Panning with SOAP controls

Another basic tool required by a GIS-based web application is the ability to move the map window over the SWD.

To allow panning in the four directions, add four buttons with these IDs:

  • panNorthButton
  • panEastButton
  • panWestButton and
  • panSouthButton.

TIP: Image Buttons will function in the same manner; this means you can use arrow icons instead of textual descriptions.

Double-click on each button in turn to create the event handler methods. Fill them in as below:

Copy 
Private Sub panNorthButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) 
Handles panNorthButton.Click
   Dim ex As SisExtent = oSis.SplitExtent(oSis.GetViewExtent())
   ' Pan by half the screen height
   Dim distance = (ex.max.y - ex.min.y) / 2
   oSis.SetViewExtent(ex.min.x, ex.min.y + distance, ex.min.z, ex.max.x, ex.max.y + distance, ex.max.z)
   RenderSis()
End Sub

 

Copy 
Private Sub panEastButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) 
Handles panEastButton.Click   
    Dim ex As SisExtent = oSis.SplitExtent(oSis.GetViewExtent())
   ' Pan by half the screen width
       Dim distance = (ex.max.x - ex.min.x) / 2
       oSis.SetViewExtent(ex.min.x + distance, ex.min.y, ex.min.z, ex.max.x + distance, ex.max.y, ex.max.z)
RenderSis()
End Sub
 
Copy 
Private Sub panEastButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
Handles panEastButton.Click
   Dim ex As SisExtent = oSis.SplitExtent(oSis.GetViewExtent())
   ' Pan by half the screen width
   Dim distance = (ex.max.x - ex.min.x) / 2
   oSis.SetViewExtent(ex.min.x + distance, ex.min.y, ex.min.z, ex.max.x + distance, ex.max.y, ex.max.z)
RenderSis()
End Sub