ZoomPan

using System.Collections;
using System.Collections.Generic;

using UnityEngine;

public class ZoomPan : MonoBehaviour
{
    Vector3 touchStart;
    public float zoomOutMin = 1;
    public float zoomOutMax = 8;
    public Camera cameraMap;

    // Update is called once per frame
    void Update ()
    {
        if (Input.GetMouseButtonDown (0))
        {
            touchStart = cameraMap.ScreenToWorldPoint (Input.mousePosition);
        }
        if (Input.touchCount == 2)
        {
            Touch touchZero = Input.GetTouch (0);
            Touch touchOne = Input.GetTouch (1);

            Vector2 touchZeroPrevPos = touchZero.position - touchZero.deltaPosition;
            Vector2 touchOnePrevPos = touchOne.position - touchOne.deltaPosition;

            float prevMagnitude = (touchZeroPrevPos - touchOnePrevPos).magnitude;
            float currentMagnitude = (touchZero.position - touchOne.position).magnitude;

            float difference = currentMagnitude - prevMagnitude;

            zoom (difference * 0.01f);
        }
        else if (Input.GetMouseButton (0))
        {
            Vector3 direction = touchStart - cameraMap.ScreenToWorldPoint (Input.mousePosition);
            cameraMap.transform.position += direction;
        }
        zoom (Input.GetAxis ("Mouse ScrollWheel"));
    }

    public void zoom (float increment)
    {
        cameraMap.orthographicSize = Mathf.Clamp (cameraMap.orthographicSize - increment, zoomOutMin, zoomOutMax);
    }
}