The GIS is a warehouse of geographic content and services. ArcGIS includes several classes to make use of this content, publish new items and update them when needed. This sample on updating the content of web maps and web scenes will demonstrate the following
- Replace web layers of a web map. For instance, you can use this to update a web map when the services it points to were deleted. The sample shows how to Create a web feature layer as a FeatureService object and perform operations on it.
- Drive the map widget by code. In addition to displaying the interactive map widget, you can also set it to load at a particular extent. This is great for presentation purposes. During this process, the sample shows how to create and use a Map object.
- Make a copy of a public web scene item into your contents and then update it.
- Edit the list of layers to remove unnecessary ones.
- Replace the basemap of the web scene.
from arcgis.gis import GIS, ItemTypeEnum
from arcgis.map import Map, Scene
from IPython.display import display
gis = GIS(profile="your_online_profile")Creating a web map and feature layer
We will will create a feature layer and a web map. We will then delete the feature layer and re-publish. This will change the service and leave us with a broken layer inside our map, don't worry we will fix this in the next steps.
Create a feature layer
my_csv = 'data/updating_gis_content/capitals_1.csv'
item_prop = {'title':'USA Capitals spreadsheet for WebMap', 'type':'CSV'}folder = gis.content.folders.get()
csv_item = folder.add(item_properties = item_prop, file=my_csv).result()
CSV by python_user
feature_service_list = gis.content.search("title:'USA Capitals spreadsheet for WebMap' , type:Feature Service")In the cell below we are publishing the csv_item. But before we do that we should check if the csv_item is already published. If it's already published then we'll not publish it again and retrieve the already published item
capitals_item = None
if not feature_service_list:
capitals_item = csv_item.publish()
else:
capitals_item = feature_service_list[0]capitals_item
Feature Layer Collection by python_user
Create WebMap, Add Layer, and Save
wm = Map()
wm.content.add(capitals_item)
wm.save({"title": "USA Capitals WebMap", "tags": ["python", "webmap"], "snippet": "A webmap that contains USA capitals as a feature layer."})
Web Map by python_user
Delete Feature Layer and re-publish
In the following cell we'll delete the capitals_item to demonstrates how some feature layers can get deleted without us realizing that they are part of webmaps.
capitals_item.delete(permanent=True)True
In the upcoming cells we will get the webmap and see that the layer does not show up!
This sample can then guide you to fix this problem of missing layers.
Using and updating a web map
We will search for that web map that has broken layers, render it on the notebook and update it.
search_result = gis.content.search("title:USA Capitals WebMap", item_type = "Web Map")
display(search_result)[<Item title:"USA Capitals" type:Web Map owner:arcgis_python>]
Read the web map as a WebMap object
wm_item = search_result[0]
web_map_obj = Map(item=wm_item)web_map_obj
Fix errors in web map
The widget loads an empty web map with just a basemap. Let us investigate the contents of the web map to determine the issue. You can query the layers in the web map using the layers property of MapContent class
web_map_obj.content.layers[<FeatureLayer url:"https://services7.arcgis.com/JEwYeAy2cc8qOe3o/arcgis/rest/services/USA_Capitals_spreadsheet_for_WebMap/FeatureServer/0">]
The above layer is just a basemap layer and there are no feature layers in the content layers list
Update the web map
To update the web map, we call the update() method. You have the option to update the thumbnail or any other item properties at this time.
new_capitals = csv_item.publish()
new_capitals 
web_map_obj.update(item_properties={'title':'USA Capitals - updated'},
thumbnail = "./data/webmap_thumbnail.png")True
Now we see that the web map is is rendering the layer properly after re-publishing the item
web_map_obj
The web map was sucessfully overwritten with correct operational layers. You can interact with the widget and zoom into the USA to observe the locations of capitals. Let's clean it up so we can always run this notebook again
wm_item.delete(permanent=True)
new_capitals.delete(permanent=True)
csv_item.delete(permanent=True)True
Using and updating a web scene
In the sample above we observed how to use and update a web map. Updating the web scene is similar, we use the Scene class. Let us look at the example of a web scene that displays tropical cyclones over the Pacific ocean.
search_result = gis.content.search('title:Western Pacific Typhoons (2005) by esri_3d',
item_type = 'Web Scene')
web_scene_item = search_result[0]
web_scene_item
Web Scene by tkukreja_geosaurus
Lets display the web scene in the notebook.
web_scene_obj = Scene(item=web_scene_item)
web_scene_objweb_scene_obj = Scene(item=web_scene_item)
web_scene_obj
This is a great web scene and it displays a lot of hurricane tracks. However, we want to create a new one with only a particular subset of data and customize the basemaps. To modify this web scene, let us first make a copy of it and publish it into your portal.
