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Connect to WMS maps for web app

#1

Is it possible to connect to WMS compliant maps as part of using UI controls.
I would like to use UI controls and wms maps from different location e.g.
http://mapy.geoportal.gov.pl/wss/service/img/guest/ORTO/MapServer/WMSServer.

  1. Which solution from ThinkGeo is for this?
  2. Where can I configure it?

Thanks for answers

#2

Hi Poul,

it’s possible to access the provided WMS service with ThinkGeo Blazor UI control, with few changes of “Blazor Sample OGC Service Sample”. Here are the demo codes of MapView:

<MapView Id="map" @ref="map"
         Center="@(new PointShape(19.41710,51.57224))"
         Zoom="15"
         MapUnit="@ThinkGeo.Core.GeographyUnit.DecimalDegree"><OverlaysSetting>
        <WmsTileOverlay Id="WmsOverlay" Parameters="@parameters"
                        ServerUris="@serverUris"
                        TileHeight="512" TileWidth="512"></WmsTileOverlay>
    </OverlaysSetting>
    <MapToolsSetting>
        <MapTools>
            <ZoomBarMapTool />
        </MapTools>
    </MapToolsSetting>
</MapView>

@code {
    MapView map;
    Collection<Uri> serverUris = new Collection<Uri> { new Uri("http://mapy.geoportal.gov.pl/wss/service/img/guest/ORTO/MapServer/WMSServer") };
    Dictionary<string, string> parameters = new Dictionary<string, string>
{
        { "layers", "Raster"},
        { "STYLE", "default"},
        { "CRS","EPSG:4326"}
    };
}

Now it should work, but after the map is loaded, it shows the blank map with following error:

Access to image at 'http://mapy.geoportal.gov.pl/wss/service/img/guest/ORTO/MapServer/WMSServer?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&layers=Raster&STYLE=default&CRS=EPSG%3A4326&WIDTH=512&HEIGHT=512&STYLES=&BBOX=51.56982421875%2C19.40185546875%2C51.591796875%2C19.423828125' from origin 'http://localhost:64632' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Even enabled “crossOrigin:‘anonymous’” to allow “Crossing Domain Access”, still got the same error, could you please help check if the service supports “Access-Control-Allow-Origin”? If yes, we can check if any issues on my side. Sorry for the inconvenience.

If we paste the request URL of one tile, such as http://mapy.geoportal.gov.pl/wss/service/img/guest/ORTO/MapServer/WMSServer?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&layers=Raster&STYLE=default&CRS=EPSG%3A4326&WIDTH=512&HEIGHT=512&STYLES=&BBOX=51.56982421875%2C19.40185546875%2C51.591796875%2C19.423828125, a satellite image should show up in the browser, it’s proved the codes above is correct, the only problem is “Access-Control-Allow-Origin”. Here is the URL of this WMS service capabilities http://mapy.geoportal.gov.pl/wss/service/img/guest/ORTO/MapServer/WMSServer?request=GetCapabilities&version=1.3.0&SERVICE=WMS.

Thanks,
Johnny

#3

Thanks for the answer, I was looking for a solution all Saturday but it doesn’t work.

a) I have implemented CORS in ThinkGeo.UI.Blazor.HowDol but doesn’t work.

  1. Startup class
    readonly string MyAllowSpecificOrigins = “_myAllowSpecificOrigins”;
    public void ConfigureServices(IServiceCollection services)
    {
    services.AddCors(options =>
    {
    options.AddPolicy(MyAllowSpecificOrigins,
    builder =>
    {
    builder.AllowAnyOrigin()
    .SetIsOriginAllowed(isOriginAllowed: _ => true) or .AllowAnyOrigin()
    .AllowAnyMethod()
    .AllowAnyHeader();
    });
    });

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{

        app.UseCors(MyAllowSpecificOrigins);

b) maybe soluction is reverse proxy site?

Poul

#4

i found also discussion in this area on

#5

Hi Poul,

It looks your server is changing, I tried to view this link:
http://mapy.geoportal.gov.pl/wss/service/img/guest/ORTO/MapServer/WMSServer?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&layers=Raster&STYLE=default&CRS=EPSG%3A4326&WIDTH=512&HEIGHT=512&STYLES=&BBOX=51.56982421875%2C19.40185546875%2C51.591796875%2C19.423828125

It return a tile image, but when I try to visit it again after half an hour, it shows exception: Parameter ‘layers’ contains unacceptable layer names.

And I found the LAYERS=Raster is also not accepted by server but the layers=Raster works at the first, by default our parameter is used like LAYERS, could you please double check that?

I will do more test when the server is stable.

Regards,

Ethan