Adding free licence geolocation server OpenCage Geocoder to Maps

Current version of ILIAS (5.1) does support Google Maps and Open Layers Maps for displaying the maps and finding geolocation (e.g. find coordinates based on address). Unfortunately those two geocoding services do not use a free licence.

Google is only allowed for free accessible pages (but not within company or intranet).
See "Can I use the Google Maps API on a commercial website?"

OpenStreetMaps is also bounded by licence rules, as stated by this post in Mantis

OpenStreetMap is suggesting to use OpenCage Geocoder (among other services), which can be used in Free Trial after registration with very generouse conditions (less than 2.500 requests a day and 1 per sec).

Adding this geoservice to the list (map tiles could still be used from OpenStreetMap) would allow to use a service with appropriate licensing.

Additionally: a licence warnings and links to licence models in according sections  would be very helpfull for users, who are unaware of licences of Google Maps or Nominatim Server by OpenStreetMap.

Related FW-Pages:
Google Map Address Lookup
OpenLayers Maps
Set URLs for OSM-mirror and reverse geocoding server

1 Requirements

...

2 Additional Information

• Idea / concept: Wischniak, Stanislav [wischniak]
• Interest in funding: (please indicate if you are interested/able to fund this feature)
• Maintainer: (will be set by Jour Fixe / maintainer)
• Implementation of the feature is done by (will be set by Jour Fixe / maintainer)
• Testcases by: (please add your name if you want to create the testcases for this feature)

3 Discussion

4 Implementation

{please give a description of the final implementation and add screenshots if possible}

Test Cases

Test cases completed at {date} by {user}

• {Test case number linked to Testrail} : {test case title}

Approval

Approved at {date} by {user}.