high-level viz api (#32)

lonboard/__init__.py

@@ -1,2 +1,3 @@
 from .layer import LineStringLayer, PointLayer, PolygonLayer
+from .viz import viz
 from .widget import Map

lonboard/viz.py

@@ -0,0 +1,30 @@
+"""High-level, super-simple API for visualizing GeoDataFrames
+"""
+
+# TODO: avoid geopandas hard dependency
+import geopandas as gpd
+
+from lonboard.geoarrow.geopandas_interop import geopandas_to_geoarrow
+from lonboard.layer import LineStringLayer, PointLayer, PolygonLayer
+from lonboard.widget import Map
+
+
+def viz(data: gpd.GeoDataFrame, **kwargs) -> Map:
+    table = geopandas_to_geoarrow(data)
+    geometry_ext_type = table.schema.field("geometry").metadata.get(
+        b"ARROW:extension:name"
+    )
+
+    if geometry_ext_type == "geoarrow.point":
+        layer = PointLayer.from_pyarrow(table, **kwargs)
+        return Map(layers=[layer])
+    elif geometry_ext_type == "geoarrow.linestring":
+        layer = LineStringLayer.from_pyarrow(table, **kwargs)
+        return Map(layers=[layer])
+    elif geometry_ext_type == "geoarrow.point":
+        layer = PolygonLayer.from_pyarrow(table, **kwargs)
+        return Map(layers=[layer])
+
+    raise ValueError(
+        "Only point, linestring, and polygon geometry types currently supported."
+    )