add sum algorithm (#1212)

Author: vincentsarago

CHANGES.md

@@ -2,6 +2,12 @@
 
 ## Unreleased
 
+## 0.23.1 (2025-08-27)
+
+### titiler.core
+
+* add `sum` algorithm
+
 ## 0.23.0 (2025-08-26)
 
 ### titiler.core

docs/src/user_guide/algorithms.md

@@ -22,6 +22,7 @@ We added a set of custom algorithms:
 - `mean`: Return **Mean** values along the `bands` axis.
 - `std`: Return the **Standard Deviation** along the `bands` axis.
 - `var`: Return **Variance** along the `bands` axis.
+- `sum`: Return **Sum** along the `bands` axis.
 
 
 ### Usage

src/titiler/core/tests/test_algorithms.py

@@ -328,6 +328,7 @@ def test_ops():
         ("mean", numpy.ma.mean, {}),
         ("std", numpy.ma.std, {"ddof": 1}),
         ("var", numpy.ma.var, {"ddof": 1}),
+        ("sum", numpy.ma.sum, {}),
     ],
 )
 def test_math_algorithm(name, numpy_method, options):

src/titiler/core/titiler/core/algorithm/__init__.py

@@ -13,7 +13,7 @@
 from titiler.core.algorithm.base import BaseAlgorithm
 from titiler.core.algorithm.dem import Contours, HillShade, Slope, TerrainRGB, Terrarium
 from titiler.core.algorithm.index import NormalizedIndex
-from titiler.core.algorithm.math import _Max, _Mean, _Median, _Min, _Std, _Var
+from titiler.core.algorithm.math import _Max, _Mean, _Median, _Min, _Std, _Sum, _Var
 from titiler.core.algorithm.ops import CastToInt, Ceil, Floor
 
 default_algorithms: Dict[str, Type[BaseAlgorithm]] = {
@@ -32,6 +32,7 @@
     "mean": _Mean,
     "std": _Std,
     "var": _Var,
+    "sum": _Sum,
 }
 
 

src/titiler/core/titiler/core/algorithm/math.py

@@ -5,7 +5,7 @@
 
 from titiler.core.algorithm.base import BaseAlgorithm
 
-__all__ = ["_Min", "_Max", "_Median", "_Mean", "_Std", "_Var"]
+__all__ = ["_Min", "_Max", "_Median", "_Mean", "_Std", "_Var", "_Sum"]
 
 
 class _Min(BaseAlgorithm):
@@ -136,3 +136,24 @@ def __call__(self, img: ImageData) -> ImageData:
             metadata=img.metadata,
             cutline_mask=img.cutline_mask,
         )
+
+
+class _Sum(BaseAlgorithm):
+    """Return Sum values along the `bands` axis."""
+
+    title: str = "Sum"
+    description: str = "Return Sum values along the `bands` axis."
+
+    output_nbands: int = 1
+
+    def __call__(self, img: ImageData) -> ImageData:
+        """Return Min."""
+        return ImageData(
+            numpy.ma.sum(img.array, axis=0, keepdims=True),
+            assets=img.assets,
+            crs=img.crs,
+            bounds=img.bounds,
+            band_names=["sum"],
+            metadata=img.metadata,
+            cutline_mask=img.cutline_mask,
+        )