how to change esri mappoint to projectable data type
I need to capture the center point of the screen (which is in web mercator), reproject the point to degrees minutes and seconds. I have the center point of my screen as a esri map point, but I don't know how to change the type so the project function in the workflow will let me submit the point to a geometry service. Can someone help me on this.
J
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The Project Task activity has an input argument called "FeatureSet" that is of type IEnumerable<Graphic>. So you need to create one of those. The easiest way to do that is to wrap your MapPoint in a FeatureSet. A FeatureSet is an IEnumerable<Graphic> and you can create one from one or more geometries. For example: if you have a MapPoint in a variable called "point" you can create a FeatureSet with the VB expression:
New FeatureSet(point)
Also before using the Project Task activity (or any other Geometry Service operation) be sure to set the SpatialReference of your geometry.
Here is a sample workflow that demonstrates this: (https://support.geocortex.com/Data/Sites/1/userfiles/1725/projecttask.xaml) /Data/Sites/1/userfiles/1725/projecttask.xaml (save as).
--Ryan
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Thanks--
That works for me. Sometimes knowing how to do the smallest dumbest things can make the biggest difference.
J
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I see you "transfer to client" results(0).geometry. How do I convert that to a mappoint or get the x y and spatial reference for it? I have never use the transfer to client function.
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Hi Jeff,
I just used Transfer To Client so that you could "see" the output in the simulator. That activity can't really be used in a real workflow without some supporting custom code.
The easiest (laziest) way to get a MapPoint from a Geometry is to use the center of its extent:
results(0).Geometry.Extent.GetCenter()
To understand what is really going on... results(0).Geometry returns us an object of type Geometry. We know that this will in fact be a MapPoint (a particular type of Geometry), but the workflow framework doesn't know this. To be able to use it as a MapPoint we have to cast/convert it to the MapPoint type first. There are a couple ways to do this:
- In a VB expression you can perform a conversion: CType(results(0).Geometry, MapPoint)
- Use the Cast<T> activity and choose MapPoint when it prompts you for a type. This activity is kind of like the Assign activity, but it will also cast the object to the desired type.
--Ryan
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Excellent Answer! This was very helpful. Thanks greatly!
Sonia
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