Join tabular and vector data sources (client-side region mapping)

[Nick Forbes-Smith]

It would be great to be able to join tabular datasets with vector datasets by column.

This would present data in a similar way to region mapping - where we "join" tabular dataset with vector tile datasets.

For example

• GeoJSON of City of Melbourne CLUE blocks - https://data.melbourne.vic.gov.au/api/explore/v2.1/catalog/datasets/blocks-for-census-of-land-use-and-employment-clue/exports/geojson?lang=en&timezone=Australia%2FSydney (is 300KB)
• CSV of jobs in Melbourne by type by CLUE Block - https://data.melbourne.vic.gov.au/api/explore/v2.1/catalog/datasets/employment-by-block-by-anzsic/exports/csv?lang=en&timezone=Australia%2FSydney&use_labels=true&delimiter=%2C (is 700KB)

We would join by "Block ID"

[Nick Forbes-Smith]

This would be cool

• Create a new vector-join catalog item - which extends GeoJsonMixin
• Add members property that allows you to define catalog items to merge
  • These can be GeoJsonMixin or TableMixin catalog items
  • Or, IDs to existing models (in the catalog)
• Have some sort of joinBy trait
• Merge all the rows/features into a new GeoJson Feature collection
• That's it

This means you can use any tabular or geojson source to merge - for example

• Opendatasoft table
• GeoJSON polygons

Or

• CSV time-series
• ArcGis FeatureService

It also means you don't need to modify TableMixin or GeoJsonMixin

[Nick Forbes-Smith]

@steve9164 to link old PR

[Stephen Davies]

See #3963

You're right about old. This PR is built on terriajs 7.