Smooth touch for map

I have to make the 3Dmap motion somewhat free and smooth like we get in lerp. I donno how to apply in it, Please help me out...

i need free movement like hills of glory 3D game ..

using UnityEngine; using System.Collections;

public class PanCamera : MonoBehaviour {

 public float speed = 0.1f;
 public float MIN_X = 7f;
 public float MAX_X = 12f;
 public float MIN_Y = 8f;
 public float MAX_Y = 13f;
 public float MIN_Z = 10f;
 public float MAX_Z = 10f;
 public Vector3 nextPosition;
 public float moveSpeed;
 public int camAdjust = 10;

 // Use this for initialization
 void Start () {
 
 }
 
 // Update is called once per frame
 void Update () {
 
     if (Input.touchCount == 1 && Input.GetTouch (0).phase == TouchPhase.Moved) {
         Vector3 touchdeltaPosition = Input.GetTouch (0).deltaPosition;
         transform.Translate (-touchdeltaPosition.x * speed*Time.deltaTime, -touchdeltaPosition.y * speed*Time.deltaTime, 0);
         transform.position.y = Terrain.activeTerrain.SampleHeight(transform.position) + camAdjust;
         transform.position = new Vector3(
             Mathf.Clamp(transform.position.x, MIN_X, MAX_X),
             Mathf.Clamp(transform.position.y, MIN_Y, MAX_Y),
             Mathf.Clamp(transform.position.z, MIN_Z, MAX_Z));
     
     }
 }

}