Merge pull request #134 from Open-EO/133-compression-uint8

Added rescaling method

src/openeo_gfmap/preprocessing/scaling.py

@@ -3,6 +3,21 @@
 import openeo
 
 
+def _compress(
+    cube: openeo.DataCube,
+    min_val: int,
+    max_val: int,
+    alpha: float,
+    beta: float,
+):
+    if (
+        alpha != 1.0 or beta != 0.0
+    ):  # Avoid adding a node in the computing graph if scaling is not necessary
+        cube = (cube * alpha) + beta
+
+    return cube.linear_scale_range(min_val, max_val, min_val, max_val)
+
+
 def compress_uint16(
     cube: openeo.DataCube, alpha: float = 1.0, beta: float = 0.0
 ) -> openeo.DataCube:
@@ -23,9 +38,28 @@ def compress_uint16(
     cube : openeo.DataCube
         The datacube with the data linearly scaled and compressed to uint16 and rescaled frome.
     """
-    if (
-        alpha != 1.0 or beta != 0.0
-    ):  # Avoid adding a node in the computing graph if scaling is not necessary
-        cube = (cube * alpha) + beta
+    return _compress(cube, 0, 65534, alpha, beta)
+
 
-    return cube.linear_scale_range(0, 65534, 0, 65534)
+def compress_uint8(
+    cube: openeo.DataCube, alpha: float = 1.0, beta: float = 0.0
+) -> openeo.DataCube:
+    """
+    Scales the data linearly using the formula `output = (input * a) + b` and compresses values
+    from float32 to uint8 for memory optimization.
+
+    Parameters
+    ----------
+    cube : openeo.DataCube
+        The input datacube to compress, only meteo data should be present.
+    alpha : float, optional (default=1.0)
+        The scaling factor. Values in the input datacube are multiplied by this coefficient.
+    beta : float, optional (default=0.0)
+        The offset. Values in the input datacube are added by this value.
+
+    Returns
+    -------
+    cube : openeo.DataCube
+        The datacube with the data linearly scaled and compressed to uint8 and rescaled frome.
+    """
+    return _compress(cube, 0, 253, alpha, beta)