fix: standardised tiff shows white when using add alpha

scripts/gdal/gdal_preset.py

@@ -122,7 +122,7 @@ def get_gdal_command(preset: str, epsg: str) -> List[str]:
     return gdal_command
 
 
-def get_cutline_command(cutline: Optional[str]) -> List[str]:
+def get_alpha_command(cutline: Optional[str]) -> List[str]:
     """Get a `gdalwarp` command to create a virtual file (`.vrt`) which has a cutline applied and alpha added.
 
     Args:
@@ -148,33 +148,14 @@ def get_cutline_command(cutline: Optional[str]) -> List[str]:
     return gdal_command
 
 
-def get_build_vrt_command(files: List[str], output: str = "output.vrt", add_alpha: bool = False) -> List[str]:
-    gdal_command = ["gdalbuildvrt", "-hidenodata", "-strict"]
-    if add_alpha:
-        gdal_command.append("-addalpha")
+def get_build_vrt_command(files: List[str], output: str = "output.vrt") -> List[str]:
+    gdal_command = ["gdalbuildvrt", "-strict"]
     gdal_command.append(output)
     gdal_command += files
 
     return gdal_command
 
 
-def get_alpha_command() -> List[str]:
-    """Get a `gdalwarp` command to create a virtual file (.vrt) which has an alpha added.
-
-    Returns:
-        a list of arguments to run `gdalwarp`
-    """
-
-    return [
-        "gdalwarp",
-        # Outputting a VRT makes things faster as its not recomputing everything
-        "-of",
-        "VRT",
-        # Ensure the target has a alpha channel
-        "-dstalpha",
-    ]
-
-
 def get_transform_srs_command(source_epsg: str, target_epsg: str) -> List[str]:
     """Get a `gdalwarp` command to transform the srs.
 

scripts/gdal/tests/gdal_preset_test.py

@@ -1,4 +1,4 @@
-from scripts.gdal.gdal_preset import get_cutline_command, get_gdal_command
+from scripts.gdal.gdal_preset import get_alpha_command, get_gdal_command
 
 
 def test_preset_webp() -> None:
@@ -64,7 +64,7 @@ def test_preset_dem_lerc() -> None:
 
 
 def test_cutline_params() -> None:
-    gdal_command = get_cutline_command("cutline.fgb")
+    gdal_command = get_alpha_command("cutline.fgb")
 
     assert "-cutline" in gdal_command
     assert "cutline.fgb" in gdal_command

scripts/standardising.py

@@ -13,7 +13,7 @@
 from scripts.files.fs import exists, read, write
 from scripts.gdal.gdal_bands import get_gdal_band_offset
 from scripts.gdal.gdal_helper import get_gdal_version, run_gdal
-from scripts.gdal.gdal_preset import get_build_vrt_command, get_cutline_command, get_gdal_command, get_transform_srs_command
+from scripts.gdal.gdal_preset import get_alpha_command, get_build_vrt_command, get_gdal_command, get_transform_srs_command
 from scripts.gdal.gdalinfo import gdal_info
 from scripts.logging.time_helper import time_in_ms
 from scripts.tile.tile_index import Bounds, get_bounds_from_name
@@ -107,10 +107,10 @@ def download_tiffs(files: List[str], target: str) -> List[str]:
     return downloaded_files
 
 
-def create_vrt(source_tiffs: List[str], target_path: str, add_alpha: bool = False) -> str:
+def create_vrt(source_tiffs: List[str], target_path: str) -> str:
     # Create the `vrt` file
     vrt_path = os.path.join(target_path, "source.vrt")
-    run_gdal(command=get_build_vrt_command(files=source_tiffs, output=vrt_path, add_alpha=add_alpha))
+    run_gdal(command=get_build_vrt_command(files=source_tiffs, output=vrt_path))
     return vrt_path
 
 
@@ -166,7 +166,9 @@ def standardising(
                 vrt_add_alpha = False
 
         # Start from base VRT
-        input_file = create_vrt(source_tiffs, tmp_path, add_alpha=vrt_add_alpha)
+        input_file = create_vrt(source_tiffs, tmp_path)
+        target_vrt = "target.vrt"
+        input_cutline_path = ""
 
         # Apply cutline
         if cutline:
@@ -178,9 +180,9 @@ def standardising(
                 # Ensure the input cutline is a easy spot for GDAL to read
                 write(input_cutline_path, read(cutline))
 
-            target_vrt = os.path.join(tmp_path, "cutline.vrt")
-            # TODO: test a cutline with a VRT file
-            run_gdal(get_cutline_command(input_cutline_path), input_file=input_file, output_file=target_vrt)
+        # TODO: test a cutline with a VRT file
+        if cutline or vrt_add_alpha:
+            run_gdal(get_alpha_command(input_cutline_path), input_file=input_file, output_file=target_vrt)
             input_file = target_vrt
 
         # Reproject tiff if needed