Save Draw Data Example¶

This notebook demonstrates the new save_draw_data() method in AnyMap, which allows you to save drawn features to various file formats supported by GeoPandas.

Installation Requirements¶

The save_draw_data method requires GeoPandas to be installed:

pip install geopandas

Basic Usage¶

First, let's create a map and add a draw control:

In [ ]:

from anymap.maplibre import MapLibreMap
import tempfile
import os

# Create a map centered on New York City
m = MapLibreMap(center=[-74.0, 40.7], zoom=10)
m.add_basemap("OpenStreetMap.Mapnik")

# Add a draw control so users can draw features
m.add_draw_control(
    position="top-left",
    controls={"point": True, "line_string": True, "polygon": True, "trash": True},
)

m

from anymap.maplibre import MapLibreMap import tempfile import os # Create a map centered on New York City m = MapLibreMap(center=[-74.0, 40.7], zoom=10) m.add_basemap("OpenStreetMap.Mapnik") # Add a draw control so users can draw features m.add_draw_control( position="top-left", controls={"point": True, "line_string": True, "polygon": True, "trash": True}, ) m

Adding Sample Data¶

Let's add some sample features for demonstration:

In [ ]:

# Add some sample drawn features
sample_features = {
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "properties": {"name": "Central Park", "type": "park"},
            "geometry": {"type": "Point", "coordinates": [-73.9665, 40.7812]},
        },
        {
            "type": "Feature",
            "properties": {"name": "Brooklyn Bridge", "type": "landmark"},
            "geometry": {"type": "Point", "coordinates": [-73.9969, 40.7061]},
        },
        {
            "type": "Feature",
            "properties": {"name": "Manhattan Area", "type": "area"},
            "geometry": {
                "type": "Polygon",
                "coordinates": [
                    [
                        [-74.02, 40.70],
                        [-73.93, 40.70],
                        [-73.93, 40.80],
                        [-74.02, 40.80],
                        [-74.02, 40.70],
                    ]
                ],
            },
        },
    ],
}

# Load the sample data into the draw control
m.load_draw_data(sample_features)

print(f"Loaded {len(m.get_draw_data()['features'])} features")

# Add some sample drawn features sample_features = { "type": "FeatureCollection", "features": [ { "type": "Feature", "properties": {"name": "Central Park", "type": "park"}, "geometry": {"type": "Point", "coordinates": [-73.9665, 40.7812]}, }, { "type": "Feature", "properties": {"name": "Brooklyn Bridge", "type": "landmark"}, "geometry": {"type": "Point", "coordinates": [-73.9969, 40.7061]}, }, { "type": "Feature", "properties": {"name": "Manhattan Area", "type": "area"}, "geometry": { "type": "Polygon", "coordinates": [ [ [-74.02, 40.70], [-73.93, 40.70], [-73.93, 40.80], [-74.02, 40.80], [-74.02, 40.70], ] ], }, }, ], } # Load the sample data into the draw control m.load_draw_data(sample_features) print(f"Loaded {len(m.get_draw_data()['features'])} features")

Saving to Different Formats¶

Now let's demonstrate saving the drawn data to various formats:

Save to GeoJSON¶

GeoJSON is the most common format for web mapping and supports all geometry types:

In [ ]:

# Save to GeoJSON format
geojson_path = "/tmp/drawn_features.geojson"
m.save_draw_data(geojson_path)

print(f"✓ Saved to GeoJSON: {geojson_path}")
print(f"File size: {os.path.getsize(geojson_path)} bytes")

# Save to GeoJSON format geojson_path = "/tmp/drawn_features.geojson" m.save_draw_data(geojson_path) print(f"✓ Saved to GeoJSON: {geojson_path}") print(f"File size: {os.path.getsize(geojson_path)} bytes")

Save to GeoPackage¶

GeoPackage is a modern, standards-based format that supports mixed geometry types:

In [ ]:

# Save to GeoPackage format
gpkg_path = "/tmp/drawn_features.gpkg"
m.save_draw_data(gpkg_path)

print(f"✓ Saved to GeoPackage: {gpkg_path}")
print(f"File size: {os.path.getsize(gpkg_path)} bytes")

# Save to GeoPackage format gpkg_path = "/tmp/drawn_features.gpkg" m.save_draw_data(gpkg_path) print(f"✓ Saved to GeoPackage: {gpkg_path}") print(f"File size: {os.path.getsize(gpkg_path)} bytes")

Save to Shapefile (Points Only)¶

Shapefiles require all features to have the same geometry type. Let's create a map with only points:

In [ ]:

# Create a new map with only point features
m_points = MapLibreMap(center=[-74.0, 40.7], zoom=10)
m_points.add_basemap("OpenStreetMap.Mapnik")
m_points.add_draw_control()

# Add only point features
point_features = {
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "properties": {"name": "Central Park", "type": "park"},
            "geometry": {"type": "Point", "coordinates": [-73.9665, 40.7812]},
        },
        {
            "type": "Feature",
            "properties": {"name": "Brooklyn Bridge", "type": "landmark"},
            "geometry": {"type": "Point", "coordinates": [-73.9969, 40.7061]},
        },
    ],
}

m_points.load_draw_data(point_features)

