Add real OpenStreetMap tiles to PDF export

Features:
- Use contextily library to add real OSM basemap tiles
- Map now shows actual streets, buildings, and geography
- Larger, higher resolution map (7x5.5 inches, 200 DPI)
- Improved marker styling (white borders, larger size)
- Legend positioned outside plot area
- OSM attribution added
- Graceful fallback to grid if tiles unavailable

Map now matches dashboard Leaflet map appearance

Dependencies added:
- contextily>=1.3.0 (for OpenStreetMap tiles)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/utils/pdf_export.py

@@ -14,6 +14,11 @@ import matplotlib
 matplotlib.use('Agg')  # Use non-interactive backend
 import matplotlib.pyplot as plt
 import numpy as np
+try:
+    import contextily as cx
+    HAS_CONTEXTILY = True
+except ImportError:
+    HAS_CONTEXTILY = False
 
 
 class DashboardPDFExporter:
@@ -255,7 +260,7 @@ class DashboardPDFExporter:
         return table
 
     def _create_map(self, geotagged_submissions, categories):
-        """Create geographic distribution map using matplotlib"""
+        """Create geographic distribution map with real OpenStreetMap tiles"""
         if not geotagged_submissions:
             return None
 
@@ -266,7 +271,7 @@ class DashboardPDFExporter:
             cats = [s.category for s in geotagged_submissions]
 
             # Create matplotlib figure
-            fig, ax = plt.subplots(figsize=(8, 6))
+            fig, ax = plt.subplots(figsize=(10, 8))
 
             # Color map for categories
             category_colors = {
@@ -283,24 +288,49 @@ class DashboardPDFExporter:
                 cat_lats = [lat for lat, cat in zip(lats, cats) if cat == category]
                 cat_lons = [lon for lon, cat in zip(lons, cats) if cat == category]
                 color = category_colors.get(category, '#95a5a6')
-                ax.scatter(cat_lons, cat_lats, c=color, label=category, s=100, alpha=0.7, edgecolors='black')
-
-            ax.set_xlabel('Longitude', fontsize=11, fontweight='bold')
-            ax.set_ylabel('Latitude', fontsize=11, fontweight='bold')
-            ax.set_title('Geographic Distribution of Submissions', fontsize=14, fontweight='bold')
-            ax.legend(loc='best', fontsize=9)
-            ax.grid(True, alpha=0.3)
+                ax.scatter(cat_lons, cat_lats, c=color, label=category,
+                          s=150, alpha=0.8, edgecolors='white', linewidths=2, zorder=5)
+
+            # Add OpenStreetMap basemap if contextily is available
+            if HAS_CONTEXTILY:
+                try:
+                    # Add map tiles
+                    cx.add_basemap(ax, crs='EPSG:4326', source=cx.providers.OpenStreetMap.Mapnik,
+                                  attribution=False, alpha=0.8)
+                except Exception as e:
+                    print(f"Could not add basemap: {e}")
+                    # Fallback to grid
+                    ax.grid(True, alpha=0.3)
+            else:
+                # Fallback: simple grid
+                ax.grid(True, alpha=0.3)
+
+            ax.set_xlabel('Longitude', fontsize=12, fontweight='bold')
+            ax.set_ylabel('Latitude', fontsize=12, fontweight='bold')
+            ax.set_title('Geographic Distribution of Submissions',
+                        fontsize=16, fontweight='bold', pad=20)
+
+            # Legend outside plot area
+            ax.legend(loc='upper left', bbox_to_anchor=(1.02, 1),
+                     fontsize=10, frameon=True, fancybox=True, shadow=True)
+
+            # Add attribution text if using OpenStreetMap
+            if HAS_CONTEXTILY:
+                fig.text(0.99, 0.01, '© OpenStreetMap contributors',
+                        ha='right', va='bottom', fontsize=7, style='italic', alpha=0.7)
 
             # Convert to image
             img_buffer = io.BytesIO()
             plt.tight_layout()
-            plt.savefig(img_buffer, format='png', dpi=150, bbox_inches='tight')
+            plt.savefig(img_buffer, format='png', dpi=200, bbox_inches='tight')
             plt.close(fig)
             img_buffer.seek(0)
 
-            img = Image(img_buffer, width=6*inch, height=4.5*inch)
+            img = Image(img_buffer, width=7*inch, height=5.5*inch)
             return img
 
         except Exception as e:
             print(f"Error creating map: {e}")
+            import traceback
+            traceback.print_exc()
             return None

requirements.txt

@@ -22,3 +22,4 @@ nltk>=3.8.0
 
 # PDF generation
 reportlab>=4.0.0
+contextily>=1.3.0