WKT Geometry

TatukGIS Internet Server Samples

Use list to change WKT type:     

Edit WKT string :

Source code

This sample, created using the TatukGIS Internet Server, demonstrates how to do the following:

  • build geometry from WKT
  • use GisCreateShapeFromWKT method
  • use POINT(), MULTIPOINT(), LINESTRING(), MULTILINESTRING(), and POLYGON()

Try editing the shape geometry by changing the information in the "Editor WKT String" field and then clicking on the "Change" button.

wkt.aspx    Top 

                            
                            
<%@ Page Language="VB" Debug="True" %>
<%@ Register TagPrefix="ttkGIS" Namespace="TatukGIS.IS" Assembly="TatukGIS.IS" %>
<script runat="server">

    Dim GisUtils As API.XGIS_Utils
    Dim layerObj As API.XGIS_LayerVector    
    
    dim type1 as string = "POINT (30 30)"
    dim type2 as string = "MULTIPOINT (4 4, 5 5, 6 6 ,7 7)"
    dim type3 as string = "LINESTRING (3 3, 10 10)"
    dim type4 as string = "MULTILINESTRING ((1 1, 3 3, 4 4, 6 6),(2 4, 5 7, 8 10, 11 13))"
    dim type5 as string = "POLYGON( ( 5 5, 25 5, 25 25, 5 25, 5 5), ( 10 10, 10 20, 20 20, 20 10, 10 10))"
   
    Sub GIS_SetMaxExtent()
        dim ex as New API.XGIS_Extent
       'set max extent; GIS.API.RestrictedDrag has to be set on False
        ex.XMin = -6
        ex.YMin = -1
        ex.XMax = 36
        ex.YMax = 31
        GIS.API.VisibleExtent = ex
    End Sub
    
    Sub GIS_FullExtent_Click(sender As Object, e As ImageClickEventArgs)
        GIS_SetMaxExtent()
    End Sub
    
    Sub GIS_ZoomIn_Click(sender As Object, e As ImageClickEventArgs)
        GIS.ZoomIn()
    End Sub
    
    Sub GIS_ZoomOut_Click(sender As Object, e As ImageClickEventArgs)
        GIS.ZoomOut()
    End Sub
    
    Sub GIS_Smaller_Click(sender As Object, e As ImageClickEventArgs)
        GIS.Width  = Unit.Pixel( GIS.Width.Value  - 54 )
        GIS.Height = Unit.Pixel( GIS.Height.Value - 40 )
    End Sub
    
    Sub GIS_Larger_Click(sender As Object, e As ImageClickEventArgs)
        GIS.Width  = Unit.Pixel( GIS.Width.Value  + 54 )
        GIS.Height = Unit.Pixel( GIS.Height.Value + 40 )
    End Sub
    
    Sub GIS_Load(sender As Object, e As EventArgs)
        GisUtils = New API.XGIS_Utils

        layerObj = New API.XGIS_LayerVector
        layerObj.Name = "output"
        layerObj.Params.Area.Color = RGB(255, 0, 0)
        GIS.API.Add(layerObj)
        
        if not Page.IsPostBack then
            lbl_Info.Text = type5
            session("listType") = 5
        end if
        GIS.API.RestrictedDrag = False
    End Sub
    
    Sub GIS_BeforePaint(sender As Object, e As PaintEventArgs)
        Dim shp As API.XGIS_Shape
    
        If layerObj Is Nothing Then Exit Sub
    
       'change text with WKT string if new object type is set
        if session("listType") <> list_ShapeType.SelectedItem.Value then
            Select Case list_ShapeType.SelectedItem.Value
                Case 1
                    lbl_Info.Text = type1
                Case 2
                    lbl_Info.Text = type2
                Case 3
                    lbl_Info.Text = type3
                Case 4
                    lbl_Info.Text = type4
                Case 5
                    lbl_Info.Text = type5
            End Select
            session("listType") = list_ShapeType.SelectedItem.Value
        end if
    
       'try to build shape from string written in lbl_Info.Text
        try
            shp = GisUtils.GisCreateShapeFromWKT(lbl_Info.Text)
        catch
            shp = Nothing
        end try
    
