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Areas and Lengths Task

Andrew Flynn

What is the process to use a workflow to select polygons using a query and display their calculated area in an alert message?

 

I have set up the query task, but I am confused about the proper use of the Areas and Lengths task.  The help materials explain that this tool can be used to calculate the area of features selected in a query task, but there seems to be no input for a feature set, just a graphic. Also the results variable that is output is an "AreaAndLengths" type, which I'm not sure how to extract a string to display in an alert message. Any suggestions?

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  • Andrew Flynn

    I've been able to run the "Areas and Lengths" task in my workflow, however I do not know how to use the output to display that information in a message.

     

    I first extract geometry by using the "Get Geometries" task, which I then iterate through using a "For Each" command. After, I use the geometry to run the "Buffer" task, and generate a "Graphics" variable. That "Graphics variable is then used to run the "Areas and Lengths" task, but I am not sure how to use the output to display in a message. Any suggestions?
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  • Permanently deleted user
    Hi Andrew! You can use the output of the query task directly in the "Areas And Lenghts" activity. The "Feature Set" that is the output of the query task contains a property call "features" which a list of Graphics (which is what you need). So, in the graphics property of the "Areas And Lenghts" activity you can do MyFeatureSet1.features .   Regarding getting the values out of the returned variable, this vairable is of type "ESRI.ArcGIs.Client.Tasks.AreasAndLenghts". You can see the properties and methods of that on the ESRI API: http://help.arcgis.com/en/webapi/wpf/apiref/api_start.htm It basically has two properties: "Areas" and "Lengths". They are both a List of numbers:  MyALVariable.Areas  and  MyALVariable.Lengths   You can iterate through those using a for each and extract the values directly (it's a list of numbers). I would also recommend enabling "Intellisense" on the workflow designer (edit -> Enable Intellisense) this will help you a lot when trying to know the properties and methods available on a variable.   Hope it helps,   -Alejandro
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  • Andrew Flynn

    Thanks! Once I started looking at the properties of these variables everything quickly fell into place. I appreciate the response.

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