Make a copy of the public web scene item
Let's say, we are only interested in the storms that occur in summer. Summer in tropical Asia is around April-June and that matches with a layer in the existing web scene. We will use the layers property of SceneContent class to understand how the layers look like.
Update layers of new web scene
layers_list = web_scene_obj.content.layers
layers_list[<FeatureLayer url:"https://services.arcgis.com/P3ePLMYs2RVChkJx/arcgis/rest/services/PacificTyphoons2005_WFL/FeatureServer/18">, Group Layer: October - December, Group Layer: September, Group Layer: August, Group Layer: July, Group Layer: April - June, Group Layer: January - March]
If you notice, some of the layers above are group layers, meaning, they contain sub layers.
We are only interested in the layers that correspond to cyclones in summer. We will remove the layers except the April-June layer using the remove() method
web_scene_obj.content.remove(1)
web_scene_obj.content.remove(1)
web_scene_obj.content.remove(1)
web_scene_obj.content.remove(1)
web_scene_obj.content.remove(2)True
In the cell below we see that there is only two layers the basemap layer and the April-June layer
web_scene_obj.content.layers[<FeatureLayer url:"https://services.arcgis.com/P3ePLMYs2RVChkJx/arcgis/rest/services/PacificTyphoons2005_WFL/FeatureServer/18">, Group Layer: April - June]
new_web_scene_obj = web_scene_objnew_web_scene_obj.content.layers[<FeatureLayer url:"https://services.arcgis.com/P3ePLMYs2RVChkJx/arcgis/rest/services/PacificTyphoons2005_WFL/FeatureServer/18">, Group Layer: April - June]
Update basemap of new web scene
We now have the necessary layers information. Let us also try to change the basemap to a darker shade.
Basemaps are web maps that are stored in a group usually called Basemaps. We will be using 3d basemaps for scenes, which we will get using the property called basemaps3d of BasemapManager class
new_web_scene_obj.basemap.basemap{'baseMapLayers': [{'id': '73e9780a7d6f413f8547abbd19ec786c',
'layerType': 'ArcGISTiledMapServiceLayer',
'listMode': 'show',
'opacity': 1.0,
'refreshInterval': 0.0,
'title': 'World Topo Map',
'url': 'https://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer',
'visibility': True}],
'title': 'Topographic'}new_web_scene_obj.basemap.basemaps3d['topo-3d', 'navigation-3d', 'streets-3d', 'osm-3d', 'gray-3d', 'navigation-dark-3d', 'streets-dark-3d', 'dark-gray-3d']
new_web_scene_obj.basemap.basemap = 'gray-3d'new_web_scene_obj.basemap.basemap{'baseMapLayers': [{'id': 'gray-3d-base-layer',
'layerType': 'VectorTileLayer',
'opacity': 1.0,
'styleUrl': 'https://www.arcgis.com/sharing/rest/content/items/01a14b466345455ba4176d2e6390db92/resources/styles/root.json',
'title': 'Streets',
'visibility': True}],
'title': 'Gray 3D'}Now that we have performed the necessary updates, we can go ahead and publish this as a new web scene item on our portal. We will use the save() method of the Scene class to create a new Scene. Previously we used the update() method to update the web map which updates the existing web map as opposed to creating a new web map
web_scene_data_item_prop = {'title':'Tropical Cyclones - Summer',
'tags' : 'ArcGIS Python API',
'snippet' : str.format('Subset of <a href={2}>{0}</a> published by {1}',
web_scene_item.title, web_scene_item.owner,
"https://www.arcgis.com/home/item.html?id=" + web_scene_item.id),
}
web_scene_data_item = new_web_scene_obj.save(item_properties=web_scene_data_item_prop)
web_scene_data_itemWe have successfully published the new web scene. Now let us display in an interactive widget and observe if it has the necessary updates.
new_web_scene_obj = Scene(item = web_scene_data_item)
new_web_scene_obj
Summary
In this sample, we observed how to consume web maps, web scenes and how to update and save them. During this process, the sample showed how to read web feature layers, how to modify the map widget using code, how to delete layers of a Scene and how to look for and set 3d basemaps