Blazor Binding Shape Files with Geo-spatial Data

    The Ignite UI for Blazor map component, the IgbShapeDataSource class loads geo-spatial data (points/locations, polylines, polygons) from shape files and converts it to a collection of IgbShapefileRecord objects.

    Blazor Binding Shape Files with Geo-spatial Data Example

    The following table explains properties of the IgbShapeDataSource class for loading shape files.

    Property Type Description
    ShapefileSource string Specifies the Uri to a shape file (.shp) that contains geo-spatial data items.
    DatabaseSource string Specifies the Uri to a shape database file (.dbf) that contains a data table for geo-spatial data items.

    When both source properties are set to non-null values, then the IgbShapeDataSource object’s ImportAsync method is invoked which in return performs fetching and reading the shape files and finally doing the conversion. After this operation is complete, the IgbShapeDataSource is populated with IgbShapefileRecord objects and the ImportCompleted event is raised in order to notify about completed process of loading and converting geo-spatial data from shape files.

    Loading Shapefiles

    The following code creates an instance of the IgbShapeDataSource object for loading a shape file that contains locations of major cities in the world. It also demonstrates how to handle the ImportCompleted event as a prerequisite for binding data to the map component.

    Binding Shapefiles

    In the map component, Geographic Series are used for displaying geo-spatial data that is loaded from shape files. All types of Geographic Series have an DataSource property which can be bound to an array of objects. The IgbShapeDataSource is an example such array because it contains a list of IgbShapefileRecord objects.

    The IgbShapefileRecord class provides properties for storing geo-spatial data, listed in the following table.

    Property Description
    Points Contains all the points in one geo-spatial shape loaded from a shape file (.shp). For example, the country of Japan in shape file would be represented as a list of a list of points object, where:
    • The first list of points describes shape of Hokkaido island
    • The second list of points describes shape of Honshu island
    • The third list of points describes shape of Kyushu island
    • The fourth list of points describes shape of Shikoku island
    | | `Fields` |Contains a row of data from the shape database file (.dbf) keyed by a column name. For example, a data about county of Japan which includes population, area, name of a capital, etc.|

    This data structure is suitable for use in most Geographic Series as long as appropriate data columns are mapped to them.

    Code Snippet

    This code example assumes that shape files were loaded using the IgbShapeDataSource. The following code binds IgbGeographicPolylineSeries in the map component to the IgbShapeDataSource and maps the Points property of all IgbShapefileRecord objects.

    @using IgniteUI.Blazor.Controls


<IgbGeographicMap Height="100%" Width="100%" Zoomable="true">
    <IgbGeographicPolylineSeries ShapefileDataSource="@DataSource"
        ShapeFilterResolution="0.0"
        ShapeStrokeThickness="3"
        ShapeStroke="rgb(82, 82, 82, 0.4)"/>
</IgbGeographicMap>

@code {

    private ShapeDataSource DataSource;

    protected override void OnInitialized()
    {
        this.DataSource = new IgbShapeDataSource()
        {
            ShapefileSource = "https://static.infragistics.com/xplatform/shapes/WorldCableRoutes.shp",
            DatabaseSource = "https://static.infragistics.com/xplatform/shapes/WorldCableRoutes.dbf"
        };
    }
}

    API References