MiniMapCamController.cs

using UnityEngine;

public class MiniMapCamController : MonoBehaviour
{
    [SerializeField]
    Camera m_cam;

    public void SetMapPosToThis(MeshFilter meshFilter)
    {
        SetMesh(meshFilter);
        // offset to the top of the mesh, with an extra up
        Vector3 center = meshFilter.transform.position + meshFilter.sharedMesh.bounds.center + Vector3.up;
        center.y += meshFilter.sharedMesh.bounds.extents.y;
        transform.position = center;
    }

    public void SetMesh(MeshFilter meshFilter)
    {
        // set ortho size to be the mesh size with a little buffer
        float size = meshFilter.sharedMesh.bounds.size.magnitude * 0.55f;
        m_cam.orthographicSize = size;
    }
}