Store and display feature collections

[simon-leech]

What?

• We need a way to easily call an API with request that will return multiple features. E.g. multiple drive times being returned.
• We need a way to then display all these features easily (using a type layer).
• We need a way to easily store these features to the database, where each feature will exist in a different column. This require some kind of object that has a key-value pair to distinguish what to store.
• Should the query that stores them be a stored query that runs just once? Or use the location_update query, but this might fire a lot of requests depending how many features are to be stored.
• We need to be able to check if the features are already populated and thus not run them again if so

[dbauszus-glx]

Geometry type entries are for displaying individual or multi geometries. Feature collections however need to be displayed as a vector layer.

An archipelago is a good example for a multi geometry.

A series of n drivetime catchments is not a multigeometry but a feature collection since each band is a feature with own properties.

Breaking a feature collection into features to be passed to a vector layer is not hard.

Difficulties arise when trying to store feature collections in a relational database. It is not feasible to create a table for each feature which has an associated feature collection. Neither is it recommended to create a table with n columns, with a column each representing a distinct feature geometry.

A geojson feature collection as a format for vector layers would solve the storage issue. A feature collection is a geojson standard. A feature collections can be read from a file. A feature collection can be stored in a JSON type PostGIS table field.