topic compare areas of Identify results in ArcGIS API for Silverlight Questions

compare areas of Identify results

DaveOrlando — Mon, 19 Dec 2011 18:24:53 GMT

Hello,

has anybody done something similar?...

I would like to compare the areas of the features returned from the 'identify' task before I add them to the list. I will create some code to sort the results in order of area, but the problem I have is that for display purposes I have hidded the 'area' field.

Is there a function out there that can do an area calculation based on the returned geometry (polygon)? using the rings maybe?.....

thanks,

Re: compare areas of Identify results

JenniferNery — Mon, 19 Dec 2011 19:37:32 GMT

If you are using API version 2.3 or 3.0 Beta 1, you can use this method: http://help.arcgis.com/en/webapi/silverlight/apiref/ESRI.ArcGIS.Client~ESRI.ArcGIS.Client.Geometry.Geodesic~Area.html.

Re: compare areas of Identify results

DaveOrlando — Mon, 19 Dec 2011 20:52:20 GMT

Unfortunately I am still in the dark ages of 2.2

I am taking my results from the Identify and feeding them into the GeometryService AreasAndLengths method, but I think I am about to abort for a few reasons.

1. the service takes too long to return and
2. I don't think I'll be able to reattach the areas to the proper polygon with certainty

have you seen a way to attach the results of the AreaAndLengths back onto the features (IList<Graphic>) being passed in? or add to an area property in the DataItem class show in the Identify example?

Re: compare areas of Identify results

JenniferNery — Sat, 11 Dec 2021 14:01:34 GMT

Yes, you can use 2nd parameter UserState, this can be any data type, which you can cast to the correct type in the completed event.

   geometryService.AreasAndLengthsCompleted += (s, e) =>
    {
     var originalGraphics = e.UserState as List<Graphic>;
     if (originalGraphics != null)
     {
     };
    };
   geometryService.AreasAndLengthsAsync(graphics, graphics);