# Now save to shapefile
shp_path = "/tmp/drawn_points.shp"
m_points.save_draw_data(shp_path)

print(f"✓ Saved points to Shapefile: {shp_path}")
print(
    f"Files created: {[f for f in os.listdir('/tmp') if f.startswith('drawn_points.')]}"
)

m_points

# Create a new map with only point features m_points = MapLibreMap(center=[-74.0, 40.7], zoom=10) m_points.add_basemap("OpenStreetMap.Mapnik") m_points.add_draw_control() # Add only point features point_features = { "type": "FeatureCollection", "features": [ { "type": "Feature", "properties": {"name": "Central Park", "type": "park"}, "geometry": {"type": "Point", "coordinates": [-73.9665, 40.7812]}, }, { "type": "Feature", "properties": {"name": "Brooklyn Bridge", "type": "landmark"}, "geometry": {"type": "Point", "coordinates": [-73.9969, 40.7061]}, }, ], } m_points.load_draw_data(point_features) # Now save to shapefile shp_path = "/tmp/drawn_points.shp" m_points.save_draw_data(shp_path) print(f"✓ Saved points to Shapefile: {shp_path}") print( f"Files created: {[f for f in os.listdir('/tmp') if f.startswith('drawn_points.')]}" ) m_points

Error Handling¶

The save_draw_data method provides helpful error messages for common issues:

Mixed Geometry Types in Shapefile¶

Let's see what happens when we try to save mixed geometry types to a shapefile:

In [ ]:

# Try to save mixed geometry types to shapefile
try:
    m.save_draw_data("/tmp/mixed_geometries.shp")
except ValueError as e:
    print(f"Expected error: {e}")

# Try to save mixed geometry types to shapefile try: m.save_draw_data("/tmp/mixed_geometries.shp") except ValueError as e: print(f"Expected error: {e}")

No Features to Save¶

Let's see what happens when there are no drawn features:

In [ ]:

# Create a map with no drawn features
empty_map = MapLibreMap(center=[0, 0], zoom=2)

try:
    empty_map.save_draw_data("/tmp/empty.geojson")
except ValueError as e:
    print(f"Expected error: {e}")

# Create a map with no drawn features empty_map = MapLibreMap(center=[0, 0], zoom=2) try: empty_map.save_draw_data("/tmp/empty.geojson") except ValueError as e: print(f"Expected error: {e}")

Loading Saved Data¶

You can load the saved data back into a map or use it with other geospatial tools:

In [ ]:

import json

# Create a new map and load the saved GeoJSON data
m_new = MapLibreMap(center=[-74.0, 40.7], zoom=10)
m_new.add_basemap("OpenStreetMap.Mapnik")
m_new.add_draw_control()

# Load the saved data
with open(geojson_path, "r") as f:
    saved_data = json.load(f)

m_new.load_draw_data(saved_data)
print(f"Loaded {len(m_new.get_draw_data()['features'])} features from saved file")

m_new

import json # Create a new map and load the saved GeoJSON data m_new = MapLibreMap(center=[-74.0, 40.7], zoom=10) m_new.add_basemap("OpenStreetMap.Mapnik") m_new.add_draw_control() # Load the saved data with open(geojson_path, "r") as f: saved_data = json.load(f) m_new.load_draw_data(saved_data) print(f"Loaded {len(m_new.get_draw_data()['features'])} features from saved file") m_new

Working with GeoPandas¶

Since the save method uses GeoPandas, you can also work directly with the data:

In [ ]:

import geopandas as gpd

# Read the saved GeoJSON with GeoPandas
gdf = gpd.read_file(geojson_path)

print("GeoPandas DataFrame:")
print(gdf)
print(f"\nCRS: {gdf.crs}")
print(f"Geometry types: {gdf.geometry.geom_type.unique()}")

import geopandas as gpd # Read the saved GeoJSON with GeoPandas gdf = gpd.read_file(geojson_path) print("GeoPandas DataFrame:") print(gdf) print(f"\nCRS: {gdf.crs}") print(f"Geometry types: {gdf.geometry.geom_type.unique()}")

Supported Formats¶

The save_draw_data method supports all formats that GeoPandas can write to, including:

• GeoJSON (.geojson) - Best for web applications, supports all geometry types
• GeoPackage (.gpkg) - Modern SQLite-based format, supports all geometry types
• Shapefile (.shp) - Traditional GIS format, requires same geometry type for all features
• KML (.kml) - Google Earth format
• GML (.gml) - OGC Geography Markup Language
• CSV (.csv) - Only for point data without geometry

You can also specify the driver explicitly:

m.save_draw_data("output.gpkg", driver="GPKG")
m.save_draw_data("output.shp", driver="ESRI Shapefile")

Cleanup¶

Clean up the temporary files:

In [ ]:

# Clean up temporary files
import glob

for pattern in ["/tmp/drawn_features.*", "/tmp/drawn_points.*"]:
    for file in glob.glob(pattern):
        try:
            os.remove(file)
            print(f"Removed {file}")
        except:
            pass

# Clean up temporary files import glob for pattern in ["/tmp/drawn_features.*", "/tmp/drawn_points.*"]: for file in glob.glob(pattern): try: os.remove(file) print(f"Removed {file}") except: pass

Summary¶

The save_draw_data() method provides a simple way to export drawn features from AnyMap to various geospatial file formats:

1. Easy to use: Just call map.save_draw_data("filename.geojson")
2. Multiple formats: Supports all GeoPandas-compatible formats
3. Error handling: Provides helpful error messages for common issues
4. Format detection: Automatically detects format from file extension
5. CRS handling: Automatically sets EPSG:4326 if no CRS is present

This makes it easy to integrate drawn features with other geospatial workflows and tools!