Merge pull request #365 from kartoza/osundwajeff/issue348

Convert raster to 8bit function and test

geest/core/convert_to_8bit.py

@@ -0,0 +1,57 @@
+import os
+import processing
+from qgis.core import QgsMessageLog, Qgis, QgsRasterLayer, QgsProject
+
+
+class RasterConverter:
+ """
+ A class to handle the conversion of rasters to 8-bit TIFFs.
+ """
+
+ def __init__(self, feedback=None):
+ """
+ Initialize the RasterConverter with optional feedback for progress reporting.
+ :param feedback: Optional QgsFeedback object for reporting progress.
+ """
+ self.feedback = feedback
+
+ def convert_to_8bit(self, input_raster: str, output_raster: str) -> bool:
+ """
+ Convert the input raster to an 8-bit TIFF using gdal:translate.
+ :param input_raster: Path to the input raster file.
+ :param output_raster: Path to the output 8-bit TIFF file.
+ :return: True if conversion is successful, False otherwise.
+ """
+ QgsMessageLog.logMessage(
+ f"Converting {input_raster} to 8-bit TIFF at {output_raster}.",
+ tag="RasterConverter",
+ level=Qgis.Info,
+ )
+
+ params = {
+ "INPUT": input_raster,
+ "TARGET_CRS": None, # Use input CRS
+ "NODATA": -9999,
+ "COPY_SUBDATASETS": False,
+ "OPTIONS": "",
+ "EXTRA": "",
+ "DATA_TYPE": 1, # 1 = Byte (8-bit unsigned)
+ "OUTPUT": output_raster,
+ }
+
+ try:
+ # Run the gdal:translate processing algorithm
+ processing.run("gdal:translate", params, feedback=self.feedback)
+ QgsMessageLog.logMessage(
+ f"Successfully converted {input_raster} to 8-bit TIFF.",
+ tag="RasterConverter",
+ level=Qgis.Info,
+ )
+ return True
+ except Exception as e:
+ QgsMessageLog.logMessage(
+ f"Failed to convert {input_raster} to 8-bit: {str(e)}",
+ tag="RasterConverter",
+ level=Qgis.Critical,
+ )
+ return False

geest/core/workflows/factor_aggregation_workflow.py

@@ -9,6 +9,7 @@
 )
 from qgis.analysis import QgsRasterCalculator, QgsRasterCalculatorEntry
 from .workflow_base import WorkflowBase
+from geest.core.convert_to_8bit import RasterConverter
 
 
 class FactorAggregationWorkflow(WorkflowBase):
@@ -113,6 +114,16 @@ def aggregate_vrt_files(self, vrt_files: list) -> None:
  # Run the calculation
  result = calc.processCalculation()
 
+ converter = RasterConverter()
+
+ aggregation_output_8bit = aggregation_output.replace(".tif", "_8bit.tif")
+
+ # Convert the aggregated raster to 8-bit
+ converter.convert_to_8bit(aggregation_output, aggregation_output_8bit)
+
+ if os.path.exists(aggregation_output_8bit):
+ os.remove(aggregation_output)
+
  if result == 0:
  QgsMessageLog.logMessage(
  "Raster aggregation completed successfully.",
@@ -121,7 +132,7 @@ def aggregate_vrt_files(self, vrt_files: list) -> None:
  )
  # Add the aggregated raster to the map
  aggregated_layer = QgsRasterLayer(
- aggregation_output, f"{self.indicator_name}"
+ aggregation_output_8bit, f"{self.indicator_name}"
  )
  if aggregated_layer.isValid():
  # Copy the style (.qml) file to the same directory as the VRT
@@ -134,7 +145,9 @@ def aggregate_vrt_files(self, vrt_files: list) -> None:
  qml_dest_path = os.path.join(
  self.workflow_directory,
  "contextual",
- os.path.basename(aggregation_output).replace(".tif", ".qml"),
+ os.path.basename(aggregation_output_8bit).replace(
+ ".tif", ".qml"
+ ),
  )
  shutil.copy(qml_src_path, qml_dest_path)
  QgsMessageLog.logMessage(

test/test_convert_to_8bit.py

@@ -0,0 +1,61 @@
+import os
+import unittest
+from qgis.core import QgsApplication, QgsRasterLayer, Qgis
+from geest.core.convert_to_8bit import RasterConverter
+
+
+class TestRasterConverter(unittest.TestCase):
+
+ @classmethod
+ def setUpClass(self):
+
+ # Define paths to input and output files
+ self.input_raster = os.path.join(
+ os.path.dirname(__file__), "test_data/rasters/raster.tif"
+ )
+ self.output_raster = os.path.join(
+ os.path.dirname(__file__), "output/output_raster_8bit.tif"
+ )
+
+ def test_convert_to_8bit(self):
+ """
+ Test the convert_to_8bit method of the RasterConverter class.
+ """
+ # Create an instance of RasterConverter
+ converter = RasterConverter()
+
+ # Ensure input file exists before running the test
+ self.assertTrue(
+ os.path.exists(self.input_raster), "Input raster file does not exist"
+ )
+
+ # Check if the input image is 32-bit using QGIS API
+ input_layer = QgsRasterLayer(self.input_raster, "Test Raster")
+ self.assertTrue(input_layer.isValid(), "Raster layer is not valid")
+
+ # Get the raster band data type
+ input_provider = input_layer.dataProvider()
+ input_band_data_type = input_provider.dataType(1)
+
+ self.assertEqual(input_band_data_type, Qgis.Float32, "Input raster is 32-bit")
+
+ # Run the conversion
+ success = converter.convert_to_8bit(self.input_raster, self.output_raster)
+
+ # Check if the conversion was successful
+ self.assertTrue(success, "Raster conversion failed")
+
+ # Check if the output image is 8-bit using QGIS API
+ raster_layer = QgsRasterLayer(self.output_raster, "Test Raster")
+ self.assertTrue(raster_layer.isValid(), "Raster layer is not valid")
+
+ # Get the raster band data type
+ provider = raster_layer.dataProvider()
+ band_data_type = provider.dataType(1)
+
+ # Assert if the raster data type is 8-bit
+ self.assertEqual(band_data_type, Qgis.Byte, "Output raster is not 8-bit")
+
+
+if __name__ == "__main__":
+ unittest.main()