Map Download Feature for GeoNode v5

[ridoo]

This discussion thread intends to reduce noise on the issue about a map download feature request. To summarize the actual request:

GeoNode should allow an authorized user to download all data available from a map as zip file. The zip should include all visible datasets (allowed to be downloaded) in a plain data format (like shp or tiff) and (optionally) metadata and/or all linked resources as well.

Some old implementation fragments exist in GeoNode, but it is unclear at the moment if and how good those worked out (my latest test was not successful). For this reason (there may be others) these fragments are flagged to be removed in future GeoNode versions, i.e. upcoming v5. However, there is value for such a feature with regard to local reproducability in case where maps are offered as data products (data repository perspective).

Are you (GeoSolutions, who else?) interested in such an upstream feature, at all? Then we can discuss the pro/cons of a map download feature, what are the benefits and limitations, and what would be necessary for a slice-through which would leave out as much complexity as possible on a first approach.

We need to identify the components to be touched and try to keep communication flow simple. (Geo-)Server load is an aspect @giohappy raised as a valid concern, so what other non-functional requirements do we have to consider?

Pro

• single download of related data curated as map
• packaging results (curated as maps) .. maybe related: https://github.com/GeoNodeUserGroup-DE/GN-development/issues/7

Cons

• duplicate data, contrary to service principle
• possible high load and memory usage
• risk to trigger ETL expectations (formats, conversion, ..)

First Feature could include

• zip download
• vector as plain shp or geojson
• raster as tiff
• optional metadata
• optional linked documents

Limitations

• only one map-download in a queue (have to be async anyway)
• Configurable max size to limit resource exhaustion
• Just a button or simple modal window showing checkboxes for metadata and linked resources
• Exclude remote/harvested services (?)

Considerations:

• Locking map and datasets during download
• Asset handlers seem to be good candidate to use

Ideas

• Sending E-Mail when ready
• Sending Message when ready
• Have kind-of a status list
• Approving map downloads before download

Upstream Requirements

• What's necessary to make it an upstream feature?

Feel free to share your thoughts/doubts and extend these list with your ideas.

/cc @giohappy
/cc @mwallschlaeger
/cc @matthesrieke