restrict to one polygon

app.py

@@ -5,6 +5,22 @@ import pandas as pd
 import geopandas as gpd
 import leafmap.foliumap as leafmap
 from optree import tree_map
+from shapely.ops import transform
+
+
+def shape_3d_to_2d(shape):
+    if shape.has_z:
+        return transform(lambda x, y, z: (x, y), shape)
+    else:
+        return shape
+
+
+def preprocess_gdf(gdf):
+    gdf = gdf.to_crs(epsg=7761)  # epsg for Gujarat
+    gdf["geometry"] = gdf["geometry"].apply(shape_3d_to_2d)
+    gdf["geometry"] = gdf.buffer(0)  # Fixes some invalid geometries
+    return gdf
+
 
 # wide streamlit display
 st.set_page_config(layout="wide")
@@ -40,7 +56,7 @@ if not file_url:
 if not file_url:
     st.stop()
 
-if ("file_url" in st.session_state) and (st.session_state.file_url == file_url):
+if ("file_url" in st.session_state) and ("input_gdf" in st.session_state) and (st.session_state.file_url == file_url):
     # st.toast("Using cached data")
     input_gdf = st.session_state.input_gdf
 else:
@@ -53,8 +69,12 @@ else:
             ID = file_url.replace("https://drive.google.com/open?id=", "")
             file_url = f"https://drive.google.com/uc?id={ID}"
 
-    input_gdf = gpd.read_file(file_url)
-    input_gdf = input_gdf.to_crs(epsg=7761)  # Gujarat zone
+    input_gdf = preprocess_gdf(gpd.read_file(file_url))
+    if len(input_gdf) != 1:
+        st.error(
+            f"Expecting only one geometry per KML, but found {len(input_gdf)} geometries. Please fix the KML or provide another KML."
+        )
+        st.stop()
     st.session_state.input_gdf = input_gdf
     # st.toast("Data loaded and cached")
 
@@ -64,7 +84,7 @@ def format_fn(x):
 
 
 with st.expander("Advanced Controls", expanded=False):
-    input_geometry_idx = st.selectbox("Select the geometry", input_gdf.index, format_func=format_fn)
+    # input_geometry_idx = st.selectbox("Select the geometry", input_gdf.index, format_func=format_fn)
     map_type = st.radio(
         "",
         ["Esri Satellite Map", "Google Hybrid Map (displays place names)", "Google Satellite Map"],
@@ -72,7 +92,7 @@ with st.expander("Advanced Controls", expanded=False):
     )
     height = st.number_input("Map height (px)", 1, 10000, 600, 1)
 
-geometry_gdf = input_gdf[input_gdf.index == input_geometry_idx]
+geometry_gdf = input_gdf[input_gdf.index == 0]
 
 
 def check_valid_geometry(geometry_gdf):