        If Not shp Is Nothing Then
            layerObj.AddShape(shp)
            shp = Nothing
            lbl_Info.BackColor = System.Drawing.Color.White
            session("error") = False
        Else
            lbl_Info.BackColor = System.Drawing.Color.Red
            session("error") = True
        End If
    
       'set proper extent
        If not Page.IsPostBack then
            GIS_SetMaxExtent()
        Else
            GIS.API.VisibleExtent = session("ex")
        End If
    End Sub
    
    Sub GIS_Paint(sender As Object, e As PaintEventArgs)
        GIS.Draw()
    
       'remember extention if new shape was correct
        if session("error") = False then
            session("ex") = GIS.API.VisibleExtent
        end if
    End Sub


</script>
<html>
<head>
    <title>TatukGIS IS Sample - WKT</title>
    <link href="style.css" type="text/css" rel="stylesheet" />
</head>
<body>
    <a name="top">
    <h1>WKT
    </h1>
    <h2 class="comment"><a href="../../samplesAPI.htm">TatukGIS Internet Server Samples</a>
    </h2>
    <form runat="server">
        <table cellspacing="0" cellpadding="0" border="0">
            <tbody>
                <tr>
                    <td>
                        <asp:ImageButton id="GIS_FullExtent" onclick="GIS_FullExtent_Click" runat="server" ImageUrl="/TatukGIS_IS8/img/fullextent.gif"></asp:ImageButton>
                        <asp:ImageButton id="GIS_ZoomIn" onclick="GIS_ZoomIn_Click" runat="server" ImageUrl="/TatukGIS_IS8/img/zoomin.gif"></asp:ImageButton>
                        <asp:ImageButton id="GIS_ZoomOut" onclick="GIS_ZoomOut_Click" runat="server" ImageUrl="/TatukGIS_IS8/img/zoomout.gif"></asp:ImageButton>
                    </td>
                    <td align="right">
                        <asp:ImageButton id="GIS_Smaller" onclick="GIS_Smaller_Click" runat="server" ImageUrl="/TatukGIS_IS8/img/smaller.gif"></asp:ImageButton>
                        <asp:ImageButton id="GIS_Larger" onclick="GIS_Larger_Click" runat="server" ImageUrl="/TatukGIS_IS8/img/larger.gif"></asp:ImageButton>
                    </td>
                </tr>
                <tr>
                    <td colspan="2">
                        <p>
                            <ttkGIS:XGIS_VIEWERIS id="GIS" runat="server" Height="280px" Width="360px" OnLoad="GIS_Load" BorderColor="CornflowerBlue" BorderWidth="1px" OnPaint="GIS_Paint" OnBeforePaint="GIS_BeforePaint"></ttkGIS:XGIS_VIEWERIS>
                        </p>
                    </td>
                </tr>
                <tr>
                    <td colspan="2">
                        <p>
                        </p>
                    </td>
                </tr>
            </tbody>
        </table>
        <p>
            <asp:Label id="Label1" runat="server" cssclass="bold" forecolor="Gray">Use list to
            change WKT type: </asp:Label>    <asp:DropDownList id="list_ShapeType" runat="server" AutoPostBack="True">
                <asp:ListItem Value="1">POINT</asp:ListItem>
                <asp:ListItem Value="2">MULTIPOINT</asp:ListItem>
                <asp:ListItem Value="3">LINESTRING</asp:ListItem>
                <asp:ListItem Value="4">MULTILINESTRING</asp:ListItem>
                <asp:ListItem Value="5" Selected="True">POLYGON</asp:ListItem>
            </asp:DropDownList>
        </p>
        <p>
            <asp:Label id="Label2" runat="server" cssclass="bold" forecolor="Gray">Edit WKT string</asp:Label>:
            <br />
            <asp:TextBox id="lbl_Info" runat="server" Width="476px"></asp:TextBox>
            <asp:Button id="Btn_Change" runat="server" Text="Change"></asp:Button>
        </p>
    </form>
    </a>
</body>
</html>