I have implemented a MiniMap based on textures or images, avoiding usage of the scene capture 2D, which however will be also available in future releases.
Here is my material which I use to present the map texture:
Map based on textures (Material)
In current version the widget supports only maps based on textures. The textures must be in a quadratic form and cover an quadratic area of the UE space which is centered around x=0 and y=0.
Customizable size and position
The Map widget can be set to any size as long as the width and height are same. The widget is placed on a canvas panel and can be docked anywhere in the viewport.
The map can be zoomed in and out. The zoom level can be adjusted from blueprint externally.
Dynamic POIs (Points of Interest)
The widget uses a collision sphere around the player character and detects bign and end overlap events. When such an event happens, the widget checks for specific tags under the actor and based on that adds POIs to the map and keeps track of them. When the actors leave the collision sphere, the POIs are removed.
Static POIs (Points of Interest)
Static POIs can be manually added and will be tracked always on the map even when out of range the POIs will be shown on the corner of the map and point in direction of that actor, which is useful for point to some game objectives or location further away.
Map to World translation
Clicking on the map will trigger an event dispatch which provides the map click location and the click location translated to world location.
The Sample Project on Github with tutorial on the wiki page: https://github.com/damirporobic/UE4_Minimap
Let me know if you would like to see some additional features.