Licensing options for this format begin with FME Professional Edition.
Note: Google is ending support for Google Maps Engine on January 29, 2016. All Google Maps Engine functionality may stop working after this date.
The Google Maps Engine Tables Reader/Writer plug-in enables FME to read, create, update, and delete vector table features on Google Maps Engine.
Overview
Google Maps Engine is a platform for publishing custom maps through Google’s cloud infrastructure. Data uploaded to Google Maps Engine can then be published and visualized in Google Maps.
Google Maps Engine contains multiple resource types, including Assets, Layers, Maps, Projects, Rasters, and Vector Tables. This plug-in supports reading, writing, and creating Vector Tables.
FME also offers a Google Maps Engine Raster Writer for writing raster assets.
Note: The Google Maps Engine Tables Reader/Writer uses the Google Maps Engine API. This API is only accessible to users with an active Maps Engine account. Google Maps Engine Lite accounts cannot be accessed using this reader/writer.
Google Maps Engine may only be accessed over HTTPS. If you are connecting via a proxy server, ensure that it supports HTTPS.
Duplicate Table Names
Google Maps Engine allows for duplicate table names. The Google Maps Engine Tables Reader/Writer will try to match feature types with a unique table name.
If multiple tables share the same name as the feature type, the translation will abort. To resolve this ambiguity, feature types can be set to the unique Asset ID that identifies each table.
To obtain the Asset ID for a table: Open the details page for the table in the Google Maps Engine web interface, and click the Asset ID link.
API Limits
Reading and writing using the Google Maps Engine Tables plug-in will consume map load quotas from your account. Learn more about map loads and quotas.
The Google Maps Engine API is subject to usage limits:
- The Google Maps Engine reader/writer will perform exponential back-off in response to rate-limiting and “backendError” responses from the server.
- The Google Maps Engine writer will put features into batched requests in order to obey the API limit of 50 features per request.
For more information, see http://developers.google.com/maps-engine/documentation/limits.
The Google Maps Engine API has feature complexity limits. These include:
- the number of vertices per feature
- the number of vertices per vector table
- the number of features per vector table
- the number of attributes per vector table
- the length of attribute names
- the length of string attribute values
Refer to the Google Maps Engine API documentation and http://support.google.com/mapsengine/answer/1272933?hl=en#vectorFiles for information on these limits.
Authentication
Google Maps Engine uses OAuth 2.0 authentication. The Google Maps Engine Table reader/writer accepts a Refresh Token directive instead of a username and password.
Terminology
In FME, a Google Maps Engine table is a feature type, a Google Maps Engine feature is an FME feature, and a Google Maps Engine feature property is a user attribute.
To obtain a refresh token: Click the browse button next to the Refresh Token field in the reader or writer parameters dialog.
It is recommended that you save the defaults (from the Defaults button on the dialog) once the refresh token is retrieved so you will not have to re-authenticate in the future. You will need to re-add the reader or writer to older workspaces so they will run properly.