intermediate transform

map_tab/map_logic.py

@@ -114,7 +114,7 @@ def make_map(city, show_grid, show_georef):
 
 
 def _add_grid_overlay_plotly(fig, transformer):
-    """Add grid overlay as filled polygons on the Plotly map."""
+    """Add grid overlay as filled polygons on the Plotly map with intermediate EPSG:3857 transform."""
     grid_values = []
 
     for fname in os.listdir(OUTPUT_DIR):
@@ -164,9 +164,16 @@ def _add_grid_overlay_plotly(fig, transformer):
                 y0 = tile_ymin + r * CELL_SIZE_M
                 x1 = x0 + CELL_SIZE_M
                 y1 = y0 + CELL_SIZE_M
-                
-                lon0, lat0 = transformer.transform(x0, y0)
-                lon1, lat1 = transformer.transform(x1, y1)
+
+                # --- Intermediate transform to EPSG:3857 ---
+                transformer_3857 = pyproj.Transformer.from_crs(transformer.source_crs, "EPSG:3857", always_xy=True)
+                x0_3857, y0_3857 = transformer_3857.transform(x0, y0)
+                x1_3857, y1_3857 = transformer_3857.transform(x1, y1)
+
+                # --- Then transform from EPSG:3857 to EPSG:4326 for Plotly ---
+                lon0, lat0 = pyproj.Transformer.from_crs("EPSG:3857", "EPSG:4326", always_xy=True).transform(x0_3857, y0_3857)
+                lon1, lat1 = pyproj.Transformer.from_crs("EPSG:3857", "EPSG:4326", always_xy=True).transform(x1_3857, y1_3857)
+
                 lons = [lon0, lon1, lon1, lon0, lon0]
                 lats = [lat0, lat0, lat1, lat1, lat0]
                 fig.add_trace(go.Scattermapbox(
@@ -179,3 +186,4 @@ def _add_grid_overlay_plotly(fig, transformer):
                     hoverinfo="text",
                     text=f"{val:.2f}"
                 ))
+