ComponentOne Maps for ASP.NET Web Forms
Features / Vector Layer / Display shapes using GeoJson files
In This Topic
    Display shapes using GeoJson files
    In This Topic

    Besides vector objects, you can also add shapes on the maps using remote GeoJson files. This feature allows you to import data from a local file and load data from external domains.

    GeoJson features may include points enabling you to add addresses and locations, line-strings that can be used to represent streets and boundaries, polygons that let you mark political borders like countries and provinces, and multi-part collections of these types.

    The following topic demonstrates how to display shapes on the maps control, using a remote GeoJson file. Note that two .geo.json files have been added to the project, in the Resources folder.

     

    In order to download a .json file successfully, add the following markup between the <system.webServer> </system.webServer> tags, in the web.config file.

    <staticContent>
   <mimeMap fileExtension=".json" mimeType="application/json"/>
</staticContent>

    Add the following script between the <head></head> tags, to set the fill and opacity of the shapes that highlight cities from USA on the maps control.

    Script

    Source View
    Copy Code 
    <script type="text/javascript">
    function onUsShapeCreated(e, d) {
        d.shape.attr("fill", "#00F").attr("fill-opacity", 0.2);
    }
</script>

    Add the Maps control to the form and complete the following steps to use a GeoJson file to display shapes on the maps control.

    In Code

    1. Import the following assemblies:
      C#
      Copy Code 
      using C1.Web.Wijmo.Controls.C1Maps;
using C1.Web.Wijmo.Controls.C1Maps.GeoJson;
using GeoJsonFeature = C1.Web.Wijmo.Controls.C1Maps.GeoJson.Feature;
using System.Drawing;

      VB
      Copy Code 
      Imports C1.Web.Wijmo.Controls.C1Maps
Imports C1.Web.Wijmo.Controls.C1Maps.GeoJson
Imports GeoJsonFeature = C1.Web.Wijmo.Controls.C1Maps.GeoJson.Feature
Imports System.Drawing
    2. Add the following code to the Page_Load event to add two vector layers to display shapes on the maps control, using a GeoJson files:
      C#
      Copy Code 
      if (!IsPostBack)
{
    var uslayer = new C1VectorLayer();
    var countriesLayer = new C1VectorLayer();
    C1Maps1.Layers.Add(uslayer);
    C1Maps1.Layers.Add(countriesLayer);

    uslayer.OnClientShapeCreated = "onUsShapeCreated";
    uslayer.DataType = DataType.GeoJson;
    uslayer.DataUrl = "Resources/us.geo.json";

    countriesLayer.DataType = DataType.GeoJson;
    countriesLayer.DataUrl = "Resources/countries.geo.json";
}
      VB
      Copy Code 
      If Not IsPostBack Then
    Dim uslayer As New C1VectorLayer()
    Dim countriesLayer As New C1VectorLayer()
    C1Maps1.Layers.Add(uslayer)
    C1Maps1.Layers.Add(countriesLayer)

    uslayer.OnClientShapeCreated = "onUsShapeCreated"
    uslayer.DataType = DataType.GeoJson
    uslayer.DataUrl = "Resources/us.geo.json"

    countriesLayer.DataType = DataType.GeoJson
    countriesLayer.DataUrl = "Resources/countries.geo.json"
End If
    3. Run the project.

    What You've Accomplished

    The following image depicts a C1Maps control displaying all the countries of the world, in a black boundary and highlighting certain cities from USA in purple.