silverlight image service display errors

RyanKoehnen

I have a couple of issues that I can't figure out when trying to control how and image service is displayed.

The first being, setting ArcGISImageServiceLayer.ImageFormat to anything but JPGPNG does not seem to have any effect. I know this because I have an image/raster with nodata values. JPG doesn't support transparency, and the silverlight app will not display nodata as transparent when using PNG8 or PNG24.

The second issue I'm having is with setting a colormap on a ArcGISImageServiceLayer that has negative values in the raster. Even though I am populating the colormap array with the proper values, all but the negative values are being displayed correctly. The negative values are being display as random colors or black. The negative values in this example are from -808 to 0. The image being served is an integer raster.

Anybody have a clue? Am I doing something incorrectly?

Sample code below and image attached-

    public class DisplayRaster : ICommand
    {

        #region ICommand members
        public void Execute(object parameter)
        {
            ArcGISImageServiceLayer aglLayer = new ArcGISImageServiceLayer()
            {
                Url = "https://gis.projectportal.net/ArcGIS/rest/services/2028-0001/CAG_Surface_Height_AGL/ImageServer",
                ProxyURL = "http://gis.projectportal.net/apps/cag_demo/proxy.ashx",
                ID = "HeightAGLLayer",
                ImageFormat = ArcGISImageServiceLayer.ImageServiceImageFormat.JPGPNG,
                NoData = 32767,
                Interpolation = ArcGISImageServiceLayer.ImageServiceInterpolation.NearestNeighbor,
                Visible = true
            };

            aglLayer.SetValue(MapApplication.LayerNameProperty, "Height AGL");

            aglLayer.Initialized += new EventHandler<EventArgs>(aglLayer_Initialized);

            MapApplication.Current.Map.Layers.Add(aglLayer);
        }

        void aglLayer_Initialized(object sender, EventArgs e)
        {
            ArcGISImageServiceLayer aglLayer = (ArcGISImageServiceLayer) MapApplication.Current.Map.Layers["HeightAGLLayer"];

            int[][] colormap = CreateColorMap(aglLayer);

            Dictionary<string, object> rasterParams = new Dictionary<string, object>();
            rasterParams.Add("Colormap", colormap);

            RenderingRule rr = new RenderingRule()
            {
                RasterFunctionName = "Colormap",
                VariableName = "Raster",
                RasterFunctionArguments = rasterParams
            };

            aglLayer.RenderingRule = rr;
            aglLayer.Refresh();
        }

        public bool CanExecute(object parameter)
        {
            // Return true so that the command can always be executed
            return true;
        }

        public event EventHandler CanExecuteChanged;

        #endregion

        private int[][] CreateColorMap(ArcGISImageServiceLayer aglLayer)
        {
            int maxValue = System.Convert.ToInt32(aglLayer.MaxValues[0]);
            //minValue in this example ends up being -808
            int minValue = System.Convert.ToInt32(aglLayer.MinValues[0]);
            int span = maxValue - minValue;

            int[][] colorMap = new int[span][];

            //set everything below 1000 to red, above 1000 to green
            for (int i = 0; i < span; i++)
            {
                if (minValue + i < 1000)
                    colorMap = new int[] { minValue + i, 255, 0, 0 };
                else
                    colorMap = new int[] { minValue + i, 0, 255, 0 };
            }

            return colorMap;
        }
    }

sampleimageservice.jpg

WenxueJu

Ryan,

Thanks for providing more details, I posted some workarounds on REST API forum: http://forums.arcgis.com/threads/48593-Image-service-display-errors, could you check that out?

Wenxue