Implement a terrain layer selector

[allyoucanmap]

Description

Now that we have a specific terrain layer we could introduce a selector to change the terrain provider of the cesium viewer then store the selected layer in the saved map. The behavior should be similar to the background selector but the UI should be improved for this purpose (see mockup).

Acceptance criteria

• [ ] The current background selector will be improved for managing also terrain layers for 3D config/activation from UI
• [ ] A terrain provider selector component will allow to change terrain provider in the 3D viewer

Other useful information

Mockup

• prototype branch

• Closed selector shows the selected background image. Size has been reduced compared to the previous selector

• Replaced the horizontal list with a compact vertical list, backgrounds and terrains will be listed in two separate groups. The Ellipsoid terrain will be always visible and cannot be edited or removed. The terrains list will be available when a user switch to 3D mode

• Clicking on the plus button of the Terrain section opens a dialog that allow to select different provider: Cesium, Cesium Ion, DDS/BIL WMS:

  • Cesium:

  • Cesium Ion:

  • DDS/BIL WMS:

• After a user create a terrain, the terrain will be visible on the list then a user can select it, remove it or edit it using a dialog similar to previous ones