Tutorial: Create data

Prepare data

You will access the Trailheads feature layer created in the Import Data tutorial. You can also create a blank online layer using the Developers Dashboard or ArcGIS Online, see Create a new feature layer for detailed steps.

Import modules and log in

1. Import the GIS class from the arcgis.gis module. Use the GIS class to Log in using your ArcGIS Online or Developer account.

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   from arcgis.gis import GIS
   import getpass
   
   
   gis = GIS(
       url="https://www.arcgis.com",
       username="username",
       password=getpass.getpass("Enter password:"),
   )
   
   

Access the feature layer

1. Use the content property to search for the Trailheads feature layer you created in the Import Data tutorial.

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   gis = GIS(
       url="https://www.arcgis.com",
       username="username",
       password=getpass.getpass("Enter password:"),
   )
   
   query = f'title: Trailheads*" AND type: "Feature Service" AND owner:{gis.properties.user.username}'
   search_results = gis.content.search(query=query, max_items=10)
   search_results
   
   

2. Find the Trailheads feature layer from the list of results, and display the URL of the item. The index for the specific layer may be different in your organization.

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   query = f'title: Trailheads*" AND type: "Feature Service" AND owner:{gis.properties.user.username}'
   search_results = gis.content.search(query=query, max_items=10)
   search_results
   
   myPoints_item = search_results[0]
   myPoints_item.url
   
   

3. Access the list of layers in the feature layer, and assign to a new variable named points_layer.

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   query = f'title: Trailheads*" AND type: "Feature Service" AND owner:{gis.properties.user.username}'
   search_results = gis.content.search(query=query, max_items=10)
   search_results
   
   myPoints_item = search_results[0]
   myPoints_item.url
   
   feature_layers = myPoints_item.layers
   points_layer = feature_layers[0]
   points_layer.properties.name
   
   

4. List the field names and field types by enumerating through the fields using the layer properties.

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   feature_layers = myPoints_item.layers
   points_layer = feature_layers[0]
   points_layer.properties.name
   
   for field in points_layer.properties["fields"]:
       print(f"Name: {field['name']}, type: {field['type']}")
   
   

Create an edit function

1. Write a callback function for the map widget's on_click method. Import the features and geometry modules. You will use the geometry module to create a Point geometry object from the location clicked on the map. Use the features module to create a Feature object from this point to add to the feature layer. Use the draw method on the map to temporarily display the new point in the map.

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   for field in points_layer.properties["fields"]:
       print(f"Name: {field['name']}, type: {field['type']}")
   
   from arcgis import features
   from arcgis import geometry
   import random
   
   
   def create_feature(_map, location):
       try:
           oid = 1
           point = geometry.Point(location)
           feature = features.Feature(
               geometry=point,
               attributes={
                   "TRL_NAME": "My Trailhead",
                   "TRL_ID": random.sample(range(-32768, 32767), 1)[0],
               },
           )
   
           points_layer.edit_features(adds=[feature])
           _map.draw(point)
       except Exception as ex:
           print(f"could not create feature. {str(ex)}")
   
   
   
   

Create the map

1. Pass the create_feature function as a parameter to the map widget's on_click method. Run the cell and begin clicking locations on the map. When you click at a location on the map, Point and Feature object are constructed. The Feature is rendered as a graphic marker on the map. The Feature is then added to feature layer through the edit process.

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   from arcgis import features
   from arcgis import geometry
   import random
   
   
   def create_feature(_map, location):
       try:
           oid = 1
           point = geometry.Point(location)
           feature = features.Feature(
               geometry=point,
               attributes={
                   "TRL_NAME": "My Trailhead",
                   "TRL_ID": random.sample(range(-32768, 32767), 1)[0],
               },
           )
   
           points_layer.edit_features(adds=[feature])
           _map.draw(point)
       except Exception as ex:
           print(f"could not create feature. {str(ex)}")
   
   
   
   m = gis.map()
   m
   
   # wait for the map to load, and then add the following:
   m.center = [34.09042, -118.71511]
   m.zoom = 11
   m.on_click(create_feature)
   
   

2. Clear the map graphics. Clear the graphic markers from the map so that in the subsequent step you can add the feature layer and see the features created by clicking locations.

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   m = gis.map()
   m
   
   # wait for the map to load, and then add the following:
   m.center = [34.09042, -118.71511]
   m.zoom = 11
   m.on_click(create_feature)
   
   m.clear_graphics()
   
   

3. Add the layer to the map to visualize features.

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   m = gis.map()
   m
   
   # wait for the map to load, and then add the following:
   m.center = [34.09042, -118.71511]
   m.zoom = 11
   m.on_click(create_feature)
   
   m.clear_graphics()
   
   m.add_layer(points_layer)

You should see the new feature displayed on the map.