Geospatial browsing visualisation

[mtiessen1175]

Display the positions of images/video frames (per volume) in one (or more) map(s). ToDo:

• [x] mechanism to load maps from web map service
  • which kind of service / maps shall be used?
• [x] update volume-settings-page to include selection of (several) maps per volume
• [x] mechanism to link / georeference images to corresponding map
  • read longitude/latidue coordinates from metadata / iFDO's
• [x] filtering mechanism (filter by):
  • geospatial attributes (e.g. area close to shoreline)
  • image attributes (e.g. particular species)

[mzur]

Here are my notes concerning this feature:

• Add a new filter option "filter by location" to the volume overview
• When the filter is selected, this opens a modal with the geo map (similar to the current map but without sidebar)
• The map shows image locations which can be selected with a drawn rectangle
• The map also shows all configured "browsing" layers (see #45)
• Additional layers can be added in the volume edit view
• An additional layer can be a georeferenced file or a link to a WMS source
• Layers can be ordered in the volume edit view

Lots of the removed geo overlay code can be reused here: https://github.com/biigle/geo/commit/055a6a72468bc7e53d74a80c442afa26cb16ea66