Create Rendering Plugins

HERE platform catalogs contain layers with location data that is mostly partitioned geographically. The Data Inspector Library allows rendering Protobuf-encoded, geographically partitioned data on top of the base map with the help of custom GeoJSON rendering plugins.

The Data Inspector Library uses Protocol Buffers (schemas) to decode these partitions. A partition is rendered with a plugin that is invoked once the partition is decoded. The rendering plugin returns the GeoJSON representation of the partition that is then rendered by the GeoJsonDataSource. The Platform lets you attach a GeoJSON plugin to your schema.

For a full list of GeoJSON features supported by the Data Inspector Library, see Preconditions for Visualization.

With the rendering functions and style properties provided with the Data Inspector Library, you can develop your custom GeoJSON rendering plugins using one of the following environments:

• HERE platform Data Inspector: In the HERE platform portal, go to a layer's details' page and select the Inspect tab.

  For this option to work, you do not need to install Node.js, additional Data Inspector Library modules, or any third-party components. Just log in to the portal with your platform credentials.

• Data Inspector online standalone tool: An online standalone tool hosted on the HERE platform that makes it easy for you to write a rendering plugin for your schema so that the data can be visualized.

  No installations are needed, you just upload a local partition file, specify a schema (local or HRN), and write and test your plugin.

• Local Data Inspector: For this option to work, you need to install Node.js and the Data Inspector Library along with the example applications.

To see a sample implementation of the Data Inspector Library rendering functions and style properties, see the Plugin Examples chapter.

Use Cases

Rendering plugins enable you to solve the following typical use cases:

• When you are developing a pipeline, a schema, or a dataset and need a rendering plugin to quickly visualize the outputs of your data pipelines on top of the base map.

  In this case, for a custom layer schema that has no GeoJSON plugin, you are provided with a predefined plugin JS template. The template contains detailed inline instructions where to put your code in the embedded editor.

• When you are working with the data in a catalog layer and need to temporarily change the existing visualization to answer your specific questions about the data.

  In this case, you can modify the rendering plugin bundled with the original layer schema in the editor and run the code right away to inspect the output in the Data Inspector's Map View.

Later, once you are satisfied with the plugin’s behavior, you can download the plugin locally, bundle the plugin with your schema, and publish the schema to the platform to use it with the layer. To create or extend a schema, a Maven Archetype is provided. For more information, see Create and Extend Schemas.