A = 'A', 'Aerosols band'
@@ -87,13 +89,19 @@ def shortDescription(self) -> str:
                f'Should you need other indices added after this date, please file an issue.'
 
     def helpParameters(self) -> List[Tuple[str, str]]:
+        link = self.htmlLink(
+            'https://raw.githubusercontent.com/EnMAP-Box/enmap-box/refs/heads/main/enmapboxprocessing/algorithm/createspectralindicesalgorithm.other.json',
+            'createspectralindicesalgorithm.other.json'
+        )
         helpParameters = [
             (self._RASTER, 'A spectral raster layer.'),
             (self._INDICES, 'The list of indices to be created. Usage examples:\n'
                             'Create (predefined) NDVI: <code>NDVI</code>\n'
                             'Create stack of NDVI and EVI: <code>NDVI, EVI</code>\n'
                             'Create custom index: <code>MyNDVI = (N - R) / (N + R)</code>\n'
                             f'See the full list of predefined  {self.linkAwesomeSpectralIndices}.'),
+            (self._JSON_FILE, 'A JSON file with additional spectral index formulars to be used.\n'
+                              f'See {link} for the expected format.'),
             (self._SCALE, 'Spectral reflectance scale factor. '
                           'Some indices require data to be scaled into the 0 to 1 range. '
                           'If your data is scaled differently, specify an appropriate scale factor.'
@@ -118,6 +126,10 @@ def initAlgorithm(self, configuration: Dict[str, Any] = None):
         self.addParameterRasterLayer(self.P_RASTER, self._RASTER)
         self.addParameterString(self.P_INDICES, self._INDICES, 'NDVI', True)
         self.addParameterFloat(self.P_SCALE, self._SCALE, None, True)
+        self.addParameterFile(
+            self.P_JSON_FILE, self._JSON_FILE, QgsProcessingParameterFile.Behavior.File, self.JsonFileExtension,
+            None, True
+        )
         for name in self.WavebandMapping:
             description = getattr(self, '_' + name)
             self.addParameterBand(name, description, -1, self.P_RASTER, True, False, True)
@@ -130,6 +142,7 @@ def processAlgorithm(
             self, parameters: Dict[str, Any], context: QgsProcessingContext, feedback: QgsProcessingFeedback
     ) -> Dict[str, Any]:
         raster = self.parameterAsRasterLayer(parameters, self.P_RASTER, context)
+        jsonFile = self.parameterAsFile(parameters, self.P_JSON_FILE, context)
         text = self.parameterAsString(parameters, self.P_INDICES, context)
         text = ', '.join(text.splitlines())  # multiline to comma separated list
         scale = self.parameterAsFloat(parameters, self.P_SCALE, context)
@@ -151,13 +164,20 @@ def processAlgorithm(
                     bandNo = self.findBroadBand(raster, name, True)
                 bandNos[name] = bandNo
 
+            # add user-defined formulars
+            IndexDatabase = deepcopy(self.IndexDatabase)
+            if jsonFile is not None:
+                IndexDatabase.update(  # more indices
+                    Utils.jsonLoad(jsonFile)['SpectralIndices']
+                )
+
             # eval requested indices
             indices = OrderedDict()
             for item in text.split(','):
 
                 if '=' in item:  # custom index
                     short_name, formula = [s.strip() for s in item.split('=')]
-                    if short_name in self.IndexDatabase:
+                    if short_name in IndexDatabase:
                         raise QgsProcessingException(
                             f'custom index name already exists as a predefined index: {short_name}'
                         )
@@ -172,12 +192,12 @@ def processAlgorithm(
                     bandName = short_name
                 else:  # predefined index
                     short_name = item.strip()
-                    if short_name not in self.IndexDatabase:
+                    if short_name not in IndexDatabase:
                         raise QgsProcessingException(f'unknown index: {short_name}')
-                    formula = self.IndexDatabase[short_name]['formula']
-                    bands = self.IndexDatabase[short_name]['bands']
+                    formula = IndexDatabase[short_name]['formula']
+                    bands = IndexDatabase[short_name]['bands']
                     bands = [name for name in bands if name not in self.ConstantMapping]  # skip constants
-                    long_name = self.IndexDatabase[short_name]['long_name']
+                    long_name = IndexDatabase[short_name]['long_name']
                     bandName = short_name + ' - ' + long_name
 
                 bandList = [bandNos[name] for name in bands]

tests/enmap-box/enmapboxprocessing/algorithm/test_CreateSpectralIndicesAlgorithm.py

@@ -6,6 +6,7 @@
 from enmapboxprocessing.algorithm.createspectralindicesalgorithm import CreateSpectralIndicesAlgorithm
 from enmapboxprocessing.algorithm.testcase import TestCase
 from enmapboxprocessing.rasterreader import RasterReader
+from enmapboxprocessing.utils import Utils
 from enmapboxtestdata import enmap
 from qgis.core import QgsProcessingException
 
@@ -108,3 +109,34 @@ def test_saveAsTif(self):
         ds: gdal.Dataset = gdal.Open(result[alg.P_OUTPUT_RASTER])
         driver: gdal.Driver = ds.GetDriver()
         self.assertEqual('GeoTIFF', driver.LongName)
+
+    def test_indicesFromFile(self):
+
+        formulars = {
+            "SpectralIndices": {
+                "MY_INDEX": {
+                    "bands": [
+                        "N",
+                        "S1",
+                        "S2"
+                    ],
+                    "formula": "(N - S1) / (N + S1)",
+                    "long_name": "Normalized Difference Moisture Index",
+                    "reference": "https://doi.org/10.1016/S0034-4257(96)00067-3",
+                    "short_name": "MY_INDEX",
+                    "type": "other"
+                }
+            }
+        }
+
+        Utils().jsonDump(formulars, self.filename('formulars.json'))
+
+        alg = CreateSpectralIndicesAlgorithm()
+        alg.initAlgorithm()
+        parameters = {
+            alg.P_RASTER: enmap,
+            alg.P_INDICES: 'MY_INDEX',
+            alg.P_JSON_FILE: self.filename('formulars.json'),
+            alg.P_OUTPUT_RASTER: self.filename('index.vrt'),
+        }
+        self.runalg(alg, parameters)