From 39b9c919bd5de6baba52ba9fbac6edd95afd6ae5 Mon Sep 17 00:00:00 2001
From: Qiusheng Wu <giswqs@gmail.com>
Date: Thu, 22 Aug 2024 16:11:52 -0400
Subject: [PATCH] Add support for DeckGL ArcLayer (#877)

---
 leafmap/common.py     | 40 ++++++++++++++++++
 leafmap/maplibregl.py | 97 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 137 insertions(+)

diff --git a/leafmap/common.py b/leafmap/common.py
index 0a466f96e8..d208dab582 100644
--- a/leafmap/common.py
+++ b/leafmap/common.py
@@ -14297,3 +14297,43 @@ def create_polyline(row):
     gdf = gdf.set_geometry("geometry")
     gdf.crs = crs
     return gdf
+
+
+def read_file(data: str, **kwargs: Any) -> Union[pd.DataFrame, "gpd.GeoDataFrame"]:
+    """
+    Reads a file and returns a DataFrame or GeoDataFrame.
+
+    Args:
+        data (str): The file path or a DataFrame/GeoDataFrame.
+        **kwargs (Any): Additional arguments passed to the file reading function.
+
+    Returns:
+        Union[pd.DataFrame, gpd.GeoDataFrame]: The read data as a DataFrame or GeoDataFrame.
+
+    Raises:
+        ValueError: If the data type is unsupported.
+    """
+    import geopandas as gpd
+
+    if isinstance(data, str):
+        if data.endswith(".parquet"):
+            df = pd.read_parquet(data, **kwargs)
+        elif data.endswith(".csv"):
+            df = pd.read_csv(data, **kwargs)
+        elif data.endswith(".json"):
+            df = pd.read_json(data, **kwargs)
+        elif data.endswith(".xlsx"):
+            df = pd.read_excel(data, **kwargs)
+        else:
+            df = gpd.read_file(data, **kwargs)
+    elif isinstance(data, dict) or isinstance(data, list):
+        df = pd.DataFrame(data, **kwargs)
+
+    elif isinstance(data, pd.DataFrame) or isinstance(data, gpd.GeoDataFrame):
+        df = data
+    else:
+        raise ValueError(
+            "Unsupported data type. Please provide a file path or a DataFrame."
+        )
+
+    return df
diff --git a/leafmap/maplibregl.py b/leafmap/maplibregl.py
index 12d978fdf4..b9938e854a 100644
--- a/leafmap/maplibregl.py
+++ b/leafmap/maplibregl.py
@@ -226,6 +226,103 @@ def remove_layer(self, name: str) -> None:
         if name in self.layer_dict:
             self.layer_dict.pop(name)
 
+    def add_deck_layers(self, layers: list[dict], tooltip: str | dict = None) -> None:
+        """Add Deck.GL layers to the layer stack
+
+        Args:
+            layers (list[dict]): A list of dictionaries containing the Deck.GL layers to be added.
+            tooltip (str | dict): Either a single mustache template string applied to all layers
+                or a dictionary where keys are layer ids and values are mustache template strings.
+        """
+        super().add_deck_layers(layers, tooltip)
+
+        for layer in layers:
+
+            self.layer_dict[layer["id"]] = {
+                "layer": layer,
+                "opacity": layer.get("opacity", 1.0),
+                "visible": layer.get("visible", True),
+                "type": layer.get("@@type", "deck"),
+                "color": layer.get("getFillColor", "#ffffff"),
+            }
+
+    def add_arc_layer(
+        self,
+        data: Union[str, pd.DataFrame],
+        src_lon: str,
+        src_lat: str,
+        dst_lon: str,
+        dst_lat: str,
+        src_color: List[int] = [255, 0, 0],
+        dst_color: List[int] = [255, 255, 0],
+        line_width: int = 2,
+        layer_id: str = "arc_layer",
+        pickable: bool = True,
+        tooltip: Optional[Union[str, List[str]]] = None,
+        **kwargs: Any,
+    ) -> None:
+        """
+        Add a DeckGL ArcLayer to the map.
+
+        Args:
+            data (Union[str, pd.DataFrame]): The file path or DataFrame containing the data.
+            src_lon (str): The source longitude column name.
+            src_lat (str): The source latitude column name.
+            dst_lon (str): The destination longitude column name.
+            dst_lat (str): The destination latitude column name.
+            src_color (List[int]): The source color as an RGB list.
+            dst_color (List[int]): The destination color as an RGB list.
+            line_width (int): The width of the lines.
+            layer_id (str): The ID of the layer.
+            pickable (bool): Whether the layer is pickable.
+            tooltip (Optional[Union[str, List[str]]], optional): The tooltip content or list of columns. Defaults to None.
+            **kwargs (Any): Additional arguments for the layer.
+
+        Returns:
+            None
+        """
+
+        df = read_file(data)
+        if "geometry" in df.columns:
+            df = df.drop(columns=["geometry"])
+
+        arc_data = [
+            {
+                "source_position": [row[src_lon], row[src_lat]],
+                "target_position": [row[dst_lon], row[dst_lat]],
+                **row.to_dict(),  # Include other columns
+            }
+            for _, row in df.iterrows()
+        ]
+
+        # Generate tooltip template dynamically based on the columns
+        if tooltip is None:
+            columns = df.columns
+        elif isinstance(tooltip, list):
+            columns = tooltip
+        tooltip_content = "<br>".join([f"{col}: {{{{ {col} }}}}" for col in columns])
+
+        deck_arc_layer = {
+            "@@type": "ArcLayer",
+            "id": layer_id,
+            "data": arc_data,
+            "getSourcePosition": "@@=source_position",
+            "getTargetPosition": "@@=target_position",
+            "getSourceColor": src_color,
+            "getTargetColor": dst_color,
+            "getWidth": line_width,
+            "pickable": pickable,
+        }
+
+        deck_arc_layer.update(kwargs)
+
+        self.add_deck_layers(
+            [deck_arc_layer],
+            tooltip={
+                layer_id: tooltip_content,
+            },
+        )
+
     def add_control(
         self, control: Union[str, Any], position: str = "top-right", **kwargs: Any
     ) -> None: