Using the GIS¶
GIS object in the
gis module is the most important object when working with the ArcGIS API for Python. The GIS object represents the GIS you are working with, be it ArcGIS Online or an instance of ArcGIS Enterprise. You use the GIS object to consume and publish GIS content and administrators may use it to manage GIS users, groups and datastores. This object becomes your entry point in your Python script when using the API.
To use the GIS object, import GIS from the
from arcgis.gis import GIS
To create the GIS object, we pass in the url and our login credentials as shown below:
gis = GIS('home')
Below, we're connecting to ArcGIS Online (the default GIS used when the url is not provided) as an anonymous user:
gis = GIS()
Adding a '?' mark after an object and querying it brings up help for that object in the notebook:
The notebook provides intellisense and code-completion. Typing a dot after an object and hitting tab brings up a drop-down with its properties and methods:
GIS object provides helper objects to manage the GIS resources, i.e. the users, groups, content and datastores. These helper utilities are in the form of helper objects named:
datastore respectively. The helper utility for managing user roles named
roles is available as a property on the helper object
Each such helper object has similar patterns of usage: there are methods to
create() the respective resources.
The prescribed programming pattern is to not create the GIS resources (user, group, item, role, datastore) directly using their constructor, but to access them through their corresponding helper objects described above.
Thus, to access a user, you would use the
users property of your
gis object which gives you an instance of
UserManager class. You would then call the
get() method of the
UserManager object and pass the user name of the user you are interested in.
user = gis.users.get('john.smith')
Rich IDE experience with Jupyter notebooks¶
The ArcGIS API for Python is integrated with Jupyter Notebook to make it easy to visualize and interact with GIS resources. The
user object has a rich representation that can be queried like this:
The resources are implemented as Python dictionaries. You can query for the resource properties using the
The properties are also available as properties on the resource object, so you can use the dot notation to access them:
The resources provide methods to
delete() and use the object. The reminder of topics in this module talk in detail about using the various helper objects and resource objects.
Embedded maps in Jupyter notebooks¶
GIS object includes a map widget that can be used to visualize the content of your GIS as well as see the results of your analysis. Let's bring up a map of Palm Springs, CA:
map1 = gis.map("Palm Springs, CA") map1
We can search for content in our GIS. Let's search for Hiking Trails in the Palm Springs region. We do that by calling
gis.content.search() and for each web map or web layers that gets returned, we can display its rich representation within the notebook:
from IPython.display import display items = gis.content.search('Palm Springs Trails') for item in items: display(item)
We can then add the returned web layers to our map. To add the last layer returned above, we call the
add_layer() method and pass in the layer for Palm Springs Trail:
# Let us filter out the item with title 'Trails' that we want to add item_to_add = [temp_item for temp_item in items if temp_item.title == "Trails"] map1.add_layer(item_to_add)
The above cell updated the map widget, if you scroll to the top, you can notice a new trail layer being rendered on the map.
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